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//
25//===--------------------------------------------------------------------===//
26
27#include "BrainF.h"
28#include "llvm/Constants.h"
29#include "llvm/Analysis/Verifier.h"
30#include "llvm/Bitcode/ReaderWriter.h"
31#include "llvm/ExecutionEngine/GenericValue.h"
32#include "llvm/ExecutionEngine/JIT.h"
33#include "llvm/Support/CommandLine.h"
34#include "llvm/Support/ManagedStatic.h"
35#include "llvm/Support/TargetSelect.h"
36#include "llvm/Support/raw_ostream.h"
37#include <iostream>
38#include <fstream>
39using namespace llvm;
40
41//Command line options
42
43static cl::opt<std::string>
44InputFilename(cl::Positional, cl::desc("<input brainf>"));
45
46static cl::opt<std::string>
47OutputFilename("o", cl::desc("Output filename"), cl::value_desc("filename"));
48
49static cl::opt<bool>
50ArrayBoundsChecking("abc", cl::desc("Enable array bounds checking"));
51
52static cl::opt<bool>
53JIT("jit", cl::desc("Run program Just-In-Time"));
54
55
56//Add main function so can be fully compiled
57void addMainFunction(Module *mod) {
58  //define i32 @main(i32 %argc, i8 **%argv)
59  Function *main_func = cast<Function>(mod->
60    getOrInsertFunction("main", IntegerType::getInt32Ty(mod->getContext()),
61                        IntegerType::getInt32Ty(mod->getContext()),
62                        PointerType::getUnqual(PointerType::getUnqual(
63                          IntegerType::getInt8Ty(mod->getContext()))), 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(mod->getContext(), "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(mod->getContext(),
84                     ConstantInt::get(mod->getContext(), APInt(32, 0)), bb);
85}
86
87int main(int argc, char **argv) {
88  cl::ParseCommandLineOptions(argc, argv, " BrainF compiler\n");
89
90  LLVMContext &Context = getGlobalContext();
91
92  if (InputFilename == "") {
93    errs() << "Error: You must specify the filename of the program to "
94    "be compiled.  Use --help to see the options.\n";
95    abort();
96  }
97
98  //Get the output stream
99  raw_ostream *out = &outs();
100  if (!JIT) {
101    if (OutputFilename == "") {
102      std::string base = InputFilename;
103      if (InputFilename == "-") { base = "a"; }
104
105      // Use default filename.
106      OutputFilename = base+".bc";
107    }
108    if (OutputFilename != "-") {
109      std::string ErrInfo;
110      out = new raw_fd_ostream(OutputFilename.c_str(), ErrInfo,
111                               raw_fd_ostream::F_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  //Gather the compile flags
121  BrainF::CompileFlags cf = BrainF::flag_off;
122  if (ArrayBoundsChecking)
123    cf = BrainF::CompileFlags(cf | BrainF::flag_arraybounds);
124
125  //Read the BrainF program
126  BrainF bf;
127  Module *mod = bf.parse(in, 65536, cf, Context); //64 KiB
128  if (in != &std::cin)
129    delete in;
130  addMainFunction(mod);
131
132  //Verify generated code
133  if (verifyModule(*mod)) {
134    errs() << "Error: module failed verification.  This shouldn't happen.\n";
135    abort();
136  }
137
138  //Write it out
139  if (JIT) {
140    InitializeNativeTarget();
141
142    outs() << "------- Running JIT -------\n";
143    ExecutionEngine *ee = EngineBuilder(mod).create();
144    std::vector<GenericValue> args;
145    Function *brainf_func = mod->getFunction("brainf");
146    GenericValue gv = ee->runFunction(brainf_func, args);
147  } else {
148    WriteBitcodeToFile(mod, *out);
149  }
150
151  //Clean up
152  if (out != &outs())
153    delete out;
154  delete mod;
155
156  llvm_shutdown();
157
158  return 0;
159}
160