1#include "llvm/Analysis/Passes.h"
2#include "llvm/ExecutionEngine/ExecutionEngine.h"
3#include "llvm/ExecutionEngine/MCJIT.h"
4#include "llvm/ExecutionEngine/ObjectCache.h"
5#include "llvm/ExecutionEngine/SectionMemoryManager.h"
6#include "llvm/IR/DataLayout.h"
7#include "llvm/IR/DerivedTypes.h"
8#include "llvm/IR/IRBuilder.h"
9#include "llvm/IR/LLVMContext.h"
10#include "llvm/IR/LegacyPassManager.h"
11#include "llvm/IR/Module.h"
12#include "llvm/IR/Verifier.h"
13#include "llvm/IRReader/IRReader.h"
14#include "llvm/Support/CommandLine.h"
15#include "llvm/Support/FileSystem.h"
16#include "llvm/Support/Path.h"
17#include "llvm/Support/SourceMgr.h"
18#include "llvm/Support/TargetSelect.h"
19#include "llvm/Support/raw_ostream.h"
20#include "llvm/Transforms/Scalar.h"
21#include <cctype>
22#include <cstdio>
23#include <map>
24#include <string>
25#include <vector>
26
27using namespace llvm;
28
29//===----------------------------------------------------------------------===//
30// Command-line options
31//===----------------------------------------------------------------------===//
32
33namespace {
34  cl::opt<std::string>
35  InputIR("input-IR",
36              cl::desc("Specify the name of an IR file to load for function definitions"),
37              cl::value_desc("input IR file name"));
38
39  cl::opt<bool>
40  VerboseOutput("verbose",
41                cl::desc("Enable verbose output (results, IR, etc.) to stderr"),
42                cl::init(false));
43
44  cl::opt<bool>
45  SuppressPrompts("suppress-prompts",
46                  cl::desc("Disable printing the 'ready' prompt"),
47                  cl::init(false));
48
49  cl::opt<bool>
50  DumpModulesOnExit("dump-modules",
51                  cl::desc("Dump IR from modules to stderr on shutdown"),
52                  cl::init(false));
53
54  cl::opt<bool> EnableLazyCompilation(
55    "enable-lazy-compilation", cl::desc("Enable lazy compilation when using the MCJIT engine"),
56    cl::init(true));
57
58  cl::opt<bool> UseObjectCache(
59    "use-object-cache", cl::desc("Enable use of the MCJIT object caching"),
60    cl::init(false));
61} // namespace
62
63//===----------------------------------------------------------------------===//
64// Lexer
65//===----------------------------------------------------------------------===//
66
67// The lexer returns tokens [0-255] if it is an unknown character, otherwise one
68// of these for known things.
69enum Token {
70  tok_eof = -1,
71
72  // commands
73  tok_def = -2, tok_extern = -3,
74
75  // primary
76  tok_identifier = -4, tok_number = -5,
77
78  // control
79  tok_if = -6, tok_then = -7, tok_else = -8,
80  tok_for = -9, tok_in = -10,
81
82  // operators
83  tok_binary = -11, tok_unary = -12,
84
85  // var definition
86  tok_var = -13
87};
88
89static std::string IdentifierStr;  // Filled in if tok_identifier
90static double NumVal;              // Filled in if tok_number
91
92/// gettok - Return the next token from standard input.
93static int gettok() {
94  static int LastChar = ' ';
95
96  // Skip any whitespace.
97  while (isspace(LastChar))
98    LastChar = getchar();
99
100  if (isalpha(LastChar)) { // identifier: [a-zA-Z][a-zA-Z0-9]*
101    IdentifierStr = LastChar;
102    while (isalnum((LastChar = getchar())))
103      IdentifierStr += LastChar;
104
105    if (IdentifierStr == "def") return tok_def;
106    if (IdentifierStr == "extern") return tok_extern;
107    if (IdentifierStr == "if") return tok_if;
108    if (IdentifierStr == "then") return tok_then;
109    if (IdentifierStr == "else") return tok_else;
110    if (IdentifierStr == "for") return tok_for;
111    if (IdentifierStr == "in") return tok_in;
112    if (IdentifierStr == "binary") return tok_binary;
113    if (IdentifierStr == "unary") return tok_unary;
114    if (IdentifierStr == "var") return tok_var;
115    return tok_identifier;
116  }
117
118  if (isdigit(LastChar) || LastChar == '.') {   // Number: [0-9.]+
119    std::string NumStr;
120    do {
121      NumStr += LastChar;
122      LastChar = getchar();
123    } while (isdigit(LastChar) || LastChar == '.');
124
125    NumVal = strtod(NumStr.c_str(), 0);
126    return tok_number;
127  }
128
129  if (LastChar == '#') {
130    // Comment until end of line.
131    do LastChar = getchar();
132    while (LastChar != EOF && LastChar != '\n' && LastChar != '\r');
133
134    if (LastChar != EOF)
135      return gettok();
136  }
137
138  // Check for end of file.  Don't eat the EOF.
139  if (LastChar == EOF)
140    return tok_eof;
141
142  // Otherwise, just return the character as its ascii value.
143  int ThisChar = LastChar;
144  LastChar = getchar();
145  return ThisChar;
146}
147
148//===----------------------------------------------------------------------===//
149// Abstract Syntax Tree (aka Parse Tree)
150//===----------------------------------------------------------------------===//
151
152/// ExprAST - Base class for all expression nodes.
153class ExprAST {
154public:
155  virtual ~ExprAST() {}
156  virtual Value *Codegen() = 0;
157};
158
159/// NumberExprAST - Expression class for numeric literals like "1.0".
160class NumberExprAST : public ExprAST {
161  double Val;
162public:
163  NumberExprAST(double val) : Val(val) {}
164  virtual Value *Codegen();
165};
166
167/// VariableExprAST - Expression class for referencing a variable, like "a".
168class VariableExprAST : public ExprAST {
169  std::string Name;
170public:
171  VariableExprAST(const std::string &name) : Name(name) {}
172  const std::string &getName() const { return Name; }
173  virtual Value *Codegen();
174};
175
176/// UnaryExprAST - Expression class for a unary operator.
177class UnaryExprAST : public ExprAST {
178  char Opcode;
179  ExprAST *Operand;
180public:
181  UnaryExprAST(char opcode, ExprAST *operand)
182    : Opcode(opcode), Operand(operand) {}
183  virtual Value *Codegen();
184};
185
186/// BinaryExprAST - Expression class for a binary operator.
187class BinaryExprAST : public ExprAST {
188  char Op;
189  ExprAST *LHS, *RHS;
190public:
191  BinaryExprAST(char op, ExprAST *lhs, ExprAST *rhs)
192    : Op(op), LHS(lhs), RHS(rhs) {}
193  virtual Value *Codegen();
194};
195
196/// CallExprAST - Expression class for function calls.
197class CallExprAST : public ExprAST {
198  std::string Callee;
199  std::vector<ExprAST*> Args;
200public:
201  CallExprAST(const std::string &callee, std::vector<ExprAST*> &args)
202    : Callee(callee), Args(args) {}
203  virtual Value *Codegen();
204};
205
206/// IfExprAST - Expression class for if/then/else.
207class IfExprAST : public ExprAST {
208  ExprAST *Cond, *Then, *Else;
209public:
210  IfExprAST(ExprAST *cond, ExprAST *then, ExprAST *_else)
211  : Cond(cond), Then(then), Else(_else) {}
212  virtual Value *Codegen();
213};
214
215/// ForExprAST - Expression class for for/in.
216class ForExprAST : public ExprAST {
217  std::string VarName;
218  ExprAST *Start, *End, *Step, *Body;
219public:
220  ForExprAST(const std::string &varname, ExprAST *start, ExprAST *end,
221             ExprAST *step, ExprAST *body)
222    : VarName(varname), Start(start), End(end), Step(step), Body(body) {}
223  virtual Value *Codegen();
224};
225
226/// VarExprAST - Expression class for var/in
227class VarExprAST : public ExprAST {
228  std::vector<std::pair<std::string, ExprAST*> > VarNames;
229  ExprAST *Body;
230public:
231  VarExprAST(const std::vector<std::pair<std::string, ExprAST*> > &varnames,
232             ExprAST *body)
233  : VarNames(varnames), Body(body) {}
234
235  virtual Value *Codegen();
236};
237
238/// PrototypeAST - This class represents the "prototype" for a function,
239/// which captures its argument names as well as if it is an operator.
240class PrototypeAST {
241  std::string Name;
242  std::vector<std::string> Args;
243  bool isOperator;
244  unsigned Precedence;  // Precedence if a binary op.
245public:
246  PrototypeAST(const std::string &name, const std::vector<std::string> &args,
247               bool isoperator = false, unsigned prec = 0)
248  : Name(name), Args(args), isOperator(isoperator), Precedence(prec) {}
249
250  bool isUnaryOp() const { return isOperator && Args.size() == 1; }
251  bool isBinaryOp() const { return isOperator && Args.size() == 2; }
252
253  char getOperatorName() const {
254    assert(isUnaryOp() || isBinaryOp());
255    return Name[Name.size()-1];
256  }
257
258  unsigned getBinaryPrecedence() const { return Precedence; }
259
260  Function *Codegen();
261
262  void CreateArgumentAllocas(Function *F);
263};
264
265/// FunctionAST - This class represents a function definition itself.
266class FunctionAST {
267  PrototypeAST *Proto;
268  ExprAST *Body;
269public:
270  FunctionAST(PrototypeAST *proto, ExprAST *body)
271    : Proto(proto), Body(body) {}
272
273  Function *Codegen();
274};
275
276//===----------------------------------------------------------------------===//
277// Parser
278//===----------------------------------------------------------------------===//
279
280/// CurTok/getNextToken - Provide a simple token buffer.  CurTok is the current
281/// token the parser is looking at.  getNextToken reads another token from the
282/// lexer and updates CurTok with its results.
283static int CurTok;
284static int getNextToken() {
285  return CurTok = gettok();
286}
287
288/// BinopPrecedence - This holds the precedence for each binary operator that is
289/// defined.
290static std::map<char, int> BinopPrecedence;
291
292/// GetTokPrecedence - Get the precedence of the pending binary operator token.
293static int GetTokPrecedence() {
294  if (!isascii(CurTok))
295    return -1;
296
297  // Make sure it's a declared binop.
298  int TokPrec = BinopPrecedence[CurTok];
299  if (TokPrec <= 0) return -1;
300  return TokPrec;
301}
302
303/// Error* - These are little helper functions for error handling.
304ExprAST *Error(const char *Str) { fprintf(stderr, "Error: %s\n", Str);return 0;}
305PrototypeAST *ErrorP(const char *Str) { Error(Str); return 0; }
306FunctionAST *ErrorF(const char *Str) { Error(Str); return 0; }
307
308static ExprAST *ParseExpression();
309
310/// identifierexpr
311///   ::= identifier
312///   ::= identifier '(' expression* ')'
313static ExprAST *ParseIdentifierExpr() {
314  std::string IdName = IdentifierStr;
315
316  getNextToken();  // eat identifier.
317
318  if (CurTok != '(') // Simple variable ref.
319    return new VariableExprAST(IdName);
320
321  // Call.
322  getNextToken();  // eat (
323  std::vector<ExprAST*> Args;
324  if (CurTok != ')') {
325    while (1) {
326      ExprAST *Arg = ParseExpression();
327      if (!Arg) return 0;
328      Args.push_back(Arg);
329
330      if (CurTok == ')') break;
331
332      if (CurTok != ',')
333        return Error("Expected ')' or ',' in argument list");
334      getNextToken();
335    }
336  }
337
338  // Eat the ')'.
339  getNextToken();
340
341  return new CallExprAST(IdName, Args);
342}
343
344/// numberexpr ::= number
345static ExprAST *ParseNumberExpr() {
346  ExprAST *Result = new NumberExprAST(NumVal);
347  getNextToken(); // consume the number
348  return Result;
349}
350
351/// parenexpr ::= '(' expression ')'
352static ExprAST *ParseParenExpr() {
353  getNextToken();  // eat (.
354  ExprAST *V = ParseExpression();
355  if (!V) return 0;
356
357  if (CurTok != ')')
358    return Error("expected ')'");
359  getNextToken();  // eat ).
360  return V;
361}
362
363/// ifexpr ::= 'if' expression 'then' expression 'else' expression
364static ExprAST *ParseIfExpr() {
365  getNextToken();  // eat the if.
366
367  // condition.
368  ExprAST *Cond = ParseExpression();
369  if (!Cond) return 0;
370
371  if (CurTok != tok_then)
372    return Error("expected then");
373  getNextToken();  // eat the then
374
375  ExprAST *Then = ParseExpression();
376  if (Then == 0) return 0;
377
378  if (CurTok != tok_else)
379    return Error("expected else");
380
381  getNextToken();
382
383  ExprAST *Else = ParseExpression();
384  if (!Else) return 0;
385
386  return new IfExprAST(Cond, Then, Else);
387}
388
389/// forexpr ::= 'for' identifier '=' expr ',' expr (',' expr)? 'in' expression
390static ExprAST *ParseForExpr() {
391  getNextToken();  // eat the for.
392
393  if (CurTok != tok_identifier)
394    return Error("expected identifier after for");
395
396  std::string IdName = IdentifierStr;
397  getNextToken();  // eat identifier.
398
399  if (CurTok != '=')
400    return Error("expected '=' after for");
401  getNextToken();  // eat '='.
402
403
404  ExprAST *Start = ParseExpression();
405  if (Start == 0) return 0;
406  if (CurTok != ',')
407    return Error("expected ',' after for start value");
408  getNextToken();
409
410  ExprAST *End = ParseExpression();
411  if (End == 0) return 0;
412
413  // The step value is optional.
414  ExprAST *Step = 0;
415  if (CurTok == ',') {
416    getNextToken();
417    Step = ParseExpression();
418    if (Step == 0) return 0;
419  }
420
421  if (CurTok != tok_in)
422    return Error("expected 'in' after for");
423  getNextToken();  // eat 'in'.
424
425  ExprAST *Body = ParseExpression();
426  if (Body == 0) return 0;
427
428  return new ForExprAST(IdName, Start, End, Step, Body);
429}
430
431/// varexpr ::= 'var' identifier ('=' expression)?
432//                    (',' identifier ('=' expression)?)* 'in' expression
433static ExprAST *ParseVarExpr() {
434  getNextToken();  // eat the var.
435
436  std::vector<std::pair<std::string, ExprAST*> > VarNames;
437
438  // At least one variable name is required.
439  if (CurTok != tok_identifier)
440    return Error("expected identifier after var");
441
442  while (1) {
443    std::string Name = IdentifierStr;
444    getNextToken();  // eat identifier.
445
446    // Read the optional initializer.
447    ExprAST *Init = 0;
448    if (CurTok == '=') {
449      getNextToken(); // eat the '='.
450
451      Init = ParseExpression();
452      if (Init == 0) return 0;
453    }
454
455    VarNames.push_back(std::make_pair(Name, Init));
456
457    // End of var list, exit loop.
458    if (CurTok != ',') break;
459    getNextToken(); // eat the ','.
460
461    if (CurTok != tok_identifier)
462      return Error("expected identifier list after var");
463  }
464
465  // At this point, we have to have 'in'.
466  if (CurTok != tok_in)
467    return Error("expected 'in' keyword after 'var'");
468  getNextToken();  // eat 'in'.
469
470  ExprAST *Body = ParseExpression();
471  if (Body == 0) return 0;
472
473  return new VarExprAST(VarNames, Body);
474}
475
476/// primary
477///   ::= identifierexpr
478///   ::= numberexpr
479///   ::= parenexpr
480///   ::= ifexpr
481///   ::= forexpr
482///   ::= varexpr
483static ExprAST *ParsePrimary() {
484  switch (CurTok) {
485  default: return Error("unknown token when expecting an expression");
486  case tok_identifier: return ParseIdentifierExpr();
487  case tok_number:     return ParseNumberExpr();
488  case '(':            return ParseParenExpr();
489  case tok_if:         return ParseIfExpr();
490  case tok_for:        return ParseForExpr();
491  case tok_var:        return ParseVarExpr();
492  }
493}
494
495/// unary
496///   ::= primary
497///   ::= '!' unary
498static ExprAST *ParseUnary() {
499  // If the current token is not an operator, it must be a primary expr.
500  if (!isascii(CurTok) || CurTok == '(' || CurTok == ',')
501    return ParsePrimary();
502
503  // If this is a unary operator, read it.
504  int Opc = CurTok;
505  getNextToken();
506  if (ExprAST *Operand = ParseUnary())
507    return new UnaryExprAST(Opc, Operand);
508  return 0;
509}
510
511/// binoprhs
512///   ::= ('+' unary)*
513static ExprAST *ParseBinOpRHS(int ExprPrec, ExprAST *LHS) {
514  // If this is a binop, find its precedence.
515  while (1) {
516    int TokPrec = GetTokPrecedence();
517
518    // If this is a binop that binds at least as tightly as the current binop,
519    // consume it, otherwise we are done.
520    if (TokPrec < ExprPrec)
521      return LHS;
522
523    // Okay, we know this is a binop.
524    int BinOp = CurTok;
525    getNextToken();  // eat binop
526
527    // Parse the unary expression after the binary operator.
528    ExprAST *RHS = ParseUnary();
529    if (!RHS) return 0;
530
531    // If BinOp binds less tightly with RHS than the operator after RHS, let
532    // the pending operator take RHS as its LHS.
533    int NextPrec = GetTokPrecedence();
534    if (TokPrec < NextPrec) {
535      RHS = ParseBinOpRHS(TokPrec+1, RHS);
536      if (RHS == 0) return 0;
537    }
538
539    // Merge LHS/RHS.
540    LHS = new BinaryExprAST(BinOp, LHS, RHS);
541  }
542}
543
544/// expression
545///   ::= unary binoprhs
546///
547static ExprAST *ParseExpression() {
548  ExprAST *LHS = ParseUnary();
549  if (!LHS) return 0;
550
551  return ParseBinOpRHS(0, LHS);
552}
553
554/// prototype
555///   ::= id '(' id* ')'
556///   ::= binary LETTER number? (id, id)
557///   ::= unary LETTER (id)
558static PrototypeAST *ParsePrototype() {
559  std::string FnName;
560
561  unsigned Kind = 0; // 0 = identifier, 1 = unary, 2 = binary.
562  unsigned BinaryPrecedence = 30;
563
564  switch (CurTok) {
565  default:
566    return ErrorP("Expected function name in prototype");
567  case tok_identifier:
568    FnName = IdentifierStr;
569    Kind = 0;
570    getNextToken();
571    break;
572  case tok_unary:
573    getNextToken();
574    if (!isascii(CurTok))
575      return ErrorP("Expected unary operator");
576    FnName = "unary";
577    FnName += (char)CurTok;
578    Kind = 1;
579    getNextToken();
580    break;
581  case tok_binary:
582    getNextToken();
583    if (!isascii(CurTok))
584      return ErrorP("Expected binary operator");
585    FnName = "binary";
586    FnName += (char)CurTok;
587    Kind = 2;
588    getNextToken();
589
590    // Read the precedence if present.
591    if (CurTok == tok_number) {
592      if (NumVal < 1 || NumVal > 100)
593        return ErrorP("Invalid precedecnce: must be 1..100");
594      BinaryPrecedence = (unsigned)NumVal;
595      getNextToken();
596    }
597    break;
598  }
599
600  if (CurTok != '(')
601    return ErrorP("Expected '(' in prototype");
602
603  std::vector<std::string> ArgNames;
604  while (getNextToken() == tok_identifier)
605    ArgNames.push_back(IdentifierStr);
606  if (CurTok != ')')
607    return ErrorP("Expected ')' in prototype");
608
609  // success.
610  getNextToken();  // eat ')'.
611
612  // Verify right number of names for operator.
613  if (Kind && ArgNames.size() != Kind)
614    return ErrorP("Invalid number of operands for operator");
615
616  return new PrototypeAST(FnName, ArgNames, Kind != 0, BinaryPrecedence);
617}
618
619/// definition ::= 'def' prototype expression
620static FunctionAST *ParseDefinition() {
621  getNextToken();  // eat def.
622  PrototypeAST *Proto = ParsePrototype();
623  if (Proto == 0) return 0;
624
625  if (ExprAST *E = ParseExpression())
626    return new FunctionAST(Proto, E);
627  return 0;
628}
629
630/// toplevelexpr ::= expression
631static FunctionAST *ParseTopLevelExpr() {
632  if (ExprAST *E = ParseExpression()) {
633    // Make an anonymous proto.
634    PrototypeAST *Proto = new PrototypeAST("", std::vector<std::string>());
635    return new FunctionAST(Proto, E);
636  }
637  return 0;
638}
639
640/// external ::= 'extern' prototype
641static PrototypeAST *ParseExtern() {
642  getNextToken();  // eat extern.
643  return ParsePrototype();
644}
645
646//===----------------------------------------------------------------------===//
647// Quick and dirty hack
648//===----------------------------------------------------------------------===//
649
650// FIXME: Obviously we can do better than this
651std::string GenerateUniqueName(const char *root)
652{
653  static int i = 0;
654  char s[16];
655  sprintf(s, "%s%d", root, i++);
656  std::string S = s;
657  return S;
658}
659
660std::string MakeLegalFunctionName(std::string Name)
661{
662  std::string NewName;
663  if (!Name.length())
664      return GenerateUniqueName("anon_func_");
665
666  // Start with what we have
667  NewName = Name;
668
669  // Look for a numberic first character
670  if (NewName.find_first_of("0123456789") == 0) {
671    NewName.insert(0, 1, 'n');
672  }
673
674  // Replace illegal characters with their ASCII equivalent
675  std::string legal_elements = "_abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
676  size_t pos;
677  while ((pos = NewName.find_first_not_of(legal_elements)) != std::string::npos) {
678    char old_c = NewName.at(pos);
679    char new_str[16];
680    sprintf(new_str, "%d", (int)old_c);
681    NewName = NewName.replace(pos, 1, new_str);
682  }
683
684  return NewName;
685}
686
687//===----------------------------------------------------------------------===//
688// MCJIT object cache class
689//===----------------------------------------------------------------------===//
690
691class MCJITObjectCache : public ObjectCache {
692public:
693  MCJITObjectCache() {
694    // Set IR cache directory
695    sys::fs::current_path(CacheDir);
696    sys::path::append(CacheDir, "toy_object_cache");
697  }
698
699  virtual ~MCJITObjectCache() {
700  }
701
702  virtual void notifyObjectCompiled(const Module *M, const MemoryBuffer *Obj) {
703    // Get the ModuleID
704    const std::string ModuleID = M->getModuleIdentifier();
705
706    // If we've flagged this as an IR file, cache it
707    if (0 == ModuleID.compare(0, 3, "IR:")) {
708      std::string IRFileName = ModuleID.substr(3);
709      SmallString<128>IRCacheFile = CacheDir;
710      sys::path::append(IRCacheFile, IRFileName);
711      if (!sys::fs::exists(CacheDir.str()) && sys::fs::create_directory(CacheDir.str())) {
712        fprintf(stderr, "Unable to create cache directory\n");
713        return;
714      }
715      std::string ErrStr;
716      raw_fd_ostream IRObjectFile(IRCacheFile.c_str(), ErrStr, raw_fd_ostream::F_Binary);
717      IRObjectFile << Obj->getBuffer();
718    }
719  }
720
721  // MCJIT will call this function before compiling any module
722  // MCJIT takes ownership of both the MemoryBuffer object and the memory
723  // to which it refers.
724  virtual MemoryBuffer* getObject(const Module* M) {
725    // Get the ModuleID
726    const std::string ModuleID = M->getModuleIdentifier();
727
728    // If we've flagged this as an IR file, cache it
729    if (0 == ModuleID.compare(0, 3, "IR:")) {
730      std::string IRFileName = ModuleID.substr(3);
731      SmallString<128> IRCacheFile = CacheDir;
732      sys::path::append(IRCacheFile, IRFileName);
733      if (!sys::fs::exists(IRCacheFile.str())) {
734        // This file isn't in our cache
735        return NULL;
736      }
737      std::unique_ptr<MemoryBuffer> IRObjectBuffer;
738      MemoryBuffer::getFile(IRCacheFile.c_str(), IRObjectBuffer, -1, false);
739      // MCJIT will want to write into this buffer, and we don't want that
740      // because the file has probably just been mmapped.  Instead we make
741      // a copy.  The filed-based buffer will be released when it goes
742      // out of scope.
743      return MemoryBuffer::getMemBufferCopy(IRObjectBuffer->getBuffer());
744    }
745
746    return NULL;
747  }
748
749private:
750  SmallString<128> CacheDir;
751};
752
753//===----------------------------------------------------------------------===//
754// IR input file handler
755//===----------------------------------------------------------------------===//
756
757Module* parseInputIR(std::string InputFile, LLVMContext &Context) {
758  SMDiagnostic Err;
759  Module *M = ParseIRFile(InputFile, Err, Context);
760  if (!M) {
761    Err.print("IR parsing failed: ", errs());
762    return NULL;
763  }
764
765  char ModID[256];
766  sprintf(ModID, "IR:%s", InputFile.c_str());
767  M->setModuleIdentifier(ModID);
768  return M;
769}
770
771//===----------------------------------------------------------------------===//
772// Helper class for execution engine abstraction
773//===----------------------------------------------------------------------===//
774
775class BaseHelper
776{
777public:
778  BaseHelper() {}
779  virtual ~BaseHelper() {}
780
781  virtual Function *getFunction(const std::string FnName) = 0;
782  virtual Module *getModuleForNewFunction() = 0;
783  virtual void *getPointerToFunction(Function* F) = 0;
784  virtual void *getPointerToNamedFunction(const std::string &Name) = 0;
785  virtual void closeCurrentModule() = 0;
786  virtual void runFPM(Function &F) = 0;
787  virtual void dump();
788};
789
790//===----------------------------------------------------------------------===//
791// MCJIT helper class
792//===----------------------------------------------------------------------===//
793
794class MCJITHelper : public BaseHelper
795{
796public:
797  MCJITHelper(LLVMContext& C) : Context(C), CurrentModule(NULL) {
798    if (!InputIR.empty()) {
799      Module *M = parseInputIR(InputIR, Context);
800      Modules.push_back(M);
801      if (!EnableLazyCompilation)
802        compileModule(M);
803    }
804  }
805  ~MCJITHelper();
806
807  Function *getFunction(const std::string FnName);
808  Module *getModuleForNewFunction();
809  void *getPointerToFunction(Function* F);
810  void *getPointerToNamedFunction(const std::string &Name);
811  void closeCurrentModule();
812  virtual void runFPM(Function &F) {} // Not needed, see compileModule
813  void dump();
814
815protected:
816  ExecutionEngine *compileModule(Module *M);
817
818private:
819  typedef std::vector<Module*> ModuleVector;
820
821  MCJITObjectCache OurObjectCache;
822
823  LLVMContext  &Context;
824  ModuleVector  Modules;
825
826  std::map<Module *, ExecutionEngine *> EngineMap;
827
828  Module       *CurrentModule;
829};
830
831class HelpingMemoryManager : public SectionMemoryManager
832{
833  HelpingMemoryManager(const HelpingMemoryManager&) = delete;
834  void operator=(const HelpingMemoryManager&) = delete;
835
836public:
837  HelpingMemoryManager(MCJITHelper *Helper) : MasterHelper(Helper) {}
838  virtual ~HelpingMemoryManager() {}
839
840  /// This method returns the address of the specified function.
841  /// Our implementation will attempt to find functions in other
842  /// modules associated with the MCJITHelper to cross link functions
843  /// from one generated module to another.
844  ///
845  /// If \p AbortOnFailure is false and no function with the given name is
846  /// found, this function returns a null pointer. Otherwise, it prints a
847  /// message to stderr and aborts.
848  virtual void *getPointerToNamedFunction(const std::string &Name,
849                                          bool AbortOnFailure = true);
850private:
851  MCJITHelper *MasterHelper;
852};
853
854void *HelpingMemoryManager::getPointerToNamedFunction(const std::string &Name,
855                                        bool AbortOnFailure)
856{
857  // Try the standard symbol resolution first, but ask it not to abort.
858  void *pfn = RTDyldMemoryManager::getPointerToNamedFunction(Name, false);
859  if (pfn)
860    return pfn;
861
862  pfn = MasterHelper->getPointerToNamedFunction(Name);
863  if (!pfn && AbortOnFailure)
864    report_fatal_error("Program used external function '" + Name +
865                        "' which could not be resolved!");
866  return pfn;
867}
868
869MCJITHelper::~MCJITHelper()
870{
871  // Walk the vector of modules.
872  ModuleVector::iterator it, end;
873  for (it = Modules.begin(), end = Modules.end();
874       it != end; ++it) {
875    // See if we have an execution engine for this module.
876    std::map<Module*, ExecutionEngine*>::iterator mapIt = EngineMap.find(*it);
877    // If we have an EE, the EE owns the module so just delete the EE.
878    if (mapIt != EngineMap.end()) {
879      delete mapIt->second;
880    } else {
881      // Otherwise, we still own the module.  Delete it now.
882      delete *it;
883    }
884  }
885}
886
887Function *MCJITHelper::getFunction(const std::string FnName) {
888  ModuleVector::iterator begin = Modules.begin();
889  ModuleVector::iterator end = Modules.end();
890  ModuleVector::iterator it;
891  for (it = begin; it != end; ++it) {
892    Function *F = (*it)->getFunction(FnName);
893    if (F) {
894      if (*it == CurrentModule)
895          return F;
896
897      assert(CurrentModule != NULL);
898
899      // This function is in a module that has already been JITed.
900      // We just need a prototype for external linkage.
901      Function *PF = CurrentModule->getFunction(FnName);
902      if (PF && !PF->empty()) {
903        ErrorF("redefinition of function across modules");
904        return 0;
905      }
906
907      // If we don't have a prototype yet, create one.
908      if (!PF)
909        PF = Function::Create(F->getFunctionType(),
910                                      Function::ExternalLinkage,
911                                      FnName,
912                                      CurrentModule);
913      return PF;
914    }
915  }
916  return NULL;
917}
918
919Module *MCJITHelper::getModuleForNewFunction() {
920  // If we have a Module that hasn't been JITed, use that.
921  if (CurrentModule)
922    return CurrentModule;
923
924  // Otherwise create a new Module.
925  std::string ModName = GenerateUniqueName("mcjit_module_");
926  Module *M = new Module(ModName, Context);
927  Modules.push_back(M);
928  CurrentModule = M;
929
930  return M;
931}
932
933ExecutionEngine *MCJITHelper::compileModule(Module *M) {
934  assert(EngineMap.find(M) == EngineMap.end());
935
936  if (M == CurrentModule)
937    closeCurrentModule();
938
939  std::string ErrStr;
940  ExecutionEngine *EE = EngineBuilder(M)
941                            .setErrorStr(&ErrStr)
942                            .setMCJITMemoryManager(new HelpingMemoryManager(this))
943                            .create();
944  if (!EE) {
945    fprintf(stderr, "Could not create ExecutionEngine: %s\n", ErrStr.c_str());
946    exit(1);
947  }
948
949  if (UseObjectCache)
950    EE->setObjectCache(&OurObjectCache);
951  // Get the ModuleID so we can identify IR input files
952  const std::string ModuleID = M->getModuleIdentifier();
953
954  // If we've flagged this as an IR file, it doesn't need function passes run.
955  if (0 != ModuleID.compare(0, 3, "IR:")) {
956    FunctionPassManager *FPM = 0;
957
958    // Create a FPM for this module
959    FPM = new FunctionPassManager(M);
960
961    // Set up the optimizer pipeline.  Start with registering info about how the
962    // target lays out data structures.
963    FPM->add(new DataLayout(*EE->getDataLayout()));
964    // Provide basic AliasAnalysis support for GVN.
965    FPM->add(createBasicAliasAnalysisPass());
966    // Promote allocas to registers.
967    FPM->add(createPromoteMemoryToRegisterPass());
968    // Do simple "peephole" optimizations and bit-twiddling optzns.
969    FPM->add(createInstructionCombiningPass());
970    // Reassociate expressions.
971    FPM->add(createReassociatePass());
972    // Eliminate Common SubExpressions.
973    FPM->add(createGVNPass());
974    // Simplify the control flow graph (deleting unreachable blocks, etc).
975    FPM->add(createCFGSimplificationPass());
976
977    FPM->doInitialization();
978
979    // For each function in the module
980    Module::iterator it;
981    Module::iterator end = M->end();
982    for (it = M->begin(); it != end; ++it) {
983      // Run the FPM on this function
984      FPM->run(*it);
985    }
986
987    delete FPM;
988  }
989
990  EE->finalizeObject();
991
992  // Store this engine
993  EngineMap[M] = EE;
994
995  return EE;
996}
997
998void *MCJITHelper::getPointerToFunction(Function* F) {
999  // Look for this function in an existing module
1000  ModuleVector::iterator begin = Modules.begin();
1001  ModuleVector::iterator end = Modules.end();
1002  ModuleVector::iterator it;
1003  std::string FnName = F->getName();
1004  for (it = begin; it != end; ++it) {
1005    Function *MF = (*it)->getFunction(FnName);
1006    if (MF == F) {
1007      std::map<Module*, ExecutionEngine*>::iterator eeIt = EngineMap.find(*it);
1008      if (eeIt != EngineMap.end()) {
1009        void *P = eeIt->second->getPointerToFunction(F);
1010        if (P)
1011          return P;
1012      } else {
1013        ExecutionEngine *EE = compileModule(*it);
1014        void *P = EE->getPointerToFunction(F);
1015        if (P)
1016          return P;
1017      }
1018    }
1019  }
1020  return NULL;
1021}
1022
1023void MCJITHelper::closeCurrentModule() {
1024    // If we have an open module (and we should), pack it up
1025  if (CurrentModule) {
1026    CurrentModule = NULL;
1027  }
1028}
1029
1030void *MCJITHelper::getPointerToNamedFunction(const std::string &Name)
1031{
1032  // Look for the functions in our modules, compiling only as necessary
1033  ModuleVector::iterator begin = Modules.begin();
1034  ModuleVector::iterator end = Modules.end();
1035  ModuleVector::iterator it;
1036  for (it = begin; it != end; ++it) {
1037    Function *F = (*it)->getFunction(Name);
1038    if (F && !F->empty()) {
1039      std::map<Module*, ExecutionEngine*>::iterator eeIt = EngineMap.find(*it);
1040      if (eeIt != EngineMap.end()) {
1041        void *P = eeIt->second->getPointerToFunction(F);
1042        if (P)
1043          return P;
1044      } else {
1045        ExecutionEngine *EE = compileModule(*it);
1046        void *P = EE->getPointerToFunction(F);
1047        if (P)
1048          return P;
1049      }
1050    }
1051  }
1052  return NULL;
1053}
1054
1055void MCJITHelper::dump()
1056{
1057  ModuleVector::iterator begin = Modules.begin();
1058  ModuleVector::iterator end = Modules.end();
1059  ModuleVector::iterator it;
1060  for (it = begin; it != end; ++it)
1061    (*it)->dump();
1062}
1063
1064//===----------------------------------------------------------------------===//
1065// Code Generation
1066//===----------------------------------------------------------------------===//
1067
1068static BaseHelper *TheHelper;
1069static IRBuilder<> Builder(getGlobalContext());
1070static std::map<std::string, AllocaInst*> NamedValues;
1071
1072Value *ErrorV(const char *Str) { Error(Str); return 0; }
1073
1074/// CreateEntryBlockAlloca - Create an alloca instruction in the entry block of
1075/// the function.  This is used for mutable variables etc.
1076static AllocaInst *CreateEntryBlockAlloca(Function *TheFunction,
1077                                          const std::string &VarName) {
1078  IRBuilder<> TmpB(&TheFunction->getEntryBlock(),
1079                 TheFunction->getEntryBlock().begin());
1080  return TmpB.CreateAlloca(Type::getDoubleTy(getGlobalContext()), 0,
1081                           VarName.c_str());
1082}
1083
1084Value *NumberExprAST::Codegen() {
1085  return ConstantFP::get(getGlobalContext(), APFloat(Val));
1086}
1087
1088Value *VariableExprAST::Codegen() {
1089  // Look this variable up in the function.
1090  Value *V = NamedValues[Name];
1091  if (V == 0) return ErrorV("Unknown variable name");
1092
1093  // Load the value.
1094  return Builder.CreateLoad(V, Name.c_str());
1095}
1096
1097Value *UnaryExprAST::Codegen() {
1098  Value *OperandV = Operand->Codegen();
1099  if (OperandV == 0) return 0;
1100  Function *F;
1101  F = TheHelper->getFunction(
1102      MakeLegalFunctionName(std::string("unary") + Opcode));
1103  if (F == 0)
1104    return ErrorV("Unknown unary operator");
1105
1106  return Builder.CreateCall(F, OperandV, "unop");
1107}
1108
1109Value *BinaryExprAST::Codegen() {
1110  // Special case '=' because we don't want to emit the LHS as an expression.
1111  if (Op == '=') {
1112    // Assignment requires the LHS to be an identifier.
1113    // This assume we're building without RTTI because LLVM builds that way by
1114    // default.  If you build LLVM with RTTI this can be changed to a
1115    // dynamic_cast for automatic error checking.
1116    VariableExprAST *LHSE = static_cast<VariableExprAST*>(LHS);
1117    if (!LHSE)
1118      return ErrorV("destination of '=' must be a variable");
1119    // Codegen the RHS.
1120    Value *Val = RHS->Codegen();
1121    if (Val == 0) return 0;
1122
1123    // Look up the name.
1124    Value *Variable = NamedValues[LHSE->getName()];
1125    if (Variable == 0) return ErrorV("Unknown variable name");
1126
1127    Builder.CreateStore(Val, Variable);
1128    return Val;
1129  }
1130
1131  Value *L = LHS->Codegen();
1132  Value *R = RHS->Codegen();
1133  if (L == 0 || R == 0) return 0;
1134
1135  switch (Op) {
1136  case '+': return Builder.CreateFAdd(L, R, "addtmp");
1137  case '-': return Builder.CreateFSub(L, R, "subtmp");
1138  case '*': return Builder.CreateFMul(L, R, "multmp");
1139  case '/': return Builder.CreateFDiv(L, R, "divtmp");
1140  case '<':
1141    L = Builder.CreateFCmpULT(L, R, "cmptmp");
1142    // Convert bool 0/1 to double 0.0 or 1.0
1143    return Builder.CreateUIToFP(L, Type::getDoubleTy(getGlobalContext()),
1144                                "booltmp");
1145  default: break;
1146  }
1147
1148  // If it wasn't a builtin binary operator, it must be a user defined one. Emit
1149  // a call to it.
1150  Function *F;
1151  F = TheHelper->getFunction(MakeLegalFunctionName(std::string("binary")+Op));
1152  assert(F && "binary operator not found!");
1153
1154  Value *Ops[] = { L, R };
1155  return Builder.CreateCall(F, Ops, "binop");
1156}
1157
1158Value *CallExprAST::Codegen() {
1159  // Look up the name in the global module table.
1160  Function *CalleeF = TheHelper->getFunction(Callee);
1161  if (CalleeF == 0) {
1162    char error_str[64];
1163    sprintf(error_str, "Unknown function referenced %s", Callee.c_str());
1164    return ErrorV(error_str);
1165  }
1166
1167  // If argument mismatch error.
1168  if (CalleeF->arg_size() != Args.size())
1169    return ErrorV("Incorrect # arguments passed");
1170
1171  std::vector<Value*> ArgsV;
1172  for (unsigned i = 0, e = Args.size(); i != e; ++i) {
1173    ArgsV.push_back(Args[i]->Codegen());
1174    if (ArgsV.back() == 0) return 0;
1175  }
1176
1177  return Builder.CreateCall(CalleeF, ArgsV, "calltmp");
1178}
1179
1180Value *IfExprAST::Codegen() {
1181  Value *CondV = Cond->Codegen();
1182  if (CondV == 0) return 0;
1183
1184  // Convert condition to a bool by comparing equal to 0.0.
1185  CondV = Builder.CreateFCmpONE(CondV,
1186                              ConstantFP::get(getGlobalContext(), APFloat(0.0)),
1187                                "ifcond");
1188
1189  Function *TheFunction = Builder.GetInsertBlock()->getParent();
1190
1191  // Create blocks for the then and else cases.  Insert the 'then' block at the
1192  // end of the function.
1193  BasicBlock *ThenBB = BasicBlock::Create(getGlobalContext(), "then", TheFunction);
1194  BasicBlock *ElseBB = BasicBlock::Create(getGlobalContext(), "else");
1195  BasicBlock *MergeBB = BasicBlock::Create(getGlobalContext(), "ifcont");
1196
1197  Builder.CreateCondBr(CondV, ThenBB, ElseBB);
1198
1199  // Emit then value.
1200  Builder.SetInsertPoint(ThenBB);
1201
1202  Value *ThenV = Then->Codegen();
1203  if (ThenV == 0) return 0;
1204
1205  Builder.CreateBr(MergeBB);
1206  // Codegen of 'Then' can change the current block, update ThenBB for the PHI.
1207  ThenBB = Builder.GetInsertBlock();
1208
1209  // Emit else block.
1210  TheFunction->getBasicBlockList().push_back(ElseBB);
1211  Builder.SetInsertPoint(ElseBB);
1212
1213  Value *ElseV = Else->Codegen();
1214  if (ElseV == 0) return 0;
1215
1216  Builder.CreateBr(MergeBB);
1217  // Codegen of 'Else' can change the current block, update ElseBB for the PHI.
1218  ElseBB = Builder.GetInsertBlock();
1219
1220  // Emit merge block.
1221  TheFunction->getBasicBlockList().push_back(MergeBB);
1222  Builder.SetInsertPoint(MergeBB);
1223  PHINode *PN = Builder.CreatePHI(Type::getDoubleTy(getGlobalContext()), 2,
1224                                  "iftmp");
1225
1226  PN->addIncoming(ThenV, ThenBB);
1227  PN->addIncoming(ElseV, ElseBB);
1228  return PN;
1229}
1230
1231Value *ForExprAST::Codegen() {
1232  // Output this as:
1233  //   var = alloca double
1234  //   ...
1235  //   start = startexpr
1236  //   store start -> var
1237  //   goto loop
1238  // loop:
1239  //   ...
1240  //   bodyexpr
1241  //   ...
1242  // loopend:
1243  //   step = stepexpr
1244  //   endcond = endexpr
1245  //
1246  //   curvar = load var
1247  //   nextvar = curvar + step
1248  //   store nextvar -> var
1249  //   br endcond, loop, endloop
1250  // outloop:
1251
1252  Function *TheFunction = Builder.GetInsertBlock()->getParent();
1253
1254  // Create an alloca for the variable in the entry block.
1255  AllocaInst *Alloca = CreateEntryBlockAlloca(TheFunction, VarName);
1256
1257  // Emit the start code first, without 'variable' in scope.
1258  Value *StartVal = Start->Codegen();
1259  if (StartVal == 0) return 0;
1260
1261  // Store the value into the alloca.
1262  Builder.CreateStore(StartVal, Alloca);
1263
1264  // Make the new basic block for the loop header, inserting after current
1265  // block.
1266  BasicBlock *LoopBB = BasicBlock::Create(getGlobalContext(), "loop", TheFunction);
1267
1268  // Insert an explicit fall through from the current block to the LoopBB.
1269  Builder.CreateBr(LoopBB);
1270
1271  // Start insertion in LoopBB.
1272  Builder.SetInsertPoint(LoopBB);
1273
1274  // Within the loop, the variable is defined equal to the PHI node.  If it
1275  // shadows an existing variable, we have to restore it, so save it now.
1276  AllocaInst *OldVal = NamedValues[VarName];
1277  NamedValues[VarName] = Alloca;
1278
1279  // Emit the body of the loop.  This, like any other expr, can change the
1280  // current BB.  Note that we ignore the value computed by the body, but don't
1281  // allow an error.
1282  if (Body->Codegen() == 0)
1283    return 0;
1284
1285  // Emit the step value.
1286  Value *StepVal;
1287  if (Step) {
1288    StepVal = Step->Codegen();
1289    if (StepVal == 0) return 0;
1290  } else {
1291    // If not specified, use 1.0.
1292    StepVal = ConstantFP::get(getGlobalContext(), APFloat(1.0));
1293  }
1294
1295  // Compute the end condition.
1296  Value *EndCond = End->Codegen();
1297  if (EndCond == 0) return EndCond;
1298
1299  // Reload, increment, and restore the alloca.  This handles the case where
1300  // the body of the loop mutates the variable.
1301  Value *CurVar = Builder.CreateLoad(Alloca, VarName.c_str());
1302  Value *NextVar = Builder.CreateFAdd(CurVar, StepVal, "nextvar");
1303  Builder.CreateStore(NextVar, Alloca);
1304
1305  // Convert condition to a bool by comparing equal to 0.0.
1306  EndCond = Builder.CreateFCmpONE(EndCond,
1307                              ConstantFP::get(getGlobalContext(), APFloat(0.0)),
1308                                  "loopcond");
1309
1310  // Create the "after loop" block and insert it.
1311  BasicBlock *AfterBB = BasicBlock::Create(getGlobalContext(), "afterloop", TheFunction);
1312
1313  // Insert the conditional branch into the end of LoopEndBB.
1314  Builder.CreateCondBr(EndCond, LoopBB, AfterBB);
1315
1316  // Any new code will be inserted in AfterBB.
1317  Builder.SetInsertPoint(AfterBB);
1318
1319  // Restore the unshadowed variable.
1320  if (OldVal)
1321    NamedValues[VarName] = OldVal;
1322  else
1323    NamedValues.erase(VarName);
1324
1325
1326  // for expr always returns 0.0.
1327  return Constant::getNullValue(Type::getDoubleTy(getGlobalContext()));
1328}
1329
1330Value *VarExprAST::Codegen() {
1331  std::vector<AllocaInst *> OldBindings;
1332
1333  Function *TheFunction = Builder.GetInsertBlock()->getParent();
1334
1335  // Register all variables and emit their initializer.
1336  for (unsigned i = 0, e = VarNames.size(); i != e; ++i) {
1337    const std::string &VarName = VarNames[i].first;
1338    ExprAST *Init = VarNames[i].second;
1339
1340    // Emit the initializer before adding the variable to scope, this prevents
1341    // the initializer from referencing the variable itself, and permits stuff
1342    // like this:
1343    //  var a = 1 in
1344    //    var a = a in ...   # refers to outer 'a'.
1345    Value *InitVal;
1346    if (Init) {
1347      InitVal = Init->Codegen();
1348      if (InitVal == 0) return 0;
1349    } else { // If not specified, use 0.0.
1350      InitVal = ConstantFP::get(getGlobalContext(), APFloat(0.0));
1351    }
1352
1353    AllocaInst *Alloca = CreateEntryBlockAlloca(TheFunction, VarName);
1354    Builder.CreateStore(InitVal, Alloca);
1355
1356    // Remember the old variable binding so that we can restore the binding when
1357    // we unrecurse.
1358    OldBindings.push_back(NamedValues[VarName]);
1359
1360    // Remember this binding.
1361    NamedValues[VarName] = Alloca;
1362  }
1363
1364  // Codegen the body, now that all vars are in scope.
1365  Value *BodyVal = Body->Codegen();
1366  if (BodyVal == 0) return 0;
1367
1368  // Pop all our variables from scope.
1369  for (unsigned i = 0, e = VarNames.size(); i != e; ++i)
1370    NamedValues[VarNames[i].first] = OldBindings[i];
1371
1372  // Return the body computation.
1373  return BodyVal;
1374}
1375
1376Function *PrototypeAST::Codegen() {
1377  // Make the function type:  double(double,double) etc.
1378  std::vector<Type*> Doubles(Args.size(),
1379                             Type::getDoubleTy(getGlobalContext()));
1380  FunctionType *FT = FunctionType::get(Type::getDoubleTy(getGlobalContext()),
1381                                       Doubles, false);
1382
1383  std::string FnName;
1384  FnName = MakeLegalFunctionName(Name);
1385
1386  Module* M = TheHelper->getModuleForNewFunction();
1387  Function *F = Function::Create(FT, Function::ExternalLinkage, FnName, M);
1388
1389  // FIXME: Implement duplicate function detection.
1390  // The check below will only work if the duplicate is in the open module.
1391  // If F conflicted, there was already something named 'Name'.  If it has a
1392  // body, don't allow redefinition or reextern.
1393  if (F->getName() != FnName) {
1394    // Delete the one we just made and get the existing one.
1395    F->eraseFromParent();
1396    F = M->getFunction(FnName);
1397    // If F already has a body, reject this.
1398    if (!F->empty()) {
1399      ErrorF("redefinition of function");
1400      return 0;
1401    }
1402    // If F took a different number of args, reject.
1403    if (F->arg_size() != Args.size()) {
1404      ErrorF("redefinition of function with different # args");
1405      return 0;
1406    }
1407  }
1408
1409  // Set names for all arguments.
1410  unsigned Idx = 0;
1411  for (Function::arg_iterator AI = F->arg_begin(); Idx != Args.size();
1412       ++AI, ++Idx)
1413    AI->setName(Args[Idx]);
1414
1415  return F;
1416}
1417
1418/// CreateArgumentAllocas - Create an alloca for each argument and register the
1419/// argument in the symbol table so that references to it will succeed.
1420void PrototypeAST::CreateArgumentAllocas(Function *F) {
1421  Function::arg_iterator AI = F->arg_begin();
1422  for (unsigned Idx = 0, e = Args.size(); Idx != e; ++Idx, ++AI) {
1423    // Create an alloca for this variable.
1424    AllocaInst *Alloca = CreateEntryBlockAlloca(F, Args[Idx]);
1425
1426    // Store the initial value into the alloca.
1427    Builder.CreateStore(AI, Alloca);
1428
1429    // Add arguments to variable symbol table.
1430    NamedValues[Args[Idx]] = Alloca;
1431  }
1432}
1433
1434Function *FunctionAST::Codegen() {
1435  NamedValues.clear();
1436
1437  Function *TheFunction = Proto->Codegen();
1438  if (TheFunction == 0)
1439    return 0;
1440
1441  // If this is an operator, install it.
1442  if (Proto->isBinaryOp())
1443    BinopPrecedence[Proto->getOperatorName()] = Proto->getBinaryPrecedence();
1444
1445  // Create a new basic block to start insertion into.
1446  BasicBlock *BB = BasicBlock::Create(getGlobalContext(), "entry", TheFunction);
1447  Builder.SetInsertPoint(BB);
1448
1449  // Add all arguments to the symbol table and create their allocas.
1450  Proto->CreateArgumentAllocas(TheFunction);
1451
1452  if (Value *RetVal = Body->Codegen()) {
1453    // Finish off the function.
1454    Builder.CreateRet(RetVal);
1455
1456    // Validate the generated code, checking for consistency.
1457    verifyFunction(*TheFunction);
1458
1459    return TheFunction;
1460  }
1461
1462  // Error reading body, remove function.
1463  TheFunction->eraseFromParent();
1464
1465  if (Proto->isBinaryOp())
1466    BinopPrecedence.erase(Proto->getOperatorName());
1467  return 0;
1468}
1469
1470//===----------------------------------------------------------------------===//
1471// Top-Level parsing and JIT Driver
1472//===----------------------------------------------------------------------===//
1473
1474static void HandleDefinition() {
1475  if (FunctionAST *F = ParseDefinition()) {
1476    if (EnableLazyCompilation)
1477      TheHelper->closeCurrentModule();
1478    Function *LF = F->Codegen();
1479    if (LF && VerboseOutput) {
1480      fprintf(stderr, "Read function definition:");
1481      LF->dump();
1482    }
1483  } else {
1484    // Skip token for error recovery.
1485    getNextToken();
1486  }
1487}
1488
1489static void HandleExtern() {
1490  if (PrototypeAST *P = ParseExtern()) {
1491    Function *F = P->Codegen();
1492    if (F && VerboseOutput) {
1493      fprintf(stderr, "Read extern: ");
1494      F->dump();
1495    }
1496  } else {
1497    // Skip token for error recovery.
1498    getNextToken();
1499  }
1500}
1501
1502static void HandleTopLevelExpression() {
1503  // Evaluate a top-level expression into an anonymous function.
1504  if (FunctionAST *F = ParseTopLevelExpr()) {
1505    if (Function *LF = F->Codegen()) {
1506      // JIT the function, returning a function pointer.
1507      void *FPtr = TheHelper->getPointerToFunction(LF);
1508      // Cast it to the right type (takes no arguments, returns a double) so we
1509      // can call it as a native function.
1510      double (*FP)() = (double (*)())(intptr_t)FPtr;
1511      double Result = FP();
1512      if (VerboseOutput)
1513        fprintf(stderr, "Evaluated to %f\n", Result);
1514    }
1515  } else {
1516    // Skip token for error recovery.
1517    getNextToken();
1518  }
1519}
1520
1521/// top ::= definition | external | expression | ';'
1522static void MainLoop() {
1523  while (1) {
1524    if (!SuppressPrompts)
1525      fprintf(stderr, "ready> ");
1526    switch (CurTok) {
1527    case tok_eof:    return;
1528    case ';':        getNextToken(); break;  // ignore top-level semicolons.
1529    case tok_def:    HandleDefinition(); break;
1530    case tok_extern: HandleExtern(); break;
1531    default:         HandleTopLevelExpression(); break;
1532    }
1533  }
1534}
1535
1536//===----------------------------------------------------------------------===//
1537// "Library" functions that can be "extern'd" from user code.
1538//===----------------------------------------------------------------------===//
1539
1540/// putchard - putchar that takes a double and returns 0.
1541extern "C"
1542double putchard(double X) {
1543  putchar((char)X);
1544  return 0;
1545}
1546
1547/// printd - printf that takes a double prints it as "%f\n", returning 0.
1548extern "C"
1549double printd(double X) {
1550  printf("%f", X);
1551  return 0;
1552}
1553
1554extern "C"
1555double printlf() {
1556  printf("\n");
1557  return 0;
1558}
1559
1560//===----------------------------------------------------------------------===//
1561// Main driver code.
1562//===----------------------------------------------------------------------===//
1563
1564int main(int argc, char **argv) {
1565  InitializeNativeTarget();
1566  InitializeNativeTargetAsmPrinter();
1567  InitializeNativeTargetAsmParser();
1568  LLVMContext &Context = getGlobalContext();
1569
1570  cl::ParseCommandLineOptions(argc, argv,
1571                              "Kaleidoscope example program\n");
1572
1573  // Install standard binary operators.
1574  // 1 is lowest precedence.
1575  BinopPrecedence['='] = 2;
1576  BinopPrecedence['<'] = 10;
1577  BinopPrecedence['+'] = 20;
1578  BinopPrecedence['-'] = 20;
1579  BinopPrecedence['/'] = 40;
1580  BinopPrecedence['*'] = 40;  // highest.
1581
1582  // Make the Helper, which holds all the code.
1583  TheHelper = new MCJITHelper(Context);
1584
1585  // Prime the first token.
1586  if (!SuppressPrompts)
1587    fprintf(stderr, "ready> ");
1588  getNextToken();
1589
1590  // Run the main "interpreter loop" now.
1591  MainLoop();
1592
1593  // Print out all of the generated code.
1594  if (DumpModulesOnExit)
1595    TheHelper->dump();
1596
1597  return 0;
1598}
1599