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1 #include "llvm/Analysis/Passes.h"
2 #include "llvm/ExecutionEngine/ExecutionEngine.h"
3 #include "llvm/ExecutionEngine/MCJIT.h"
4 #include "llvm/ExecutionEngine/SectionMemoryManager.h"
5 #include "llvm/IR/DataLayout.h"
6 #include "llvm/IR/DerivedTypes.h"
7 #include "llvm/IR/IRBuilder.h"
8 #include "llvm/IR/LLVMContext.h"
9 #include "llvm/IR/LegacyPassManager.h"
10 #include "llvm/IR/Module.h"
11 #include "llvm/IR/Verifier.h"
12 #include "llvm/Support/TargetSelect.h"
13 #include "llvm/Transforms/Scalar.h"
14 #include <cctype>
15 #include <cstdio>
16 #include <map>
17 #include <string>
18 #include <vector>
19 using namespace llvm;
20 
21 //===----------------------------------------------------------------------===//
22 // Lexer
23 //===----------------------------------------------------------------------===//
24 
25 // The lexer returns tokens [0-255] if it is an unknown character, otherwise one
26 // of these for known things.
27 enum Token {
28   tok_eof = -1,
29 
30   // commands
31   tok_def = -2, tok_extern = -3,
32 
33   // primary
34   tok_identifier = -4, tok_number = -5,
35 
36   // control
37   tok_if = -6, tok_then = -7, tok_else = -8,
38   tok_for = -9, tok_in = -10,
39 
40   // operators
41   tok_binary = -11, tok_unary = -12,
42 
43   // var definition
44   tok_var = -13
45 };
46 
47 static std::string IdentifierStr;  // Filled in if tok_identifier
48 static double NumVal;              // Filled in if tok_number
49 
50 /// gettok - Return the next token from standard input.
gettok()51 static int gettok() {
52   static int LastChar = ' ';
53 
54   // Skip any whitespace.
55   while (isspace(LastChar))
56     LastChar = getchar();
57 
58   if (isalpha(LastChar)) { // identifier: [a-zA-Z][a-zA-Z0-9]*
59     IdentifierStr = LastChar;
60     while (isalnum((LastChar = getchar())))
61       IdentifierStr += LastChar;
62 
63     if (IdentifierStr == "def") return tok_def;
64     if (IdentifierStr == "extern") return tok_extern;
65     if (IdentifierStr == "if") return tok_if;
66     if (IdentifierStr == "then") return tok_then;
67     if (IdentifierStr == "else") return tok_else;
68     if (IdentifierStr == "for") return tok_for;
69     if (IdentifierStr == "in") return tok_in;
70     if (IdentifierStr == "binary") return tok_binary;
71     if (IdentifierStr == "unary") return tok_unary;
72     if (IdentifierStr == "var") return tok_var;
73     return tok_identifier;
74   }
75 
76   if (isdigit(LastChar) || LastChar == '.') {   // Number: [0-9.]+
77     std::string NumStr;
78     do {
79       NumStr += LastChar;
80       LastChar = getchar();
81     } while (isdigit(LastChar) || LastChar == '.');
82 
83     NumVal = strtod(NumStr.c_str(), 0);
84     return tok_number;
85   }
86 
87   if (LastChar == '#') {
88     // Comment until end of line.
89     do LastChar = getchar();
90     while (LastChar != EOF && LastChar != '\n' && LastChar != '\r');
91 
92     if (LastChar != EOF)
93       return gettok();
94   }
95 
96   // Check for end of file.  Don't eat the EOF.
97   if (LastChar == EOF)
98     return tok_eof;
99 
100   // Otherwise, just return the character as its ascii value.
101   int ThisChar = LastChar;
102   LastChar = getchar();
103   return ThisChar;
104 }
105 
106 //===----------------------------------------------------------------------===//
107 // Abstract Syntax Tree (aka Parse Tree)
108 //===----------------------------------------------------------------------===//
109 
110 /// ExprAST - Base class for all expression nodes.
111 class ExprAST {
112 public:
~ExprAST()113   virtual ~ExprAST() {}
114   virtual Value *Codegen() = 0;
115 };
116 
117 /// NumberExprAST - Expression class for numeric literals like "1.0".
118 class NumberExprAST : public ExprAST {
119   double Val;
120 public:
NumberExprAST(double val)121   NumberExprAST(double val) : Val(val) {}
122   virtual Value *Codegen();
123 };
124 
125 /// VariableExprAST - Expression class for referencing a variable, like "a".
126 class VariableExprAST : public ExprAST {
127   std::string Name;
128 public:
VariableExprAST(const std::string & name)129   VariableExprAST(const std::string &name) : Name(name) {}
getName() const130   const std::string &getName() const { return Name; }
131   virtual Value *Codegen();
132 };
133 
134 /// UnaryExprAST - Expression class for a unary operator.
135 class UnaryExprAST : public ExprAST {
136   char Opcode;
137   ExprAST *Operand;
138 public:
UnaryExprAST(char opcode,ExprAST * operand)139   UnaryExprAST(char opcode, ExprAST *operand)
140     : Opcode(opcode), Operand(operand) {}
141   virtual Value *Codegen();
142 };
143 
144 /// BinaryExprAST - Expression class for a binary operator.
145 class BinaryExprAST : public ExprAST {
146   char Op;
147   ExprAST *LHS, *RHS;
148 public:
BinaryExprAST(char op,ExprAST * lhs,ExprAST * rhs)149   BinaryExprAST(char op, ExprAST *lhs, ExprAST *rhs)
150     : Op(op), LHS(lhs), RHS(rhs) {}
151   virtual Value *Codegen();
152 };
153 
154 /// CallExprAST - Expression class for function calls.
155 class CallExprAST : public ExprAST {
156   std::string Callee;
157   std::vector<ExprAST*> Args;
158 public:
CallExprAST(const std::string & callee,std::vector<ExprAST * > & args)159   CallExprAST(const std::string &callee, std::vector<ExprAST*> &args)
160     : Callee(callee), Args(args) {}
161   virtual Value *Codegen();
162 };
163 
164 /// IfExprAST - Expression class for if/then/else.
165 class IfExprAST : public ExprAST {
166   ExprAST *Cond, *Then, *Else;
167 public:
IfExprAST(ExprAST * cond,ExprAST * then,ExprAST * _else)168   IfExprAST(ExprAST *cond, ExprAST *then, ExprAST *_else)
169   : Cond(cond), Then(then), Else(_else) {}
170   virtual Value *Codegen();
171 };
172 
173 /// ForExprAST - Expression class for for/in.
174 class ForExprAST : public ExprAST {
175   std::string VarName;
176   ExprAST *Start, *End, *Step, *Body;
177 public:
ForExprAST(const std::string & varname,ExprAST * start,ExprAST * end,ExprAST * step,ExprAST * body)178   ForExprAST(const std::string &varname, ExprAST *start, ExprAST *end,
179              ExprAST *step, ExprAST *body)
180     : VarName(varname), Start(start), End(end), Step(step), Body(body) {}
181   virtual Value *Codegen();
182 };
183 
184 /// VarExprAST - Expression class for var/in
185 class VarExprAST : public ExprAST {
186   std::vector<std::pair<std::string, ExprAST*> > VarNames;
187   ExprAST *Body;
188 public:
VarExprAST(const std::vector<std::pair<std::string,ExprAST * >> & varnames,ExprAST * body)189   VarExprAST(const std::vector<std::pair<std::string, ExprAST*> > &varnames,
190              ExprAST *body)
191   : VarNames(varnames), Body(body) {}
192 
193   virtual Value *Codegen();
194 };
195 
196 /// PrototypeAST - This class represents the "prototype" for a function,
197 /// which captures its argument names as well as if it is an operator.
198 class PrototypeAST {
199   std::string Name;
200   std::vector<std::string> Args;
201   bool isOperator;
202   unsigned Precedence;  // Precedence if a binary op.
203 public:
PrototypeAST(const std::string & name,const std::vector<std::string> & args,bool isoperator=false,unsigned prec=0)204   PrototypeAST(const std::string &name, const std::vector<std::string> &args,
205                bool isoperator = false, unsigned prec = 0)
206   : Name(name), Args(args), isOperator(isoperator), Precedence(prec) {}
207 
isUnaryOp() const208   bool isUnaryOp() const { return isOperator && Args.size() == 1; }
isBinaryOp() const209   bool isBinaryOp() const { return isOperator && Args.size() == 2; }
210 
getOperatorName() const211   char getOperatorName() const {
212     assert(isUnaryOp() || isBinaryOp());
213     return Name[Name.size()-1];
214   }
215 
getBinaryPrecedence() const216   unsigned getBinaryPrecedence() const { return Precedence; }
217 
218   Function *Codegen();
219 
220   void CreateArgumentAllocas(Function *F);
221 };
222 
223 /// FunctionAST - This class represents a function definition itself.
224 class FunctionAST {
225   PrototypeAST *Proto;
226   ExprAST *Body;
227 public:
FunctionAST(PrototypeAST * proto,ExprAST * body)228   FunctionAST(PrototypeAST *proto, ExprAST *body)
229     : Proto(proto), Body(body) {}
230 
231   Function *Codegen();
232 };
233 
234 //===----------------------------------------------------------------------===//
235 // Parser
236 //===----------------------------------------------------------------------===//
237 
238 /// CurTok/getNextToken - Provide a simple token buffer.  CurTok is the current
239 /// token the parser is looking at.  getNextToken reads another token from the
240 /// lexer and updates CurTok with its results.
241 static int CurTok;
getNextToken()242 static int getNextToken() {
243   return CurTok = gettok();
244 }
245 
246 /// BinopPrecedence - This holds the precedence for each binary operator that is
247 /// defined.
248 static std::map<char, int> BinopPrecedence;
249 
250 /// GetTokPrecedence - Get the precedence of the pending binary operator token.
GetTokPrecedence()251 static int GetTokPrecedence() {
252   if (!isascii(CurTok))
253     return -1;
254 
255   // Make sure it's a declared binop.
256   int TokPrec = BinopPrecedence[CurTok];
257   if (TokPrec <= 0) return -1;
258   return TokPrec;
259 }
260 
261 /// Error* - These are little helper functions for error handling.
Error(const char * Str)262 ExprAST *Error(const char *Str) { fprintf(stderr, "Error: %s\n", Str);return 0;}
ErrorP(const char * Str)263 PrototypeAST *ErrorP(const char *Str) { Error(Str); return 0; }
ErrorF(const char * Str)264 FunctionAST *ErrorF(const char *Str) { Error(Str); return 0; }
265 
266 static ExprAST *ParseExpression();
267 
268 /// identifierexpr
269 ///   ::= identifier
270 ///   ::= identifier '(' expression* ')'
ParseIdentifierExpr()271 static ExprAST *ParseIdentifierExpr() {
272   std::string IdName = IdentifierStr;
273 
274   getNextToken();  // eat identifier.
275 
276   if (CurTok != '(') // Simple variable ref.
277     return new VariableExprAST(IdName);
278 
279   // Call.
280   getNextToken();  // eat (
281   std::vector<ExprAST*> Args;
282   if (CurTok != ')') {
283     while (1) {
284       ExprAST *Arg = ParseExpression();
285       if (!Arg) return 0;
286       Args.push_back(Arg);
287 
288       if (CurTok == ')') break;
289 
290       if (CurTok != ',')
291         return Error("Expected ')' or ',' in argument list");
292       getNextToken();
293     }
294   }
295 
296   // Eat the ')'.
297   getNextToken();
298 
299   return new CallExprAST(IdName, Args);
300 }
301 
302 /// numberexpr ::= number
ParseNumberExpr()303 static ExprAST *ParseNumberExpr() {
304   ExprAST *Result = new NumberExprAST(NumVal);
305   getNextToken(); // consume the number
306   return Result;
307 }
308 
309 /// parenexpr ::= '(' expression ')'
ParseParenExpr()310 static ExprAST *ParseParenExpr() {
311   getNextToken();  // eat (.
312   ExprAST *V = ParseExpression();
313   if (!V) return 0;
314 
315   if (CurTok != ')')
316     return Error("expected ')'");
317   getNextToken();  // eat ).
318   return V;
319 }
320 
321 /// ifexpr ::= 'if' expression 'then' expression 'else' expression
ParseIfExpr()322 static ExprAST *ParseIfExpr() {
323   getNextToken();  // eat the if.
324 
325   // condition.
326   ExprAST *Cond = ParseExpression();
327   if (!Cond) return 0;
328 
329   if (CurTok != tok_then)
330     return Error("expected then");
331   getNextToken();  // eat the then
332 
333   ExprAST *Then = ParseExpression();
334   if (Then == 0) return 0;
335 
336   if (CurTok != tok_else)
337     return Error("expected else");
338 
339   getNextToken();
340 
341   ExprAST *Else = ParseExpression();
342   if (!Else) return 0;
343 
344   return new IfExprAST(Cond, Then, Else);
345 }
346 
347 /// forexpr ::= 'for' identifier '=' expr ',' expr (',' expr)? 'in' expression
ParseForExpr()348 static ExprAST *ParseForExpr() {
349   getNextToken();  // eat the for.
350 
351   if (CurTok != tok_identifier)
352     return Error("expected identifier after for");
353 
354   std::string IdName = IdentifierStr;
355   getNextToken();  // eat identifier.
356 
357   if (CurTok != '=')
358     return Error("expected '=' after for");
359   getNextToken();  // eat '='.
360 
361 
362   ExprAST *Start = ParseExpression();
363   if (Start == 0) return 0;
364   if (CurTok != ',')
365     return Error("expected ',' after for start value");
366   getNextToken();
367 
368   ExprAST *End = ParseExpression();
369   if (End == 0) return 0;
370 
371   // The step value is optional.
372   ExprAST *Step = 0;
373   if (CurTok == ',') {
374     getNextToken();
375     Step = ParseExpression();
376     if (Step == 0) return 0;
377   }
378 
379   if (CurTok != tok_in)
380     return Error("expected 'in' after for");
381   getNextToken();  // eat 'in'.
382 
383   ExprAST *Body = ParseExpression();
384   if (Body == 0) return 0;
385 
386   return new ForExprAST(IdName, Start, End, Step, Body);
387 }
388 
389 /// varexpr ::= 'var' identifier ('=' expression)?
390 //                    (',' identifier ('=' expression)?)* 'in' expression
ParseVarExpr()391 static ExprAST *ParseVarExpr() {
392   getNextToken();  // eat the var.
393 
394   std::vector<std::pair<std::string, ExprAST*> > VarNames;
395 
396   // At least one variable name is required.
397   if (CurTok != tok_identifier)
398     return Error("expected identifier after var");
399 
400   while (1) {
401     std::string Name = IdentifierStr;
402     getNextToken();  // eat identifier.
403 
404     // Read the optional initializer.
405     ExprAST *Init = 0;
406     if (CurTok == '=') {
407       getNextToken(); // eat the '='.
408 
409       Init = ParseExpression();
410       if (Init == 0) return 0;
411     }
412 
413     VarNames.push_back(std::make_pair(Name, Init));
414 
415     // End of var list, exit loop.
416     if (CurTok != ',') break;
417     getNextToken(); // eat the ','.
418 
419     if (CurTok != tok_identifier)
420       return Error("expected identifier list after var");
421   }
422 
423   // At this point, we have to have 'in'.
424   if (CurTok != tok_in)
425     return Error("expected 'in' keyword after 'var'");
426   getNextToken();  // eat 'in'.
427 
428   ExprAST *Body = ParseExpression();
429   if (Body == 0) return 0;
430 
431   return new VarExprAST(VarNames, Body);
432 }
433 
434 /// primary
435 ///   ::= identifierexpr
436 ///   ::= numberexpr
437 ///   ::= parenexpr
438 ///   ::= ifexpr
439 ///   ::= forexpr
440 ///   ::= varexpr
ParsePrimary()441 static ExprAST *ParsePrimary() {
442   switch (CurTok) {
443   default: return Error("unknown token when expecting an expression");
444   case tok_identifier: return ParseIdentifierExpr();
445   case tok_number:     return ParseNumberExpr();
446   case '(':            return ParseParenExpr();
447   case tok_if:         return ParseIfExpr();
448   case tok_for:        return ParseForExpr();
449   case tok_var:        return ParseVarExpr();
450   }
451 }
452 
453 /// unary
454 ///   ::= primary
455 ///   ::= '!' unary
ParseUnary()456 static ExprAST *ParseUnary() {
457   // If the current token is not an operator, it must be a primary expr.
458   if (!isascii(CurTok) || CurTok == '(' || CurTok == ',')
459     return ParsePrimary();
460 
461   // If this is a unary operator, read it.
462   int Opc = CurTok;
463   getNextToken();
464   if (ExprAST *Operand = ParseUnary())
465     return new UnaryExprAST(Opc, Operand);
466   return 0;
467 }
468 
469 /// binoprhs
470 ///   ::= ('+' unary)*
ParseBinOpRHS(int ExprPrec,ExprAST * LHS)471 static ExprAST *ParseBinOpRHS(int ExprPrec, ExprAST *LHS) {
472   // If this is a binop, find its precedence.
473   while (1) {
474     int TokPrec = GetTokPrecedence();
475 
476     // If this is a binop that binds at least as tightly as the current binop,
477     // consume it, otherwise we are done.
478     if (TokPrec < ExprPrec)
479       return LHS;
480 
481     // Okay, we know this is a binop.
482     int BinOp = CurTok;
483     getNextToken();  // eat binop
484 
485     // Parse the unary expression after the binary operator.
486     ExprAST *RHS = ParseUnary();
487     if (!RHS) return 0;
488 
489     // If BinOp binds less tightly with RHS than the operator after RHS, let
490     // the pending operator take RHS as its LHS.
491     int NextPrec = GetTokPrecedence();
492     if (TokPrec < NextPrec) {
493       RHS = ParseBinOpRHS(TokPrec+1, RHS);
494       if (RHS == 0) return 0;
495     }
496 
497     // Merge LHS/RHS.
498     LHS = new BinaryExprAST(BinOp, LHS, RHS);
499   }
500 }
501 
502 /// expression
503 ///   ::= unary binoprhs
504 ///
ParseExpression()505 static ExprAST *ParseExpression() {
506   ExprAST *LHS = ParseUnary();
507   if (!LHS) return 0;
508 
509   return ParseBinOpRHS(0, LHS);
510 }
511 
512 /// prototype
513 ///   ::= id '(' id* ')'
514 ///   ::= binary LETTER number? (id, id)
515 ///   ::= unary LETTER (id)
ParsePrototype()516 static PrototypeAST *ParsePrototype() {
517   std::string FnName;
518 
519   unsigned Kind = 0; // 0 = identifier, 1 = unary, 2 = binary.
520   unsigned BinaryPrecedence = 30;
521 
522   switch (CurTok) {
523   default:
524     return ErrorP("Expected function name in prototype");
525   case tok_identifier:
526     FnName = IdentifierStr;
527     Kind = 0;
528     getNextToken();
529     break;
530   case tok_unary:
531     getNextToken();
532     if (!isascii(CurTok))
533       return ErrorP("Expected unary operator");
534     FnName = "unary";
535     FnName += (char)CurTok;
536     Kind = 1;
537     getNextToken();
538     break;
539   case tok_binary:
540     getNextToken();
541     if (!isascii(CurTok))
542       return ErrorP("Expected binary operator");
543     FnName = "binary";
544     FnName += (char)CurTok;
545     Kind = 2;
546     getNextToken();
547 
548     // Read the precedence if present.
549     if (CurTok == tok_number) {
550       if (NumVal < 1 || NumVal > 100)
551         return ErrorP("Invalid precedecnce: must be 1..100");
552       BinaryPrecedence = (unsigned)NumVal;
553       getNextToken();
554     }
555     break;
556   }
557 
558   if (CurTok != '(')
559     return ErrorP("Expected '(' in prototype");
560 
561   std::vector<std::string> ArgNames;
562   while (getNextToken() == tok_identifier)
563     ArgNames.push_back(IdentifierStr);
564   if (CurTok != ')')
565     return ErrorP("Expected ')' in prototype");
566 
567   // success.
568   getNextToken();  // eat ')'.
569 
570   // Verify right number of names for operator.
571   if (Kind && ArgNames.size() != Kind)
572     return ErrorP("Invalid number of operands for operator");
573 
574   return new PrototypeAST(FnName, ArgNames, Kind != 0, BinaryPrecedence);
575 }
576 
577 /// definition ::= 'def' prototype expression
ParseDefinition()578 static FunctionAST *ParseDefinition() {
579   getNextToken();  // eat def.
580   PrototypeAST *Proto = ParsePrototype();
581   if (Proto == 0) return 0;
582 
583   if (ExprAST *E = ParseExpression())
584     return new FunctionAST(Proto, E);
585   return 0;
586 }
587 
588 /// toplevelexpr ::= expression
ParseTopLevelExpr()589 static FunctionAST *ParseTopLevelExpr() {
590   if (ExprAST *E = ParseExpression()) {
591     // Make an anonymous proto.
592     PrototypeAST *Proto = new PrototypeAST("", std::vector<std::string>());
593     return new FunctionAST(Proto, E);
594   }
595   return 0;
596 }
597 
598 /// external ::= 'extern' prototype
ParseExtern()599 static PrototypeAST *ParseExtern() {
600   getNextToken();  // eat extern.
601   return ParsePrototype();
602 }
603 
604 //===----------------------------------------------------------------------===//
605 // Quick and dirty hack
606 //===----------------------------------------------------------------------===//
607 
608 // FIXME: Obviously we can do better than this
GenerateUniqueName(const char * root)609 std::string GenerateUniqueName(const char *root)
610 {
611   static int i = 0;
612   char s[16];
613   sprintf(s, "%s%d", root, i++);
614   std::string S = s;
615   return S;
616 }
617 
MakeLegalFunctionName(std::string Name)618 std::string MakeLegalFunctionName(std::string Name)
619 {
620   std::string NewName;
621   if (!Name.length())
622       return GenerateUniqueName("anon_func_");
623 
624   // Start with what we have
625   NewName = Name;
626 
627   // Look for a numberic first character
628   if (NewName.find_first_of("0123456789") == 0) {
629     NewName.insert(0, 1, 'n');
630   }
631 
632   // Replace illegal characters with their ASCII equivalent
633   std::string legal_elements = "_abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
634   size_t pos;
635   while ((pos = NewName.find_first_not_of(legal_elements)) != std::string::npos) {
636     char old_c = NewName.at(pos);
637     char new_str[16];
638     sprintf(new_str, "%d", (int)old_c);
639     NewName = NewName.replace(pos, 1, new_str);
640   }
641 
642   return NewName;
643 }
644 
645 //===----------------------------------------------------------------------===//
646 // MCJIT helper class
647 //===----------------------------------------------------------------------===//
648 
649 class MCJITHelper
650 {
651 public:
MCJITHelper(LLVMContext & C)652   MCJITHelper(LLVMContext& C) : Context(C), OpenModule(NULL) {}
653   ~MCJITHelper();
654 
655   Function *getFunction(const std::string FnName);
656   Module *getModuleForNewFunction();
657   void *getPointerToFunction(Function* F);
658   void *getPointerToNamedFunction(const std::string &Name);
659   void dump();
660 
661 private:
662   typedef std::vector<Module*> ModuleVector;
663   typedef std::vector<ExecutionEngine*> EngineVector;
664 
665   LLVMContext  &Context;
666   Module       *OpenModule;
667   ModuleVector  Modules;
668   EngineVector  Engines;
669 };
670 
671 class HelpingMemoryManager : public SectionMemoryManager
672 {
673   HelpingMemoryManager(const HelpingMemoryManager&) = delete;
674   void operator=(const HelpingMemoryManager&) = delete;
675 
676 public:
HelpingMemoryManager(MCJITHelper * Helper)677   HelpingMemoryManager(MCJITHelper *Helper) : MasterHelper(Helper) {}
~HelpingMemoryManager()678   virtual ~HelpingMemoryManager() {}
679 
680   /// This method returns the address of the specified function.
681   /// Our implementation will attempt to find functions in other
682   /// modules associated with the MCJITHelper to cross link functions
683   /// from one generated module to another.
684   ///
685   /// If \p AbortOnFailure is false and no function with the given name is
686   /// found, this function returns a null pointer. Otherwise, it prints a
687   /// message to stderr and aborts.
688   virtual void *getPointerToNamedFunction(const std::string &Name,
689                                           bool AbortOnFailure = true);
690 private:
691   MCJITHelper *MasterHelper;
692 };
693 
getPointerToNamedFunction(const std::string & Name,bool AbortOnFailure)694 void *HelpingMemoryManager::getPointerToNamedFunction(const std::string &Name,
695                                         bool AbortOnFailure)
696 {
697   // Try the standard symbol resolution first, but ask it not to abort.
698   void *pfn = SectionMemoryManager::getPointerToNamedFunction(Name, false);
699   if (pfn)
700     return pfn;
701 
702   pfn = MasterHelper->getPointerToNamedFunction(Name);
703   if (!pfn && AbortOnFailure)
704     report_fatal_error("Program used external function '" + Name +
705                         "' which could not be resolved!");
706   return pfn;
707 }
708 
~MCJITHelper()709 MCJITHelper::~MCJITHelper()
710 {
711   if (OpenModule)
712     delete OpenModule;
713   EngineVector::iterator begin = Engines.begin();
714   EngineVector::iterator end = Engines.end();
715   EngineVector::iterator it;
716   for (it = begin; it != end; ++it)
717     delete *it;
718 }
719 
getFunction(const std::string FnName)720 Function *MCJITHelper::getFunction(const std::string FnName) {
721   ModuleVector::iterator begin = Modules.begin();
722   ModuleVector::iterator end = Modules.end();
723   ModuleVector::iterator it;
724   for (it = begin; it != end; ++it) {
725     Function *F = (*it)->getFunction(FnName);
726     if (F) {
727       if (*it == OpenModule)
728           return F;
729 
730       assert(OpenModule != NULL);
731 
732       // This function is in a module that has already been JITed.
733       // We need to generate a new prototype for external linkage.
734       Function *PF = OpenModule->getFunction(FnName);
735       if (PF && !PF->empty()) {
736         ErrorF("redefinition of function across modules");
737         return 0;
738       }
739 
740       // If we don't have a prototype yet, create one.
741       if (!PF)
742         PF = Function::Create(F->getFunctionType(),
743                                       Function::ExternalLinkage,
744                                       FnName,
745                                       OpenModule);
746       return PF;
747     }
748   }
749   return NULL;
750 }
751 
getModuleForNewFunction()752 Module *MCJITHelper::getModuleForNewFunction() {
753   // If we have a Module that hasn't been JITed, use that.
754   if (OpenModule)
755     return OpenModule;
756 
757   // Otherwise create a new Module.
758   std::string ModName = GenerateUniqueName("mcjit_module_");
759   Module *M = new Module(ModName, Context);
760   Modules.push_back(M);
761   OpenModule = M;
762   return M;
763 }
764 
getPointerToFunction(Function * F)765 void *MCJITHelper::getPointerToFunction(Function* F) {
766   // See if an existing instance of MCJIT has this function.
767   EngineVector::iterator begin = Engines.begin();
768   EngineVector::iterator end = Engines.end();
769   EngineVector::iterator it;
770   for (it = begin; it != end; ++it) {
771     void *P = (*it)->getPointerToFunction(F);
772     if (P)
773       return P;
774   }
775 
776   // If we didn't find the function, see if we can generate it.
777   if (OpenModule) {
778     std::string ErrStr;
779     ExecutionEngine *NewEngine = EngineBuilder(OpenModule)
780                                               .setErrorStr(&ErrStr)
781                                               .setMCJITMemoryManager(new HelpingMemoryManager(this))
782                                               .create();
783     if (!NewEngine) {
784       fprintf(stderr, "Could not create ExecutionEngine: %s\n", ErrStr.c_str());
785       exit(1);
786     }
787 
788     // Create a function pass manager for this engine
789     FunctionPassManager *FPM = new FunctionPassManager(OpenModule);
790 
791     // Set up the optimizer pipeline.  Start with registering info about how the
792     // target lays out data structures.
793     FPM->add(new DataLayout(*NewEngine->getDataLayout()));
794     // Provide basic AliasAnalysis support for GVN.
795     FPM->add(createBasicAliasAnalysisPass());
796     // Promote allocas to registers.
797     FPM->add(createPromoteMemoryToRegisterPass());
798     // Do simple "peephole" optimizations and bit-twiddling optzns.
799     FPM->add(createInstructionCombiningPass());
800     // Reassociate expressions.
801     FPM->add(createReassociatePass());
802     // Eliminate Common SubExpressions.
803     FPM->add(createGVNPass());
804     // Simplify the control flow graph (deleting unreachable blocks, etc).
805     FPM->add(createCFGSimplificationPass());
806     FPM->doInitialization();
807 
808     // For each function in the module
809     Module::iterator it;
810     Module::iterator end = OpenModule->end();
811     for (it = OpenModule->begin(); it != end; ++it) {
812       // Run the FPM on this function
813       FPM->run(*it);
814     }
815 
816     // We don't need this anymore
817     delete FPM;
818 
819     OpenModule = NULL;
820     Engines.push_back(NewEngine);
821     NewEngine->finalizeObject();
822     return NewEngine->getPointerToFunction(F);
823   }
824   return NULL;
825 }
826 
getPointerToNamedFunction(const std::string & Name)827 void *MCJITHelper::getPointerToNamedFunction(const std::string &Name)
828 {
829   // Look for the function in each of our execution engines.
830   EngineVector::iterator begin = Engines.begin();
831   EngineVector::iterator end = Engines.end();
832   EngineVector::iterator it;
833   for (it = begin; it != end; ++it) {
834     if (Function *F = (*it)->FindFunctionNamed(Name.c_str()))
835         return (*it)->getPointerToFunction(F);
836   }
837 
838   return NULL;
839 }
840 
dump()841 void MCJITHelper::dump()
842 {
843   ModuleVector::iterator begin = Modules.begin();
844   ModuleVector::iterator end = Modules.end();
845   ModuleVector::iterator it;
846   for (it = begin; it != end; ++it)
847     (*it)->dump();
848 }
849 
850 //===----------------------------------------------------------------------===//
851 // Code Generation
852 //===----------------------------------------------------------------------===//
853 
854 static MCJITHelper *TheHelper;
855 static IRBuilder<> Builder(getGlobalContext());
856 static std::map<std::string, AllocaInst*> NamedValues;
857 
ErrorV(const char * Str)858 Value *ErrorV(const char *Str) { Error(Str); return 0; }
859 
860 /// CreateEntryBlockAlloca - Create an alloca instruction in the entry block of
861 /// the function.  This is used for mutable variables etc.
CreateEntryBlockAlloca(Function * TheFunction,const std::string & VarName)862 static AllocaInst *CreateEntryBlockAlloca(Function *TheFunction,
863                                           const std::string &VarName) {
864   IRBuilder<> TmpB(&TheFunction->getEntryBlock(),
865                  TheFunction->getEntryBlock().begin());
866   return TmpB.CreateAlloca(Type::getDoubleTy(getGlobalContext()), 0,
867                            VarName.c_str());
868 }
869 
Codegen()870 Value *NumberExprAST::Codegen() {
871   return ConstantFP::get(getGlobalContext(), APFloat(Val));
872 }
873 
Codegen()874 Value *VariableExprAST::Codegen() {
875   // Look this variable up in the function.
876   Value *V = NamedValues[Name];
877   char ErrStr[256];
878   sprintf(ErrStr, "Unknown variable name %s", Name.c_str());
879   if (V == 0) return ErrorV(ErrStr);
880 
881   // Load the value.
882   return Builder.CreateLoad(V, Name.c_str());
883 }
884 
Codegen()885 Value *UnaryExprAST::Codegen() {
886   Value *OperandV = Operand->Codegen();
887   if (OperandV == 0) return 0;
888 
889   Function *F = TheHelper->getFunction(MakeLegalFunctionName(std::string("unary")+Opcode));
890   if (F == 0)
891     return ErrorV("Unknown unary operator");
892 
893   return Builder.CreateCall(F, OperandV, "unop");
894 }
895 
Codegen()896 Value *BinaryExprAST::Codegen() {
897   // Special case '=' because we don't want to emit the LHS as an expression.
898   if (Op == '=') {
899     // Assignment requires the LHS to be an identifier.
900     VariableExprAST *LHSE = static_cast<VariableExprAST*>(LHS);
901     if (!LHSE)
902       return ErrorV("destination of '=' must be a variable");
903     // Codegen the RHS.
904     Value *Val = RHS->Codegen();
905     if (Val == 0) return 0;
906 
907     // Look up the name.
908     Value *Variable = NamedValues[LHSE->getName()];
909     if (Variable == 0) return ErrorV("Unknown variable name");
910 
911     Builder.CreateStore(Val, Variable);
912     return Val;
913   }
914 
915   Value *L = LHS->Codegen();
916   Value *R = RHS->Codegen();
917   if (L == 0 || R == 0) return 0;
918 
919   switch (Op) {
920   case '+': return Builder.CreateFAdd(L, R, "addtmp");
921   case '-': return Builder.CreateFSub(L, R, "subtmp");
922   case '*': return Builder.CreateFMul(L, R, "multmp");
923   case '/': return Builder.CreateFDiv(L, R, "divtmp");
924   case '<':
925     L = Builder.CreateFCmpULT(L, R, "cmptmp");
926     // Convert bool 0/1 to double 0.0 or 1.0
927     return Builder.CreateUIToFP(L, Type::getDoubleTy(getGlobalContext()),
928                                 "booltmp");
929   default: break;
930   }
931 
932   // If it wasn't a builtin binary operator, it must be a user defined one. Emit
933   // a call to it.
934   Function *F = TheHelper->getFunction(MakeLegalFunctionName(std::string("binary")+Op));
935   assert(F && "binary operator not found!");
936 
937   Value *Ops[] = { L, R };
938   return Builder.CreateCall(F, Ops, "binop");
939 }
940 
Codegen()941 Value *CallExprAST::Codegen() {
942   // Look up the name in the global module table.
943   Function *CalleeF = TheHelper->getFunction(Callee);
944   if (CalleeF == 0)
945     return ErrorV("Unknown function referenced");
946 
947   // If argument mismatch error.
948   if (CalleeF->arg_size() != Args.size())
949     return ErrorV("Incorrect # arguments passed");
950 
951   std::vector<Value*> ArgsV;
952   for (unsigned i = 0, e = Args.size(); i != e; ++i) {
953     ArgsV.push_back(Args[i]->Codegen());
954     if (ArgsV.back() == 0) return 0;
955   }
956 
957   return Builder.CreateCall(CalleeF, ArgsV, "calltmp");
958 }
959 
Codegen()960 Value *IfExprAST::Codegen() {
961   Value *CondV = Cond->Codegen();
962   if (CondV == 0) return 0;
963 
964   // Convert condition to a bool by comparing equal to 0.0.
965   CondV = Builder.CreateFCmpONE(CondV,
966                               ConstantFP::get(getGlobalContext(), APFloat(0.0)),
967                                 "ifcond");
968 
969   Function *TheFunction = Builder.GetInsertBlock()->getParent();
970 
971   // Create blocks for the then and else cases.  Insert the 'then' block at the
972   // end of the function.
973   BasicBlock *ThenBB = BasicBlock::Create(getGlobalContext(), "then", TheFunction);
974   BasicBlock *ElseBB = BasicBlock::Create(getGlobalContext(), "else");
975   BasicBlock *MergeBB = BasicBlock::Create(getGlobalContext(), "ifcont");
976 
977   Builder.CreateCondBr(CondV, ThenBB, ElseBB);
978 
979   // Emit then value.
980   Builder.SetInsertPoint(ThenBB);
981 
982   Value *ThenV = Then->Codegen();
983   if (ThenV == 0) return 0;
984 
985   Builder.CreateBr(MergeBB);
986   // Codegen of 'Then' can change the current block, update ThenBB for the PHI.
987   ThenBB = Builder.GetInsertBlock();
988 
989   // Emit else block.
990   TheFunction->getBasicBlockList().push_back(ElseBB);
991   Builder.SetInsertPoint(ElseBB);
992 
993   Value *ElseV = Else->Codegen();
994   if (ElseV == 0) return 0;
995 
996   Builder.CreateBr(MergeBB);
997   // Codegen of 'Else' can change the current block, update ElseBB for the PHI.
998   ElseBB = Builder.GetInsertBlock();
999 
1000   // Emit merge block.
1001   TheFunction->getBasicBlockList().push_back(MergeBB);
1002   Builder.SetInsertPoint(MergeBB);
1003   PHINode *PN = Builder.CreatePHI(Type::getDoubleTy(getGlobalContext()), 2,
1004                                   "iftmp");
1005 
1006   PN->addIncoming(ThenV, ThenBB);
1007   PN->addIncoming(ElseV, ElseBB);
1008   return PN;
1009 }
1010 
Codegen()1011 Value *ForExprAST::Codegen() {
1012   // Output this as:
1013   //   var = alloca double
1014   //   ...
1015   //   start = startexpr
1016   //   store start -> var
1017   //   goto loop
1018   // loop:
1019   //   ...
1020   //   bodyexpr
1021   //   ...
1022   // loopend:
1023   //   step = stepexpr
1024   //   endcond = endexpr
1025   //
1026   //   curvar = load var
1027   //   nextvar = curvar + step
1028   //   store nextvar -> var
1029   //   br endcond, loop, endloop
1030   // outloop:
1031 
1032   Function *TheFunction = Builder.GetInsertBlock()->getParent();
1033 
1034   // Create an alloca for the variable in the entry block.
1035   AllocaInst *Alloca = CreateEntryBlockAlloca(TheFunction, VarName);
1036 
1037   // Emit the start code first, without 'variable' in scope.
1038   Value *StartVal = Start->Codegen();
1039   if (StartVal == 0) return 0;
1040 
1041   // Store the value into the alloca.
1042   Builder.CreateStore(StartVal, Alloca);
1043 
1044   // Make the new basic block for the loop header, inserting after current
1045   // block.
1046   BasicBlock *LoopBB = BasicBlock::Create(getGlobalContext(), "loop", TheFunction);
1047 
1048   // Insert an explicit fall through from the current block to the LoopBB.
1049   Builder.CreateBr(LoopBB);
1050 
1051   // Start insertion in LoopBB.
1052   Builder.SetInsertPoint(LoopBB);
1053 
1054   // Within the loop, the variable is defined equal to the PHI node.  If it
1055   // shadows an existing variable, we have to restore it, so save it now.
1056   AllocaInst *OldVal = NamedValues[VarName];
1057   NamedValues[VarName] = Alloca;
1058 
1059   // Emit the body of the loop.  This, like any other expr, can change the
1060   // current BB.  Note that we ignore the value computed by the body, but don't
1061   // allow an error.
1062   if (Body->Codegen() == 0)
1063     return 0;
1064 
1065   // Emit the step value.
1066   Value *StepVal;
1067   if (Step) {
1068     StepVal = Step->Codegen();
1069     if (StepVal == 0) return 0;
1070   } else {
1071     // If not specified, use 1.0.
1072     StepVal = ConstantFP::get(getGlobalContext(), APFloat(1.0));
1073   }
1074 
1075   // Compute the end condition.
1076   Value *EndCond = End->Codegen();
1077   if (EndCond == 0) return EndCond;
1078 
1079   // Reload, increment, and restore the alloca.  This handles the case where
1080   // the body of the loop mutates the variable.
1081   Value *CurVar = Builder.CreateLoad(Alloca, VarName.c_str());
1082   Value *NextVar = Builder.CreateFAdd(CurVar, StepVal, "nextvar");
1083   Builder.CreateStore(NextVar, Alloca);
1084 
1085   // Convert condition to a bool by comparing equal to 0.0.
1086   EndCond = Builder.CreateFCmpONE(EndCond,
1087                               ConstantFP::get(getGlobalContext(), APFloat(0.0)),
1088                                   "loopcond");
1089 
1090   // Create the "after loop" block and insert it.
1091   BasicBlock *AfterBB = BasicBlock::Create(getGlobalContext(), "afterloop", TheFunction);
1092 
1093   // Insert the conditional branch into the end of LoopEndBB.
1094   Builder.CreateCondBr(EndCond, LoopBB, AfterBB);
1095 
1096   // Any new code will be inserted in AfterBB.
1097   Builder.SetInsertPoint(AfterBB);
1098 
1099   // Restore the unshadowed variable.
1100   if (OldVal)
1101     NamedValues[VarName] = OldVal;
1102   else
1103     NamedValues.erase(VarName);
1104 
1105 
1106   // for expr always returns 0.0.
1107   return Constant::getNullValue(Type::getDoubleTy(getGlobalContext()));
1108 }
1109 
Codegen()1110 Value *VarExprAST::Codegen() {
1111   std::vector<AllocaInst *> OldBindings;
1112 
1113   Function *TheFunction = Builder.GetInsertBlock()->getParent();
1114 
1115   // Register all variables and emit their initializer.
1116   for (unsigned i = 0, e = VarNames.size(); i != e; ++i) {
1117     const std::string &VarName = VarNames[i].first;
1118     ExprAST *Init = VarNames[i].second;
1119 
1120     // Emit the initializer before adding the variable to scope, this prevents
1121     // the initializer from referencing the variable itself, and permits stuff
1122     // like this:
1123     //  var a = 1 in
1124     //    var a = a in ...   # refers to outer 'a'.
1125     Value *InitVal;
1126     if (Init) {
1127       InitVal = Init->Codegen();
1128       if (InitVal == 0) return 0;
1129     } else { // If not specified, use 0.0.
1130       InitVal = ConstantFP::get(getGlobalContext(), APFloat(0.0));
1131     }
1132 
1133     AllocaInst *Alloca = CreateEntryBlockAlloca(TheFunction, VarName);
1134     Builder.CreateStore(InitVal, Alloca);
1135 
1136     // Remember the old variable binding so that we can restore the binding when
1137     // we unrecurse.
1138     OldBindings.push_back(NamedValues[VarName]);
1139 
1140     // Remember this binding.
1141     NamedValues[VarName] = Alloca;
1142   }
1143 
1144   // Codegen the body, now that all vars are in scope.
1145   Value *BodyVal = Body->Codegen();
1146   if (BodyVal == 0) return 0;
1147 
1148   // Pop all our variables from scope.
1149   for (unsigned i = 0, e = VarNames.size(); i != e; ++i)
1150     NamedValues[VarNames[i].first] = OldBindings[i];
1151 
1152   // Return the body computation.
1153   return BodyVal;
1154 }
1155 
Codegen()1156 Function *PrototypeAST::Codegen() {
1157   // Make the function type:  double(double,double) etc.
1158   std::vector<Type*> Doubles(Args.size(),
1159                              Type::getDoubleTy(getGlobalContext()));
1160   FunctionType *FT = FunctionType::get(Type::getDoubleTy(getGlobalContext()),
1161                                        Doubles, false);
1162 
1163   std::string FnName = MakeLegalFunctionName(Name);
1164 
1165   Module* M = TheHelper->getModuleForNewFunction();
1166 
1167   Function *F = Function::Create(FT, Function::ExternalLinkage, FnName, M);
1168 
1169   // If F conflicted, there was already something named 'FnName'.  If it has a
1170   // body, don't allow redefinition or reextern.
1171   if (F->getName() != FnName) {
1172     // Delete the one we just made and get the existing one.
1173     F->eraseFromParent();
1174     F = M->getFunction(Name);
1175 
1176     // If F already has a body, reject this.
1177     if (!F->empty()) {
1178       ErrorF("redefinition of function");
1179       return 0;
1180     }
1181 
1182     // If F took a different number of args, reject.
1183     if (F->arg_size() != Args.size()) {
1184       ErrorF("redefinition of function with different # args");
1185       return 0;
1186     }
1187   }
1188 
1189   // Set names for all arguments.
1190   unsigned Idx = 0;
1191   for (Function::arg_iterator AI = F->arg_begin(); Idx != Args.size();
1192        ++AI, ++Idx)
1193     AI->setName(Args[Idx]);
1194 
1195   return F;
1196 }
1197 
1198 /// CreateArgumentAllocas - Create an alloca for each argument and register the
1199 /// argument in the symbol table so that references to it will succeed.
CreateArgumentAllocas(Function * F)1200 void PrototypeAST::CreateArgumentAllocas(Function *F) {
1201   Function::arg_iterator AI = F->arg_begin();
1202   for (unsigned Idx = 0, e = Args.size(); Idx != e; ++Idx, ++AI) {
1203     // Create an alloca for this variable.
1204     AllocaInst *Alloca = CreateEntryBlockAlloca(F, Args[Idx]);
1205 
1206     // Store the initial value into the alloca.
1207     Builder.CreateStore(AI, Alloca);
1208 
1209     // Add arguments to variable symbol table.
1210     NamedValues[Args[Idx]] = Alloca;
1211   }
1212 }
1213 
Codegen()1214 Function *FunctionAST::Codegen() {
1215   NamedValues.clear();
1216 
1217   Function *TheFunction = Proto->Codegen();
1218   if (TheFunction == 0)
1219     return 0;
1220 
1221   // If this is an operator, install it.
1222   if (Proto->isBinaryOp())
1223     BinopPrecedence[Proto->getOperatorName()] = Proto->getBinaryPrecedence();
1224 
1225   // Create a new basic block to start insertion into.
1226   BasicBlock *BB = BasicBlock::Create(getGlobalContext(), "entry", TheFunction);
1227   Builder.SetInsertPoint(BB);
1228 
1229   // Add all arguments to the symbol table and create their allocas.
1230   Proto->CreateArgumentAllocas(TheFunction);
1231 
1232   if (Value *RetVal = Body->Codegen()) {
1233     // Finish off the function.
1234     Builder.CreateRet(RetVal);
1235 
1236     // Validate the generated code, checking for consistency.
1237     verifyFunction(*TheFunction);
1238 
1239     return TheFunction;
1240   }
1241 
1242   // Error reading body, remove function.
1243   TheFunction->eraseFromParent();
1244 
1245   if (Proto->isBinaryOp())
1246     BinopPrecedence.erase(Proto->getOperatorName());
1247   return 0;
1248 }
1249 
1250 //===----------------------------------------------------------------------===//
1251 // Top-Level parsing and JIT Driver
1252 //===----------------------------------------------------------------------===//
1253 
HandleDefinition()1254 static void HandleDefinition() {
1255   if (FunctionAST *F = ParseDefinition()) {
1256     if (Function *LF = F->Codegen()) {
1257 #ifndef MINIMAL_STDERR_OUTPUT
1258       fprintf(stderr, "Read function definition:");
1259       LF->dump();
1260 #endif
1261     }
1262   } else {
1263     // Skip token for error recovery.
1264     getNextToken();
1265   }
1266 }
1267 
HandleExtern()1268 static void HandleExtern() {
1269   if (PrototypeAST *P = ParseExtern()) {
1270     if (Function *F = P->Codegen()) {
1271 #ifndef MINIMAL_STDERR_OUTPUT
1272       fprintf(stderr, "Read extern: ");
1273       F->dump();
1274 #endif
1275     }
1276   } else {
1277     // Skip token for error recovery.
1278     getNextToken();
1279   }
1280 }
1281 
HandleTopLevelExpression()1282 static void HandleTopLevelExpression() {
1283   // Evaluate a top-level expression into an anonymous function.
1284   if (FunctionAST *F = ParseTopLevelExpr()) {
1285     if (Function *LF = F->Codegen()) {
1286       // JIT the function, returning a function pointer.
1287       void *FPtr = TheHelper->getPointerToFunction(LF);
1288 
1289       // Cast it to the right type (takes no arguments, returns a double) so we
1290       // can call it as a native function.
1291       double (*FP)() = (double (*)())(intptr_t)FPtr;
1292 #ifdef MINIMAL_STDERR_OUTPUT
1293       FP();
1294 #else
1295       fprintf(stderr, "Evaluated to %f\n", FP());
1296 #endif
1297     }
1298   } else {
1299     // Skip token for error recovery.
1300     getNextToken();
1301   }
1302 }
1303 
1304 /// top ::= definition | external | expression | ';'
MainLoop()1305 static void MainLoop() {
1306   while (1) {
1307 #ifndef MINIMAL_STDERR_OUTPUT
1308     fprintf(stderr, "ready> ");
1309 #endif
1310     switch (CurTok) {
1311     case tok_eof:    return;
1312     case ';':        getNextToken(); break;  // ignore top-level semicolons.
1313     case tok_def:    HandleDefinition(); break;
1314     case tok_extern: HandleExtern(); break;
1315     default:         HandleTopLevelExpression(); break;
1316     }
1317   }
1318 }
1319 
1320 //===----------------------------------------------------------------------===//
1321 // "Library" functions that can be "extern'd" from user code.
1322 //===----------------------------------------------------------------------===//
1323 
1324 /// putchard - putchar that takes a double and returns 0.
1325 extern "C"
putchard(double X)1326 double putchard(double X) {
1327   putchar((char)X);
1328   return 0;
1329 }
1330 
1331 /// printd - printf that takes a double prints it as "%f\n", returning 0.
1332 extern "C"
printd(double X)1333 double printd(double X) {
1334   printf("%f", X);
1335   return 0;
1336 }
1337 
1338 extern "C"
printlf()1339 double printlf() {
1340   printf("\n");
1341   return 0;
1342 }
1343 
1344 //===----------------------------------------------------------------------===//
1345 // Main driver code.
1346 //===----------------------------------------------------------------------===//
1347 
main()1348 int main() {
1349   InitializeNativeTarget();
1350   InitializeNativeTargetAsmPrinter();
1351   InitializeNativeTargetAsmParser();
1352   LLVMContext &Context = getGlobalContext();
1353 
1354   // Install standard binary operators.
1355   // 1 is lowest precedence.
1356   BinopPrecedence['='] = 2;
1357   BinopPrecedence['<'] = 10;
1358   BinopPrecedence['+'] = 20;
1359   BinopPrecedence['-'] = 20;
1360   BinopPrecedence['/'] = 40;
1361   BinopPrecedence['*'] = 40;  // highest.
1362 
1363   // Prime the first token.
1364 #ifndef MINIMAL_STDERR_OUTPUT
1365   fprintf(stderr, "ready> ");
1366 #endif
1367   getNextToken();
1368 
1369   // Make the helper, which holds all the code.
1370   TheHelper = new MCJITHelper(Context);
1371 
1372   // Run the main "interpreter loop" now.
1373   MainLoop();
1374 
1375 #ifndef MINIMAL_STDERR_OUTPUT
1376   // Print out all of the generated code.
1377   TheHelper->dump();
1378 #endif
1379 
1380   return 0;
1381 }
1382