BrainFDriver.cpp revision 8b477ed579794ba6d76915d56b3f448a7dd20120 
1//===-- BrainFDriver.cpp - BrainF compiler driver -----------------------===//
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 program converts the BrainF language into LLVM assembly,
11// which it can then run using the JIT or output as BitCode.
12//
13// This implementation has a tape of 65536 bytes,
14// with the head starting in the middle.
15// Range checking is off by default, so be careful.
16// It can be enabled with -abc.
17//
18// Use:
19// ./BrainF -jit      prog.bf          #Run program now
20// ./BrainF -jit -abc prog.bf          #Run program now safely
21// ./BrainF           prog.bf          #Write as BitCode
22//
23// lli prog.bf.bc                      #Run generated BitCode
24// llvm-ld -native -o=prog prog.bf.bc  #Compile BitCode into native executable
25//
26//===--------------------------------------------------------------------===//
27
28#include "BrainF.h"
29#include "llvm/Constants.h"
30#include "llvm/ModuleProvider.h"
31#include "llvm/Analysis/Verifier.h"
32#include "llvm/Bitcode/ReaderWriter.h"
33#include "llvm/ExecutionEngine/GenericValue.h"
34#include "llvm/ExecutionEngine/JIT.h"
35#include "llvm/Support/CommandLine.h"
36#include "llvm/Support/ManagedStatic.h"
37#include "llvm/Target/TargetSelect.h"
38#include <fstream>
39#include <iostream>
40using namespace llvm;
41
42//Command line options
43
44static cl::opt<std::string>
45InputFilename(cl::Positional, cl::desc("<input brainf>"));
46
47static cl::opt<std::string>
48OutputFilename("o", cl::desc("Output filename"), cl::value_desc("filename"));
49
50static cl::opt<bool>
51ArrayBoundsChecking("abc", cl::desc("Enable array bounds checking"));
52
53static cl::opt<bool>
54JIT("jit", cl::desc("Run program Just-In-Time"));
55
56
57//Add main function so can be fully compiled
58void addMainFunction(Module *mod) {
59  //define i32 @main(i32 %argc, i8 **%argv)
60  Function *main_func = cast<Function>(mod->
61    getOrInsertFunction("main", IntegerType::Int32Ty, IntegerType::Int32Ty,
62                        PointerType::getUnqual(PointerType::getUnqual(
63                          IntegerType::Int8Ty)), NULL));
64  {
65    Function::arg_iterator args = main_func->arg_begin();
66    Value *arg_0 = args++;
67    arg_0->setName("argc");
68    Value *arg_1 = args++;
69    arg_1->setName("argv");
70  }
71
72  //main.0:
73  BasicBlock *bb = BasicBlock::Create("main.0", main_func);
74
75  //call void @brainf()
76  {
77    CallInst *brainf_call = CallInst::Create(mod->getFunction("brainf"),
78                                             "", bb);
79    brainf_call->setTailCall(false);
80  }
81
82  //ret i32 0
83  ReturnInst::Create(ConstantInt::get(APInt(32, 0)), bb);
84}
85
86int main(int argc, char **argv) {
87  cl::ParseCommandLineOptions(argc, argv, " BrainF compiler\n");
88
89  LLVMContext Context;
90
91  if (InputFilename == "") {
92    std::cerr<<"Error: You must specify the filename of the program to "
93    "be compiled.  Use --help to see the options.\n";
94    abort();
95  }
96
97  //Get the output stream
98  std::ostream *out = &std::cout;
99  if (!JIT) {
100    if (OutputFilename == "") {
101      std::string base = InputFilename;
102      if (InputFilename == "-") {base = "a";}
103
104      //Use default filename
105      const char *suffix = ".bc";
106      OutputFilename = base+suffix;
107    }
108    if (OutputFilename != "-") {
109      out = new std::
110        ofstream(OutputFilename.c_str(),
111                 std::ios::out | std::ios::trunc | std::ios::binary);
112    }
113  }
114
115  //Get the input stream
116  std::istream *in = &std::cin;
117  if (InputFilename != "-") {
118    in = new std::ifstream(InputFilename.c_str());
119  }
120
121  //Gather the compile flags
122  BrainF::CompileFlags cf = BrainF::flag_off;
123  if (ArrayBoundsChecking) {
124    cf = BrainF::CompileFlags(cf | BrainF::flag_arraybounds);
125  }
126
127  //Read the BrainF program
128  BrainF bf;
129  Module *mod = bf.parse(in, 65536, cf, &Context); //64 KiB
130  if (in != &std::cin) {delete in;}
131  addMainFunction(mod);
132
133  //Verify generated code
134  if (verifyModule(*mod)) {
135    std::cerr<<"Error: module failed verification.  This shouldn't happen.\n";
136    abort();
137  }
138
139  //Write it out
140  if (JIT) {
141    InitializeNativeTarget();
142
143    std::cout << "------- Running JIT -------\n";
144    ExistingModuleProvider *mp = new ExistingModuleProvider(mod);
145    ExecutionEngine *ee = ExecutionEngine::create(mp, false);
146    std::vector<GenericValue> args;
147    Function *brainf_func = mod->getFunction("brainf");
148    GenericValue gv = ee->runFunction(brainf_func, args);
149  } else {
150    WriteBitcodeToFile(mod, *out);
151  }
152
153  //Clean up
154  if (out != &std::cout) {delete out;}
155  delete mod;
156
157  llvm_shutdown();
158
159  return 0;
160}
161