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