examples/BrainF/BrainF.h

   1 //===-- BrainF.h - BrainF compiler class ------------------------*- C++ -*-===//
   2 //
   3 //                     The LLVM Compiler Infrastructure
   4 //
   5 // This file is distributed under the University of Illinois Open Source
   6 // License. See LICENSE.TXT for details.
   7 //
   8 //===----------------------------------------------------------------------===//
   9 //
  10 // This class stores the data for the BrainF compiler so it doesn't have
  11 // to pass all of it around.  The main method is parse.
  12 //
  13 //===----------------------------------------------------------------------===//
  14
  15 #ifndef BRAINF_H
  16 #define BRAINF_H
  17
  18 #include "llvm/IR/IRBuilder.h"
  19 #include "llvm/IR/LLVMContext.h"
  20 #include "llvm/IR/Module.h"
  21 #include <istream>
  22
  23 using namespace llvm;
  24
  25 /// This class provides a parser for the BrainF language.
  26 /// The class itself is made to store values during
  27 /// parsing so they don't have to be passed around
  28 /// as much.
  29 class BrainF {
  30   public:
  31     /// Options for how BrainF should compile
  32     enum CompileFlags {
  33       flag_off         = 0,
  34       flag_arraybounds = 1
  35     };
  36
  37     /// This is the main method.  It parses BrainF from in1
  38     /// and returns the module with a function
  39     /// void brainf()
  40     /// containing the resulting code.
  41     /// On error, it calls abort.
  42     /// The caller must delete the returned module.
  43     Module *parse(std::istream *in1, int mem, CompileFlags cf,
  44                   LLVMContext& C);
  45
  46   protected:
  47     /// The different symbols in the BrainF language
  48     enum Symbol {
  49       SYM_NONE,
  50       SYM_READ,
  51       SYM_WRITE,
  52       SYM_MOVE,
  53       SYM_CHANGE,
  54       SYM_LOOP,
  55       SYM_ENDLOOP,
  56       SYM_EOF
  57     };
  58
  59     /// Names of the different parts of the language.
  60     /// Tape is used for reading and writing the tape.
  61     /// headreg is used for the position of the head.
  62     /// label is used for the labels for the BasicBlocks.
  63     /// testreg is used for testing the loop exit condition.
  64     static const char *tapereg;
  65     static const char *headreg;
  66     static const char *label;
  67     static const char *testreg;
  68
  69     /// Put the brainf function preamble and other fixed pieces of code
  70     void header(LLVMContext& C);
  71
  72     /// The main loop for parsing.  It calls itself recursively
  73     /// to handle the depth of nesting of "[]".
  74     void readloop(PHINode *phi, BasicBlock *oldbb,
  75                   BasicBlock *testbb, LLVMContext &Context);
  76
  77     /// Constants during parsing
  78     int memtotal;
  79     CompileFlags comflag;
  80     std::istream *in;
  81     Module *module;
  82     Function *brainf_func;
  83     Function *getchar_func;
  84     Function *putchar_func;
  85     Value *ptr_arr;
  86     Value *ptr_arrmax;
  87     BasicBlock *endbb;
  88     BasicBlock *aberrorbb;
  89
  90     /// Variables
  91     IRBuilder<> *builder;
  92     Value *curhead;
  93 };
  94
  95 #endif // BRAINF_H