1#define MINIMAL_STDERR_OUTPUT
2
3#include "llvm/Analysis/Passes.h"
4#include "llvm/Analysis/Verifier.h"
5#include "llvm/ExecutionEngine/ExecutionEngine.h"
6#include "llvm/ExecutionEngine/MCJIT.h"
7#include "llvm/ExecutionEngine/ObjectCache.h"
8#include "llvm/ExecutionEngine/SectionMemoryManager.h"
9#include "llvm/IR/DataLayout.h"
10#include "llvm/IR/DerivedTypes.h"
11#include "llvm/IR/IRBuilder.h"
12#include "llvm/IR/LLVMContext.h"
13#include "llvm/IR/Module.h"
14#include "llvm/IRReader/IRReader.h"
15#include "llvm/PassManager.h"
16#include "llvm/Support/CommandLine.h"
17#include "llvm/Support/FileSystem.h"
18#include "llvm/Support/Path.h"
19#include "llvm/Support/raw_ostream.h"
20#include "llvm/Support/SourceMgr.h"
21#include "llvm/Support/TargetSelect.h"
22#include "llvm/Transforms/Scalar.h"
23#include <cstdio>
24#include <map>
25#include <string>
26#include <vector>
27using namespace llvm;
28
29//===----------------------------------------------------------------------===//
30// Command-line options
31//===----------------------------------------------------------------------===//
32
33cl::opt<std::string>
34InputIR("input-IR",
35        cl::desc("Specify the name of an IR file to load for function definitions"),
36        cl::value_desc("input IR file name"));
37
38cl::opt<bool>
39UseObjectCache("use-object-cache",
40               cl::desc("Enable use of the MCJIT object caching"),
41               cl::init(false));
42
43//===----------------------------------------------------------------------===//
44// Lexer
45//===----------------------------------------------------------------------===//
46
47// The lexer returns tokens [0-255] if it is an unknown character, otherwise one
48// of these for known things.
49enum Token {
50  tok_eof = -1,
51
52  // commands
53  tok_def = -2, tok_extern = -3,
54
55  // primary
56  tok_identifier = -4, tok_number = -5,
57
58  // control
59  tok_if = -6, tok_then = -7, tok_else = -8,
60  tok_for = -9, tok_in = -10,
61
62  // operators
63  tok_binary = -11, tok_unary = -12,
64
65  // var definition
66  tok_var = -13
67};
68
69static std::string IdentifierStr;  // Filled in if tok_identifier
70static double NumVal;              // Filled in if tok_number
71
72/// gettok - Return the next token from standard input.
73static int gettok() {
74  static int LastChar = ' ';
75
76  // Skip any whitespace.
77  while (isspace(LastChar))
78    LastChar = getchar();
79
80  if (isalpha(LastChar)) { // identifier: [a-zA-Z][a-zA-Z0-9]*
81    IdentifierStr = LastChar;
82    while (isalnum((LastChar = getchar())))
83      IdentifierStr += LastChar;
84
85    if (IdentifierStr == "def") return tok_def;
86    if (IdentifierStr == "extern") return tok_extern;
87    if (IdentifierStr == "if") return tok_if;
88    if (IdentifierStr == "then") return tok_then;
89    if (IdentifierStr == "else") return tok_else;
90    if (IdentifierStr == "for") return tok_for;
91    if (IdentifierStr == "in") return tok_in;
92    if (IdentifierStr == "binary") return tok_binary;
93    if (IdentifierStr == "unary") return tok_unary;
94    if (IdentifierStr == "var") return tok_var;
95    return tok_identifier;
96  }
97
98  if (isdigit(LastChar) || LastChar == '.') {   // Number: [0-9.]+
99    std::string NumStr;
100    do {
101      NumStr += LastChar;
102      LastChar = getchar();
103    } while (isdigit(LastChar) || LastChar == '.');
104
105    NumVal = strtod(NumStr.c_str(), 0);
106    return tok_number;
107  }
108
109  if (LastChar == '#') {
110    // Comment until end of line.
111    do LastChar = getchar();
112    while (LastChar != EOF && LastChar != '\n' && LastChar != '\r');
113
114    if (LastChar != EOF)
115      return gettok();
116  }
117
118  // Check for end of file.  Don't eat the EOF.
119  if (LastChar == EOF)
120    return tok_eof;
121
122  // Otherwise, just return the character as its ascii value.
123  int ThisChar = LastChar;
124  LastChar = getchar();
125  return ThisChar;
126}
127
128//===----------------------------------------------------------------------===//
129// Abstract Syntax Tree (aka Parse Tree)
130//===----------------------------------------------------------------------===//
131
132/// ExprAST - Base class for all expression nodes.
133class ExprAST {
134public:
135  virtual ~ExprAST() {}
136  virtual Value *Codegen() = 0;
137};
138
139/// NumberExprAST - Expression class for numeric literals like "1.0".
140class NumberExprAST : public ExprAST {
141  double Val;
142public:
143  NumberExprAST(double val) : Val(val) {}
144  virtual Value *Codegen();
145};
146
147/// VariableExprAST - Expression class for referencing a variable, like "a".
148class VariableExprAST : public ExprAST {
149  std::string Name;
150public:
151  VariableExprAST(const std::string &name) : Name(name) {}
152  const std::string &getName() const { return Name; }
153  virtual Value *Codegen();
154};
155
156/// UnaryExprAST - Expression class for a unary operator.
157class UnaryExprAST : public ExprAST {
158  char Opcode;
159  ExprAST *Operand;
160public:
161  UnaryExprAST(char opcode, ExprAST *operand)
162    : Opcode(opcode), Operand(operand) {}
163  virtual Value *Codegen();
164};
165
166/// BinaryExprAST - Expression class for a binary operator.
167class BinaryExprAST : public ExprAST {
168  char Op;
169  ExprAST *LHS, *RHS;
170public:
171  BinaryExprAST(char op, ExprAST *lhs, ExprAST *rhs)
172    : Op(op), LHS(lhs), RHS(rhs) {}
173  virtual Value *Codegen();
174};
175
176/// CallExprAST - Expression class for function calls.
177class CallExprAST : public ExprAST {
178  std::string Callee;
179  std::vector<ExprAST*> Args;
180public:
181  CallExprAST(const std::string &callee, std::vector<ExprAST*> &args)
182    : Callee(callee), Args(args) {}
183  virtual Value *Codegen();
184};
185
186/// IfExprAST - Expression class for if/then/else.
187class IfExprAST : public ExprAST {
188  ExprAST *Cond, *Then, *Else;
189public:
190  IfExprAST(ExprAST *cond, ExprAST *then, ExprAST *_else)
191  : Cond(cond), Then(then), Else(_else) {}
192  virtual Value *Codegen();
193};
194
195/// ForExprAST - Expression class for for/in.
196class ForExprAST : public ExprAST {
197  std::string VarName;
198  ExprAST *Start, *End, *Step, *Body;
199public:
200  ForExprAST(const std::string &varname, ExprAST *start, ExprAST *end,
201             ExprAST *step, ExprAST *body)
202    : VarName(varname), Start(start), End(end), Step(step), Body(body) {}
203  virtual Value *Codegen();
204};
205
206/// VarExprAST - Expression class for var/in
207class VarExprAST : public ExprAST {
208  std::vector<std::pair<std::string, ExprAST*> > VarNames;
209  ExprAST *Body;
210public:
211  VarExprAST(const std::vector<std::pair<std::string, ExprAST*> > &varnames,
212             ExprAST *body)
213  : VarNames(varnames), Body(body) {}
214
215  virtual Value *Codegen();
216};
217
218/// PrototypeAST - This class represents the "prototype" for a function,
219/// which captures its argument names as well as if it is an operator.
220class PrototypeAST {
221  std::string Name;
222  std::vector<std::string> Args;
223  bool isOperator;
224  unsigned Precedence;  // Precedence if a binary op.
225public:
226  PrototypeAST(const std::string &name, const std::vector<std::string> &args,
227               bool isoperator = false, unsigned prec = 0)
228  : Name(name), Args(args), isOperator(isoperator), Precedence(prec) {}
229
230  bool isUnaryOp() const { return isOperator && Args.size() == 1; }
231  bool isBinaryOp() const { return isOperator && Args.size() == 2; }
232
233  char getOperatorName() const {
234    assert(isUnaryOp() || isBinaryOp());
235    return Name[Name.size()-1];
236  }
237
238  unsigned getBinaryPrecedence() const { return Precedence; }
239
240  Function *Codegen();
241
242  void CreateArgumentAllocas(Function *F);
243};
244
245/// FunctionAST - This class represents a function definition itself.
246class FunctionAST {
247  PrototypeAST *Proto;
248  ExprAST *Body;
249public:
250  FunctionAST(PrototypeAST *proto, ExprAST *body)
251    : Proto(proto), Body(body) {}
252
253  Function *Codegen();
254};
255
256//===----------------------------------------------------------------------===//
257// Parser
258//===----------------------------------------------------------------------===//
259
260/// CurTok/getNextToken - Provide a simple token buffer.  CurTok is the current
261/// token the parser is looking at.  getNextToken reads another token from the
262/// lexer and updates CurTok with its results.
263static int CurTok;
264static int getNextToken() {
265  return CurTok = gettok();
266}
267
268/// BinopPrecedence - This holds the precedence for each binary operator that is
269/// defined.
270static std::map<char, int> BinopPrecedence;
271
272/// GetTokPrecedence - Get the precedence of the pending binary operator token.
273static int GetTokPrecedence() {
274  if (!isascii(CurTok))
275    return -1;
276
277  // Make sure it's a declared binop.
278  int TokPrec = BinopPrecedence[CurTok];
279  if (TokPrec <= 0) return -1;
280  return TokPrec;
281}
282
283/// Error* - These are little helper functions for error handling.
284ExprAST *Error(const char *Str) { fprintf(stderr, "Error: %s\n", Str);return 0;}
285PrototypeAST *ErrorP(const char *Str) { Error(Str); return 0; }
286FunctionAST *ErrorF(const char *Str) { Error(Str); return 0; }
287
288static ExprAST *ParseExpression();
289
290/// identifierexpr
291///   ::= identifier
292///   ::= identifier '(' expression* ')'
293static ExprAST *ParseIdentifierExpr() {
294  std::string IdName = IdentifierStr;
295
296  getNextToken();  // eat identifier.
297
298  if (CurTok != '(') // Simple variable ref.
299    return new VariableExprAST(IdName);
300
301  // Call.
302  getNextToken();  // eat (
303  std::vector<ExprAST*> Args;
304  if (CurTok != ')') {
305    while (1) {
306      ExprAST *Arg = ParseExpression();
307      if (!Arg) return 0;
308      Args.push_back(Arg);
309
310      if (CurTok == ')') break;
311
312      if (CurTok != ',')
313        return Error("Expected ')' or ',' in argument list");
314      getNextToken();
315    }
316  }
317
318  // Eat the ')'.
319  getNextToken();
320
321  return new CallExprAST(IdName, Args);
322}
323
324/// numberexpr ::= number
325static ExprAST *ParseNumberExpr() {
326  ExprAST *Result = new NumberExprAST(NumVal);
327  getNextToken(); // consume the number
328  return Result;
329}
330
331/// parenexpr ::= '(' expression ')'
332static ExprAST *ParseParenExpr() {
333  getNextToken();  // eat (.
334  ExprAST *V = ParseExpression();
335  if (!V) return 0;
336
337  if (CurTok != ')')
338    return Error("expected ')'");
339  getNextToken();  // eat ).
340  return V;
341}
342
343/// ifexpr ::= 'if' expression 'then' expression 'else' expression
344static ExprAST *ParseIfExpr() {
345  getNextToken();  // eat the if.
346
347  // condition.
348  ExprAST *Cond = ParseExpression();
349  if (!Cond) return 0;
350
351  if (CurTok != tok_then)
352    return Error("expected then");
353  getNextToken();  // eat the then
354
355  ExprAST *Then = ParseExpression();
356  if (Then == 0) return 0;
357
358  if (CurTok != tok_else)
359    return Error("expected else");
360
361  getNextToken();
362
363  ExprAST *Else = ParseExpression();
364  if (!Else) return 0;
365
366  return new IfExprAST(Cond, Then, Else);
367}
368
369/// forexpr ::= 'for' identifier '=' expr ',' expr (',' expr)? 'in' expression
370static ExprAST *ParseForExpr() {
371  getNextToken();  // eat the for.
372
373  if (CurTok != tok_identifier)
374    return Error("expected identifier after for");
375
376  std::string IdName = IdentifierStr;
377  getNextToken();  // eat identifier.
378
379  if (CurTok != '=')
380    return Error("expected '=' after for");
381  getNextToken();  // eat '='.
382
383
384  ExprAST *Start = ParseExpression();
385  if (Start == 0) return 0;
386  if (CurTok != ',')
387    return Error("expected ',' after for start value");
388  getNextToken();
389
390  ExprAST *End = ParseExpression();
391  if (End == 0) return 0;
392
393  // The step value is optional.
394  ExprAST *Step = 0;
395  if (CurTok == ',') {
396    getNextToken();
397    Step = ParseExpression();
398    if (Step == 0) return 0;
399  }
400
401  if (CurTok != tok_in)
402    return Error("expected 'in' after for");
403  getNextToken();  // eat 'in'.
404
405  ExprAST *Body = ParseExpression();
406  if (Body == 0) return 0;
407
408  return new ForExprAST(IdName, Start, End, Step, Body);
409}
410
411/// varexpr ::= 'var' identifier ('=' expression)?
412//                    (',' identifier ('=' expression)?)* 'in' expression
413static ExprAST *ParseVarExpr() {
414  getNextToken();  // eat the var.
415
416  std::vector<std::pair<std::string, ExprAST*> > VarNames;
417
418  // At least one variable name is required.
419  if (CurTok != tok_identifier)
420    return Error("expected identifier after var");
421
422  while (1) {
423    std::string Name = IdentifierStr;
424    getNextToken();  // eat identifier.
425
426    // Read the optional initializer.
427    ExprAST *Init = 0;
428    if (CurTok == '=') {
429      getNextToken(); // eat the '='.
430
431      Init = ParseExpression();
432      if (Init == 0) return 0;
433    }
434
435    VarNames.push_back(std::make_pair(Name, Init));
436
437    // End of var list, exit loop.
438    if (CurTok != ',') break;
439    getNextToken(); // eat the ','.
440
441    if (CurTok != tok_identifier)
442      return Error("expected identifier list after var");
443  }
444
445  // At this point, we have to have 'in'.
446  if (CurTok != tok_in)
447    return Error("expected 'in' keyword after 'var'");
448  getNextToken();  // eat 'in'.
449
450  ExprAST *Body = ParseExpression();
451  if (Body == 0) return 0;
452
453  return new VarExprAST(VarNames, Body);
454}
455
456/// primary
457///   ::= identifierexpr
458///   ::= numberexpr
459///   ::= parenexpr
460///   ::= ifexpr
461///   ::= forexpr
462///   ::= varexpr
463static ExprAST *ParsePrimary() {
464  switch (CurTok) {
465  default: return Error("unknown token when expecting an expression");
466  case tok_identifier: return ParseIdentifierExpr();
467  case tok_number:     return ParseNumberExpr();
468  case '(':            return ParseParenExpr();
469  case tok_if:         return ParseIfExpr();
470  case tok_for:        return ParseForExpr();
471  case tok_var:        return ParseVarExpr();
472  }
473}
474
475/// unary
476///   ::= primary
477///   ::= '!' unary
478static ExprAST *ParseUnary() {
479  // If the current token is not an operator, it must be a primary expr.
480  if (!isascii(CurTok) || CurTok == '(' || CurTok == ',')
481    return ParsePrimary();
482
483  // If this is a unary operator, read it.
484  int Opc = CurTok;
485  getNextToken();
486  if (ExprAST *Operand = ParseUnary())
487    return new UnaryExprAST(Opc, Operand);
488  return 0;
489}
490
491/// binoprhs
492///   ::= ('+' unary)*
493static ExprAST *ParseBinOpRHS(int ExprPrec, ExprAST *LHS) {
494  // If this is a binop, find its precedence.
495  while (1) {
496    int TokPrec = GetTokPrecedence();
497
498    // If this is a binop that binds at least as tightly as the current binop,
499    // consume it, otherwise we are done.
500    if (TokPrec < ExprPrec)
501      return LHS;
502
503    // Okay, we know this is a binop.
504    int BinOp = CurTok;
505    getNextToken();  // eat binop
506
507    // Parse the unary expression after the binary operator.
508    ExprAST *RHS = ParseUnary();
509    if (!RHS) return 0;
510
511    // If BinOp binds less tightly with RHS than the operator after RHS, let
512    // the pending operator take RHS as its LHS.
513    int NextPrec = GetTokPrecedence();
514    if (TokPrec < NextPrec) {
515      RHS = ParseBinOpRHS(TokPrec+1, RHS);
516      if (RHS == 0) return 0;
517    }
518
519    // Merge LHS/RHS.
520    LHS = new BinaryExprAST(BinOp, LHS, RHS);
521  }
522}
523
524/// expression
525///   ::= unary binoprhs
526///
527static ExprAST *ParseExpression() {
528  ExprAST *LHS = ParseUnary();
529  if (!LHS) return 0;
530
531  return ParseBinOpRHS(0, LHS);
532}
533
534/// prototype
535///   ::= id '(' id* ')'
536///   ::= binary LETTER number? (id, id)
537///   ::= unary LETTER (id)
538static PrototypeAST *ParsePrototype() {
539  std::string FnName;
540
541  unsigned Kind = 0; // 0 = identifier, 1 = unary, 2 = binary.
542  unsigned BinaryPrecedence = 30;
543
544  switch (CurTok) {
545  default:
546    return ErrorP("Expected function name in prototype");
547  case tok_identifier:
548    FnName = IdentifierStr;
549    Kind = 0;
550    getNextToken();
551    break;
552  case tok_unary:
553    getNextToken();
554    if (!isascii(CurTok))
555      return ErrorP("Expected unary operator");
556    FnName = "unary";
557    FnName += (char)CurTok;
558    Kind = 1;
559    getNextToken();
560    break;
561  case tok_binary:
562    getNextToken();
563    if (!isascii(CurTok))
564      return ErrorP("Expected binary operator");
565    FnName = "binary";
566    FnName += (char)CurTok;
567    Kind = 2;
568    getNextToken();
569
570    // Read the precedence if present.
571    if (CurTok == tok_number) {
572      if (NumVal < 1 || NumVal > 100)
573        return ErrorP("Invalid precedecnce: must be 1..100");
574      BinaryPrecedence = (unsigned)NumVal;
575      getNextToken();
576    }
577    break;
578  }
579
580  if (CurTok != '(')
581    return ErrorP("Expected '(' in prototype");
582
583  std::vector<std::string> ArgNames;
584  while (getNextToken() == tok_identifier)
585    ArgNames.push_back(IdentifierStr);
586  if (CurTok != ')')
587    return ErrorP("Expected ')' in prototype");
588
589  // success.
590  getNextToken();  // eat ')'.
591
592  // Verify right number of names for operator.
593  if (Kind && ArgNames.size() != Kind)
594    return ErrorP("Invalid number of operands for operator");
595
596  return new PrototypeAST(FnName, ArgNames, Kind != 0, BinaryPrecedence);
597}
598
599/// definition ::= 'def' prototype expression
600static FunctionAST *ParseDefinition() {
601  getNextToken();  // eat def.
602  PrototypeAST *Proto = ParsePrototype();
603  if (Proto == 0) return 0;
604
605  if (ExprAST *E = ParseExpression())
606    return new FunctionAST(Proto, E);
607  return 0;
608}
609
610/// toplevelexpr ::= expression
611static FunctionAST *ParseTopLevelExpr() {
612  if (ExprAST *E = ParseExpression()) {
613    // Make an anonymous proto.
614    PrototypeAST *Proto = new PrototypeAST("", std::vector<std::string>());
615    return new FunctionAST(Proto, E);
616  }
617  return 0;
618}
619
620/// external ::= 'extern' prototype
621static PrototypeAST *ParseExtern() {
622  getNextToken();  // eat extern.
623  return ParsePrototype();
624}
625
626//===----------------------------------------------------------------------===//
627// Quick and dirty hack
628//===----------------------------------------------------------------------===//
629
630// FIXME: Obviously we can do better than this
631std::string GenerateUniqueName(const char *root)
632{
633  static int i = 0;
634  char s[16];
635  sprintf(s, "%s%d", root, i++);
636  std::string S = s;
637  return S;
638}
639
640std::string MakeLegalFunctionName(std::string Name)
641{
642  std::string NewName;
643  if (!Name.length())
644      return GenerateUniqueName("anon_func_");
645
646  // Start with what we have
647  NewName = Name;
648
649  // Look for a numberic first character
650  if (NewName.find_first_of("0123456789") == 0) {
651    NewName.insert(0, 1, 'n');
652  }
653
654  // Replace illegal characters with their ASCII equivalent
655  std::string legal_elements = "_abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
656  size_t pos;
657  while ((pos = NewName.find_first_not_of(legal_elements)) != std::string::npos) {
658    char old_c = NewName.at(pos);
659    char new_str[16];
660    sprintf(new_str, "%d", (int)old_c);
661    NewName = NewName.replace(pos, 1, new_str);
662  }
663
664  return NewName;
665}
666
667//===----------------------------------------------------------------------===//
668// MCJIT object cache class
669//===----------------------------------------------------------------------===//
670
671class MCJITObjectCache : public ObjectCache {
672public:
673  MCJITObjectCache() {
674    // Set IR cache directory
675    sys::fs::current_path(CacheDir);
676    sys::path::append(CacheDir, "toy_object_cache");
677  }
678
679  virtual ~MCJITObjectCache() {
680  }
681
682  virtual void notifyObjectCompiled(const Module *M, const MemoryBuffer *Obj) {
683    // Get the ModuleID
684    const std::string ModuleID = M->getModuleIdentifier();
685
686    // If we've flagged this as an IR file, cache it
687    if (0 == ModuleID.compare(0, 3, "IR:")) {
688      std::string IRFileName = ModuleID.substr(3);
689      SmallString<128>IRCacheFile = CacheDir;
690      sys::path::append(IRCacheFile, IRFileName);
691      if (!sys::fs::exists(CacheDir.str()) && sys::fs::create_directory(CacheDir.str())) {
692        fprintf(stderr, "Unable to create cache directory\n");
693        return;
694      }
695      std::string ErrStr;
696      raw_fd_ostream IRObjectFile(IRCacheFile.c_str(), ErrStr, raw_fd_ostream::F_Binary);
697      IRObjectFile << Obj->getBuffer();
698    }
699  }
700
701  // MCJIT will call this function before compiling any module
702  // MCJIT takes ownership of both the MemoryBuffer object and the memory
703  // to which it refers.
704  virtual MemoryBuffer* getObject(const Module* M) {
705    // Get the ModuleID
706    const std::string ModuleID = M->getModuleIdentifier();
707
708    // If we've flagged this as an IR file, cache it
709    if (0 == ModuleID.compare(0, 3, "IR:")) {
710      std::string IRFileName = ModuleID.substr(3);
711      SmallString<128> IRCacheFile = CacheDir;
712      sys::path::append(IRCacheFile, IRFileName);
713      if (!sys::fs::exists(IRCacheFile.str())) {
714        // This file isn't in our cache
715        return NULL;
716      }
717      OwningPtr<MemoryBuffer> IRObjectBuffer;
718      MemoryBuffer::getFile(IRCacheFile.c_str(), IRObjectBuffer, -1, false);
719      // MCJIT will want to write into this buffer, and we don't want that
720      // because the file has probably just been mmapped.  Instead we make
721      // a copy.  The filed-based buffer will be released when it goes
722      // out of scope.
723      return MemoryBuffer::getMemBufferCopy(IRObjectBuffer->getBuffer());
724    }
725
726    return NULL;
727  }
728
729private:
730  SmallString<128> CacheDir;
731};
732
733//===----------------------------------------------------------------------===//
734// MCJIT helper class
735//===----------------------------------------------------------------------===//
736
737class MCJITHelper
738{
739public:
740  MCJITHelper(LLVMContext& C) : Context(C), OpenModule(NULL) {}
741  ~MCJITHelper();
742
743  Function *getFunction(const std::string FnName);
744  Module *getModuleForNewFunction();
745  void *getPointerToFunction(Function* F);
746  void *getPointerToNamedFunction(const std::string &Name);
747  ExecutionEngine *compileModule(Module *M);
748  void closeCurrentModule();
749  void addModule(Module *M);
750  void dump();
751
752private:
753  typedef std::vector<Module*> ModuleVector;
754
755  LLVMContext  &Context;
756  Module       *OpenModule;
757  ModuleVector  Modules;
758  std::map<Module *, ExecutionEngine *> EngineMap;
759  MCJITObjectCache OurObjectCache;
760};
761
762class HelpingMemoryManager : public SectionMemoryManager
763{
764  HelpingMemoryManager(const HelpingMemoryManager&) LLVM_DELETED_FUNCTION;
765  void operator=(const HelpingMemoryManager&) LLVM_DELETED_FUNCTION;
766
767public:
768  HelpingMemoryManager(MCJITHelper *Helper) : MasterHelper(Helper) {}
769  virtual ~HelpingMemoryManager() {}
770
771  /// This method returns the address of the specified function.
772  /// Our implementation will attempt to find functions in other
773  /// modules associated with the MCJITHelper to cross link functions
774  /// from one generated module to another.
775  ///
776  /// If \p AbortOnFailure is false and no function with the given name is
777  /// found, this function returns a null pointer. Otherwise, it prints a
778  /// message to stderr and aborts.
779  virtual void *getPointerToNamedFunction(const std::string &Name,
780                                          bool AbortOnFailure = true);
781private:
782  MCJITHelper *MasterHelper;
783};
784
785void *HelpingMemoryManager::getPointerToNamedFunction(const std::string &Name,
786                                        bool AbortOnFailure)
787{
788  // Try the standard symbol resolution first, but ask it not to abort.
789  void *pfn = SectionMemoryManager::getPointerToNamedFunction(Name, false);
790  if (pfn)
791    return pfn;
792
793  pfn = MasterHelper->getPointerToNamedFunction(Name);
794  if (!pfn && AbortOnFailure)
795    report_fatal_error("Program used external function '" + Name +
796                        "' which could not be resolved!");
797  return pfn;
798}
799
800MCJITHelper::~MCJITHelper()
801{
802  // Walk the vector of modules.
803  ModuleVector::iterator it, end;
804  for (it = Modules.begin(), end = Modules.end();
805       it != end; ++it) {
806    // See if we have an execution engine for this module.
807    std::map<Module*, ExecutionEngine*>::iterator mapIt = EngineMap.find(*it);
808    // If we have an EE, the EE owns the module so just delete the EE.
809    if (mapIt != EngineMap.end()) {
810      delete mapIt->second;
811    } else {
812      // Otherwise, we still own the module.  Delete it now.
813      delete *it;
814    }
815  }
816}
817
818Function *MCJITHelper::getFunction(const std::string FnName) {
819  ModuleVector::iterator begin = Modules.begin();
820  ModuleVector::iterator end = Modules.end();
821  ModuleVector::iterator it;
822  for (it = begin; it != end; ++it) {
823    Function *F = (*it)->getFunction(FnName);
824    if (F) {
825      if (*it == OpenModule)
826          return F;
827
828      assert(OpenModule != NULL);
829
830      // This function is in a module that has already been JITed.
831      // We need to generate a new prototype for external linkage.
832      Function *PF = OpenModule->getFunction(FnName);
833      if (PF && !PF->empty()) {
834        ErrorF("redefinition of function across modules");
835        return 0;
836      }
837
838      // If we don't have a prototype yet, create one.
839      if (!PF)
840        PF = Function::Create(F->getFunctionType(),
841                                      Function::ExternalLinkage,
842                                      FnName,
843                                      OpenModule);
844      return PF;
845    }
846  }
847  return NULL;
848}
849
850Module *MCJITHelper::getModuleForNewFunction() {
851  // If we have a Module that hasn't been JITed, use that.
852  if (OpenModule)
853    return OpenModule;
854
855  // Otherwise create a new Module.
856  std::string ModName = GenerateUniqueName("mcjit_module_");
857  Module *M = new Module(ModName, Context);
858  Modules.push_back(M);
859  OpenModule = M;
860  return M;
861}
862
863void *MCJITHelper::getPointerToFunction(Function* F) {
864  // Look for this function in an existing module
865  ModuleVector::iterator begin = Modules.begin();
866  ModuleVector::iterator end = Modules.end();
867  ModuleVector::iterator it;
868  std::string FnName = F->getName();
869  for (it = begin; it != end; ++it) {
870    Function *MF = (*it)->getFunction(FnName);
871    if (MF == F) {
872      std::map<Module*, ExecutionEngine*>::iterator eeIt = EngineMap.find(*it);
873      if (eeIt != EngineMap.end()) {
874        void *P = eeIt->second->getPointerToFunction(F);
875        if (P)
876          return P;
877      } else {
878        ExecutionEngine *EE = compileModule(*it);
879        void *P = EE->getPointerToFunction(F);
880        if (P)
881          return P;
882      }
883    }
884  }
885  return NULL;
886}
887
888void MCJITHelper::closeCurrentModule() {
889  OpenModule = NULL;
890}
891
892ExecutionEngine *MCJITHelper::compileModule(Module *M) {
893  if (M == OpenModule)
894    closeCurrentModule();
895
896  std::string ErrStr;
897  ExecutionEngine *NewEngine = EngineBuilder(M)
898                                            .setErrorStr(&ErrStr)
899                                            .setUseMCJIT(true)
900                                            .setMCJITMemoryManager(new HelpingMemoryManager(this))
901                                            .create();
902  if (!NewEngine) {
903    fprintf(stderr, "Could not create ExecutionEngine: %s\n", ErrStr.c_str());
904    exit(1);
905  }
906
907  if (UseObjectCache)
908    NewEngine->setObjectCache(&OurObjectCache);
909
910  // Get the ModuleID so we can identify IR input files
911  const std::string ModuleID = M->getModuleIdentifier();
912
913  // If we've flagged this as an IR file, it doesn't need function passes run.
914  if (0 != ModuleID.compare(0, 3, "IR:")) {
915    // Create a function pass manager for this engine
916    FunctionPassManager *FPM = new FunctionPassManager(M);
917
918    // Set up the optimizer pipeline.  Start with registering info about how the
919    // target lays out data structures.
920    FPM->add(new DataLayout(*NewEngine->getDataLayout()));
921    // Provide basic AliasAnalysis support for GVN.
922    FPM->add(createBasicAliasAnalysisPass());
923    // Promote allocas to registers.
924    FPM->add(createPromoteMemoryToRegisterPass());
925    // Do simple "peephole" optimizations and bit-twiddling optzns.
926    FPM->add(createInstructionCombiningPass());
927    // Reassociate expressions.
928    FPM->add(createReassociatePass());
929    // Eliminate Common SubExpressions.
930    FPM->add(createGVNPass());
931    // Simplify the control flow graph (deleting unreachable blocks, etc).
932    FPM->add(createCFGSimplificationPass());
933    FPM->doInitialization();
934
935    // For each function in the module
936    Module::iterator it;
937    Module::iterator end = M->end();
938    for (it = M->begin(); it != end; ++it) {
939      // Run the FPM on this function
940      FPM->run(*it);
941    }
942
943    // We don't need this anymore
944    delete FPM;
945  }
946
947  // Store this engine
948  EngineMap[M] = NewEngine;
949  NewEngine->finalizeObject();
950
951  return NewEngine;
952}
953
954void *MCJITHelper::getPointerToNamedFunction(const std::string &Name)
955{
956  // Look for the functions in our modules, compiling only as necessary
957  ModuleVector::iterator begin = Modules.begin();
958  ModuleVector::iterator end = Modules.end();
959  ModuleVector::iterator it;
960  for (it = begin; it != end; ++it) {
961    Function *F = (*it)->getFunction(Name);
962    if (F && !F->empty()) {
963      std::map<Module*, ExecutionEngine*>::iterator eeIt = EngineMap.find(*it);
964      if (eeIt != EngineMap.end()) {
965        void *P = eeIt->second->getPointerToFunction(F);
966        if (P)
967          return P;
968      } else {
969        ExecutionEngine *EE = compileModule(*it);
970        void *P = EE->getPointerToFunction(F);
971        if (P)
972          return P;
973      }
974    }
975  }
976  return NULL;
977}
978
979void MCJITHelper::addModule(Module* M) {
980  Modules.push_back(M);
981}
982
983void MCJITHelper::dump()
984{
985  ModuleVector::iterator begin = Modules.begin();
986  ModuleVector::iterator end = Modules.end();
987  ModuleVector::iterator it;
988  for (it = begin; it != end; ++it)
989    (*it)->dump();
990}
991
992//===----------------------------------------------------------------------===//
993// Code Generation
994//===----------------------------------------------------------------------===//
995
996static MCJITHelper *TheHelper;
997static IRBuilder<> Builder(getGlobalContext());
998static std::map<std::string, AllocaInst*> NamedValues;
999
1000Value *ErrorV(const char *Str) { Error(Str); return 0; }
1001
1002/// CreateEntryBlockAlloca - Create an alloca instruction in the entry block of
1003/// the function.  This is used for mutable variables etc.
1004static AllocaInst *CreateEntryBlockAlloca(Function *TheFunction,
1005                                          const std::string &VarName) {
1006  IRBuilder<> TmpB(&TheFunction->getEntryBlock(),
1007                 TheFunction->getEntryBlock().begin());
1008  return TmpB.CreateAlloca(Type::getDoubleTy(getGlobalContext()), 0,
1009                           VarName.c_str());
1010}
1011
1012Value *NumberExprAST::Codegen() {
1013  return ConstantFP::get(getGlobalContext(), APFloat(Val));
1014}
1015
1016Value *VariableExprAST::Codegen() {
1017  // Look this variable up in the function.
1018  Value *V = NamedValues[Name];
1019  char ErrStr[256];
1020  sprintf(ErrStr, "Unknown variable name %s", Name.c_str());
1021  if (V == 0) return ErrorV(ErrStr);
1022
1023  // Load the value.
1024  return Builder.CreateLoad(V, Name.c_str());
1025}
1026
1027Value *UnaryExprAST::Codegen() {
1028  Value *OperandV = Operand->Codegen();
1029  if (OperandV == 0) return 0;
1030
1031  Function *F = TheHelper->getFunction(MakeLegalFunctionName(std::string("unary")+Opcode));
1032  if (F == 0)
1033    return ErrorV("Unknown unary operator");
1034
1035  return Builder.CreateCall(F, OperandV, "unop");
1036}
1037
1038Value *BinaryExprAST::Codegen() {
1039  // Special case '=' because we don't want to emit the LHS as an expression.
1040  if (Op == '=') {
1041    // Assignment requires the LHS to be an identifier.
1042    VariableExprAST *LHSE = reinterpret_cast<VariableExprAST*>(LHS);
1043    if (!LHSE)
1044      return ErrorV("destination of '=' must be a variable");
1045    // Codegen the RHS.
1046    Value *Val = RHS->Codegen();
1047    if (Val == 0) return 0;
1048
1049    // Look up the name.
1050    Value *Variable = NamedValues[LHSE->getName()];
1051    if (Variable == 0) return ErrorV("Unknown variable name");
1052
1053    Builder.CreateStore(Val, Variable);
1054    return Val;
1055  }
1056
1057  Value *L = LHS->Codegen();
1058  Value *R = RHS->Codegen();
1059  if (L == 0 || R == 0) return 0;
1060
1061  switch (Op) {
1062  case '+': return Builder.CreateFAdd(L, R, "addtmp");
1063  case '-': return Builder.CreateFSub(L, R, "subtmp");
1064  case '*': return Builder.CreateFMul(L, R, "multmp");
1065  case '/': return Builder.CreateFDiv(L, R, "divtmp");
1066  case '<':
1067    L = Builder.CreateFCmpULT(L, R, "cmptmp");
1068    // Convert bool 0/1 to double 0.0 or 1.0
1069    return Builder.CreateUIToFP(L, Type::getDoubleTy(getGlobalContext()),
1070                                "booltmp");
1071  default: break;
1072  }
1073
1074  // If it wasn't a builtin binary operator, it must be a user defined one. Emit
1075  // a call to it.
1076  Function *F = TheHelper->getFunction(MakeLegalFunctionName(std::string("binary")+Op));
1077  assert(F && "binary operator not found!");
1078
1079  Value *Ops[] = { L, R };
1080  return Builder.CreateCall(F, Ops, "binop");
1081}
1082
1083Value *CallExprAST::Codegen() {
1084  // Look up the name in the global module table.
1085  Function *CalleeF = TheHelper->getFunction(Callee);
1086  if (CalleeF == 0)
1087    return ErrorV("Unknown function referenced");
1088
1089  // If argument mismatch error.
1090  if (CalleeF->arg_size() != Args.size())
1091    return ErrorV("Incorrect # arguments passed");
1092
1093  std::vector<Value*> ArgsV;
1094  for (unsigned i = 0, e = Args.size(); i != e; ++i) {
1095    ArgsV.push_back(Args[i]->Codegen());
1096    if (ArgsV.back() == 0) return 0;
1097  }
1098
1099  return Builder.CreateCall(CalleeF, ArgsV, "calltmp");
1100}
1101
1102Value *IfExprAST::Codegen() {
1103  Value *CondV = Cond->Codegen();
1104  if (CondV == 0) return 0;
1105
1106  // Convert condition to a bool by comparing equal to 0.0.
1107  CondV = Builder.CreateFCmpONE(CondV,
1108                              ConstantFP::get(getGlobalContext(), APFloat(0.0)),
1109                                "ifcond");
1110
1111  Function *TheFunction = Builder.GetInsertBlock()->getParent();
1112
1113  // Create blocks for the then and else cases.  Insert the 'then' block at the
1114  // end of the function.
1115  BasicBlock *ThenBB = BasicBlock::Create(getGlobalContext(), "then", TheFunction);
1116  BasicBlock *ElseBB = BasicBlock::Create(getGlobalContext(), "else");
1117  BasicBlock *MergeBB = BasicBlock::Create(getGlobalContext(), "ifcont");
1118
1119  Builder.CreateCondBr(CondV, ThenBB, ElseBB);
1120
1121  // Emit then value.
1122  Builder.SetInsertPoint(ThenBB);
1123
1124  Value *ThenV = Then->Codegen();
1125  if (ThenV == 0) return 0;
1126
1127  Builder.CreateBr(MergeBB);
1128  // Codegen of 'Then' can change the current block, update ThenBB for the PHI.
1129  ThenBB = Builder.GetInsertBlock();
1130
1131  // Emit else block.
1132  TheFunction->getBasicBlockList().push_back(ElseBB);
1133  Builder.SetInsertPoint(ElseBB);
1134
1135  Value *ElseV = Else->Codegen();
1136  if (ElseV == 0) return 0;
1137
1138  Builder.CreateBr(MergeBB);
1139  // Codegen of 'Else' can change the current block, update ElseBB for the PHI.
1140  ElseBB = Builder.GetInsertBlock();
1141
1142  // Emit merge block.
1143  TheFunction->getBasicBlockList().push_back(MergeBB);
1144  Builder.SetInsertPoint(MergeBB);
1145  PHINode *PN = Builder.CreatePHI(Type::getDoubleTy(getGlobalContext()), 2,
1146                                  "iftmp");
1147
1148  PN->addIncoming(ThenV, ThenBB);
1149  PN->addIncoming(ElseV, ElseBB);
1150  return PN;
1151}
1152
1153Value *ForExprAST::Codegen() {
1154  // Output this as:
1155  //   var = alloca double
1156  //   ...
1157  //   start = startexpr
1158  //   store start -> var
1159  //   goto loop
1160  // loop:
1161  //   ...
1162  //   bodyexpr
1163  //   ...
1164  // loopend:
1165  //   step = stepexpr
1166  //   endcond = endexpr
1167  //
1168  //   curvar = load var
1169  //   nextvar = curvar + step
1170  //   store nextvar -> var
1171  //   br endcond, loop, endloop
1172  // outloop:
1173
1174  Function *TheFunction = Builder.GetInsertBlock()->getParent();
1175
1176  // Create an alloca for the variable in the entry block.
1177  AllocaInst *Alloca = CreateEntryBlockAlloca(TheFunction, VarName);
1178
1179  // Emit the start code first, without 'variable' in scope.
1180  Value *StartVal = Start->Codegen();
1181  if (StartVal == 0) return 0;
1182
1183  // Store the value into the alloca.
1184  Builder.CreateStore(StartVal, Alloca);
1185
1186  // Make the new basic block for the loop header, inserting after current
1187  // block.
1188  BasicBlock *LoopBB = BasicBlock::Create(getGlobalContext(), "loop", TheFunction);
1189
1190  // Insert an explicit fall through from the current block to the LoopBB.
1191  Builder.CreateBr(LoopBB);
1192
1193  // Start insertion in LoopBB.
1194  Builder.SetInsertPoint(LoopBB);
1195
1196  // Within the loop, the variable is defined equal to the PHI node.  If it
1197  // shadows an existing variable, we have to restore it, so save it now.
1198  AllocaInst *OldVal = NamedValues[VarName];
1199  NamedValues[VarName] = Alloca;
1200
1201  // Emit the body of the loop.  This, like any other expr, can change the
1202  // current BB.  Note that we ignore the value computed by the body, but don't
1203  // allow an error.
1204  if (Body->Codegen() == 0)
1205    return 0;
1206
1207  // Emit the step value.
1208  Value *StepVal;
1209  if (Step) {
1210    StepVal = Step->Codegen();
1211    if (StepVal == 0) return 0;
1212  } else {
1213    // If not specified, use 1.0.
1214    StepVal = ConstantFP::get(getGlobalContext(), APFloat(1.0));
1215  }
1216
1217  // Compute the end condition.
1218  Value *EndCond = End->Codegen();
1219  if (EndCond == 0) return EndCond;
1220
1221  // Reload, increment, and restore the alloca.  This handles the case where
1222  // the body of the loop mutates the variable.
1223  Value *CurVar = Builder.CreateLoad(Alloca, VarName.c_str());
1224  Value *NextVar = Builder.CreateFAdd(CurVar, StepVal, "nextvar");
1225  Builder.CreateStore(NextVar, Alloca);
1226
1227  // Convert condition to a bool by comparing equal to 0.0.
1228  EndCond = Builder.CreateFCmpONE(EndCond,
1229                              ConstantFP::get(getGlobalContext(), APFloat(0.0)),
1230                                  "loopcond");
1231
1232  // Create the "after loop" block and insert it.
1233  BasicBlock *AfterBB = BasicBlock::Create(getGlobalContext(), "afterloop", TheFunction);
1234
1235  // Insert the conditional branch into the end of LoopEndBB.
1236  Builder.CreateCondBr(EndCond, LoopBB, AfterBB);
1237
1238  // Any new code will be inserted in AfterBB.
1239  Builder.SetInsertPoint(AfterBB);
1240
1241  // Restore the unshadowed variable.
1242  if (OldVal)
1243    NamedValues[VarName] = OldVal;
1244  else
1245    NamedValues.erase(VarName);
1246
1247
1248  // for expr always returns 0.0.
1249  return Constant::getNullValue(Type::getDoubleTy(getGlobalContext()));
1250}
1251
1252Value *VarExprAST::Codegen() {
1253  std::vector<AllocaInst *> OldBindings;
1254
1255  Function *TheFunction = Builder.GetInsertBlock()->getParent();
1256
1257  // Register all variables and emit their initializer.
1258  for (unsigned i = 0, e = VarNames.size(); i != e; ++i) {
1259    const std::string &VarName = VarNames[i].first;
1260    ExprAST *Init = VarNames[i].second;
1261
1262    // Emit the initializer before adding the variable to scope, this prevents
1263    // the initializer from referencing the variable itself, and permits stuff
1264    // like this:
1265    //  var a = 1 in
1266    //    var a = a in ...   # refers to outer 'a'.
1267    Value *InitVal;
1268    if (Init) {
1269      InitVal = Init->Codegen();
1270      if (InitVal == 0) return 0;
1271    } else { // If not specified, use 0.0.
1272      InitVal = ConstantFP::get(getGlobalContext(), APFloat(0.0));
1273    }
1274
1275    AllocaInst *Alloca = CreateEntryBlockAlloca(TheFunction, VarName);
1276    Builder.CreateStore(InitVal, Alloca);
1277
1278    // Remember the old variable binding so that we can restore the binding when
1279    // we unrecurse.
1280    OldBindings.push_back(NamedValues[VarName]);
1281
1282    // Remember this binding.
1283    NamedValues[VarName] = Alloca;
1284  }
1285
1286  // Codegen the body, now that all vars are in scope.
1287  Value *BodyVal = Body->Codegen();
1288  if (BodyVal == 0) return 0;
1289
1290  // Pop all our variables from scope.
1291  for (unsigned i = 0, e = VarNames.size(); i != e; ++i)
1292    NamedValues[VarNames[i].first] = OldBindings[i];
1293
1294  // Return the body computation.
1295  return BodyVal;
1296}
1297
1298Function *PrototypeAST::Codegen() {
1299  // Make the function type:  double(double,double) etc.
1300  std::vector<Type*> Doubles(Args.size(),
1301                             Type::getDoubleTy(getGlobalContext()));
1302  FunctionType *FT = FunctionType::get(Type::getDoubleTy(getGlobalContext()),
1303                                       Doubles, false);
1304
1305  std::string FnName = MakeLegalFunctionName(Name);
1306
1307  Module* M = TheHelper->getModuleForNewFunction();
1308
1309  Function *F = Function::Create(FT, Function::ExternalLinkage, FnName, M);
1310
1311  // If F conflicted, there was already something named 'FnName'.  If it has a
1312  // body, don't allow redefinition or reextern.
1313  if (F->getName() != FnName) {
1314    // Delete the one we just made and get the existing one.
1315    F->eraseFromParent();
1316    F = M->getFunction(Name);
1317
1318    // If F already has a body, reject this.
1319    if (!F->empty()) {
1320      ErrorF("redefinition of function");
1321      return 0;
1322    }
1323
1324    // If F took a different number of args, reject.
1325    if (F->arg_size() != Args.size()) {
1326      ErrorF("redefinition of function with different # args");
1327      return 0;
1328    }
1329  }
1330
1331  // Set names for all arguments.
1332  unsigned Idx = 0;
1333  for (Function::arg_iterator AI = F->arg_begin(); Idx != Args.size();
1334       ++AI, ++Idx)
1335    AI->setName(Args[Idx]);
1336
1337  return F;
1338}
1339
1340/// CreateArgumentAllocas - Create an alloca for each argument and register the
1341/// argument in the symbol table so that references to it will succeed.
1342void PrototypeAST::CreateArgumentAllocas(Function *F) {
1343  Function::arg_iterator AI = F->arg_begin();
1344  for (unsigned Idx = 0, e = Args.size(); Idx != e; ++Idx, ++AI) {
1345    // Create an alloca for this variable.
1346    AllocaInst *Alloca = CreateEntryBlockAlloca(F, Args[Idx]);
1347
1348    // Store the initial value into the alloca.
1349    Builder.CreateStore(AI, Alloca);
1350
1351    // Add arguments to variable symbol table.
1352    NamedValues[Args[Idx]] = Alloca;
1353  }
1354}
1355
1356Function *FunctionAST::Codegen() {
1357  NamedValues.clear();
1358
1359  Function *TheFunction = Proto->Codegen();
1360  if (TheFunction == 0)
1361    return 0;
1362
1363  // If this is an operator, install it.
1364  if (Proto->isBinaryOp())
1365    BinopPrecedence[Proto->getOperatorName()] = Proto->getBinaryPrecedence();
1366
1367  // Create a new basic block to start insertion into.
1368  BasicBlock *BB = BasicBlock::Create(getGlobalContext(), "entry", TheFunction);
1369  Builder.SetInsertPoint(BB);
1370
1371  // Add all arguments to the symbol table and create their allocas.
1372  Proto->CreateArgumentAllocas(TheFunction);
1373
1374  if (Value *RetVal = Body->Codegen()) {
1375    // Finish off the function.
1376    Builder.CreateRet(RetVal);
1377
1378    // Validate the generated code, checking for consistency.
1379    verifyFunction(*TheFunction);
1380
1381    return TheFunction;
1382  }
1383
1384  // Error reading body, remove function.
1385  TheFunction->eraseFromParent();
1386
1387  if (Proto->isBinaryOp())
1388    BinopPrecedence.erase(Proto->getOperatorName());
1389  return 0;
1390}
1391
1392//===----------------------------------------------------------------------===//
1393// Top-Level parsing and JIT Driver
1394//===----------------------------------------------------------------------===//
1395
1396static void HandleDefinition() {
1397  if (FunctionAST *F = ParseDefinition()) {
1398    TheHelper->closeCurrentModule();
1399    if (Function *LF = F->Codegen()) {
1400#ifndef MINIMAL_STDERR_OUTPUT
1401      fprintf(stderr, "Read function definition:");
1402      LF->dump();
1403#endif
1404    }
1405  } else {
1406    // Skip token for error recovery.
1407    getNextToken();
1408  }
1409}
1410
1411static void HandleExtern() {
1412  if (PrototypeAST *P = ParseExtern()) {
1413    if (Function *F = P->Codegen()) {
1414#ifndef MINIMAL_STDERR_OUTPUT
1415      fprintf(stderr, "Read extern: ");
1416      F->dump();
1417#endif
1418    }
1419  } else {
1420    // Skip token for error recovery.
1421    getNextToken();
1422  }
1423}
1424
1425static void HandleTopLevelExpression() {
1426  // Evaluate a top-level expression into an anonymous function.
1427  if (FunctionAST *F = ParseTopLevelExpr()) {
1428    if (Function *LF = F->Codegen()) {
1429      // JIT the function, returning a function pointer.
1430      void *FPtr = TheHelper->getPointerToFunction(LF);
1431
1432      // Cast it to the right type (takes no arguments, returns a double) so we
1433      // can call it as a native function.
1434      double (*FP)() = (double (*)())(intptr_t)FPtr;
1435#ifdef MINIMAL_STDERR_OUTPUT
1436      FP();
1437#else
1438      fprintf(stderr, "Evaluated to %f\n", FP());
1439#endif
1440    }
1441  } else {
1442    // Skip token for error recovery.
1443    getNextToken();
1444  }
1445}
1446
1447/// top ::= definition | external | expression | ';'
1448static void MainLoop() {
1449  while (1) {
1450#ifndef MINIMAL_STDERR_OUTPUT
1451    fprintf(stderr, "ready> ");
1452#endif
1453    switch (CurTok) {
1454    case tok_eof:    return;
1455    case ';':        getNextToken(); break;  // ignore top-level semicolons.
1456    case tok_def:    HandleDefinition(); break;
1457    case tok_extern: HandleExtern(); break;
1458    default:         HandleTopLevelExpression(); break;
1459    }
1460  }
1461}
1462
1463//===----------------------------------------------------------------------===//
1464// "Library" functions that can be "extern'd" from user code.
1465//===----------------------------------------------------------------------===//
1466
1467/// putchard - putchar that takes a double and returns 0.
1468extern "C"
1469double putchard(double X) {
1470  putchar((char)X);
1471  return 0;
1472}
1473
1474/// printd - printf that takes a double prints it as "%f\n", returning 0.
1475extern "C"
1476double printd(double X) {
1477  printf("%f", X);
1478  return 0;
1479}
1480
1481extern "C"
1482double printlf() {
1483  printf("\n");
1484  return 0;
1485}
1486
1487//===----------------------------------------------------------------------===//
1488// Command line input file handler
1489//===----------------------------------------------------------------------===//
1490
1491Module* parseInputIR(std::string InputFile) {
1492  SMDiagnostic Err;
1493  Module *M = ParseIRFile(InputFile, Err, getGlobalContext());
1494  if (!M) {
1495    Err.print("IR parsing failed: ", errs());
1496    return NULL;
1497  }
1498
1499  char ModID[256];
1500  sprintf(ModID, "IR:%s", InputFile.c_str());
1501  M->setModuleIdentifier(ModID);
1502
1503  TheHelper->addModule(M);
1504  return M;
1505}
1506
1507//===----------------------------------------------------------------------===//
1508// Main driver code.
1509//===----------------------------------------------------------------------===//
1510
1511int main(int argc, char **argv) {
1512  InitializeNativeTarget();
1513  InitializeNativeTargetAsmPrinter();
1514  InitializeNativeTargetAsmParser();
1515  LLVMContext &Context = getGlobalContext();
1516
1517  cl::ParseCommandLineOptions(argc, argv,
1518                              "Kaleidoscope example program\n");
1519
1520  // Install standard binary operators.
1521  // 1 is lowest precedence.
1522  BinopPrecedence['='] = 2;
1523  BinopPrecedence['<'] = 10;
1524  BinopPrecedence['+'] = 20;
1525  BinopPrecedence['-'] = 20;
1526  BinopPrecedence['/'] = 40;
1527  BinopPrecedence['*'] = 40;  // highest.
1528
1529  // Prime the first token.
1530#ifndef MINIMAL_STDERR_OUTPUT
1531  fprintf(stderr, "ready> ");
1532#endif
1533  getNextToken();
1534
1535  // Make the helper, which holds all the code.
1536  TheHelper = new MCJITHelper(Context);
1537
1538  if (!InputIR.empty()) {
1539    parseInputIR(InputIR);
1540  }
1541
1542  // Run the main "interpreter loop" now.
1543  MainLoop();
1544
1545#ifndef MINIMAL_STDERR_OUTPUT
1546  // Print out all of the generated code.
1547  TheHelper->dump();
1548#endif
1549
1550  return 0;
1551}
1552