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/ADT/APInt.h"
29#include "llvm/Bitcode/ReaderWriter.h"
30#include "llvm/ExecutionEngine/ExecutionEngine.h"
31#include "llvm/ExecutionEngine/GenericValue.h"
32#include "llvm/IR/BasicBlock.h"
33#include "llvm/IR/Constants.h"
34#include "llvm/IR/DerivedTypes.h"
35#include "llvm/IR/Function.h"
36#include "llvm/IR/Instructions.h"
37#include "llvm/IR/LLVMContext.h"
38#include "llvm/IR/Module.h"
39#include "llvm/IR/Value.h"
40#include "llvm/IR/Verifier.h"
41#include "llvm/Support/Casting.h"
42#include "llvm/Support/CommandLine.h"
43#include "llvm/Support/FileSystem.h"
44#include "llvm/Support/ManagedStatic.h"
45#include "llvm/Support/TargetSelect.h"
46#include "llvm/Support/raw_ostream.h"
47#include <algorithm>
48#include <cstdlib>
49#include <fstream>
50#include <iostream>
51#include <memory>
52#include <string>
53#include <system_error>
54#include <vector>
55
56using namespace llvm;
57
58//Command line options
59
60static cl::opt<std::string>
61InputFilename(cl::Positional, cl::desc("<input brainf>"));
62
63static cl::opt<std::string>
64OutputFilename("o", cl::desc("Output filename"), cl::value_desc("filename"));
65
66static cl::opt<bool>
67ArrayBoundsChecking("abc", cl::desc("Enable array bounds checking"));
68
69static cl::opt<bool>
70JIT("jit", cl::desc("Run program Just-In-Time"));
71
72//Add main function so can be fully compiled
73void addMainFunction(Module *mod) {
74  //define i32 @main(i32 %argc, i8 **%argv)
75  Function *main_func = cast<Function>(mod->
76    getOrInsertFunction("main", IntegerType::getInt32Ty(mod->getContext()),
77                        IntegerType::getInt32Ty(mod->getContext()),
78                        PointerType::getUnqual(PointerType::getUnqual(
79                          IntegerType::getInt8Ty(mod->getContext()))), NULL));
80  {
81    Function::arg_iterator args = main_func->arg_begin();
82    Value *arg_0 = &*args++;
83    arg_0->setName("argc");
84    Value *arg_1 = &*args++;
85    arg_1->setName("argv");
86  }
87
88  //main.0:
89  BasicBlock *bb = BasicBlock::Create(mod->getContext(), "main.0", main_func);
90
91  //call void @brainf()
92  {
93    CallInst *brainf_call = CallInst::Create(mod->getFunction("brainf"),
94                                             "", bb);
95    brainf_call->setTailCall(false);
96  }
97
98  //ret i32 0
99  ReturnInst::Create(mod->getContext(),
100                     ConstantInt::get(mod->getContext(), APInt(32, 0)), bb);
101}
102
103int main(int argc, char **argv) {
104  cl::ParseCommandLineOptions(argc, argv, " BrainF compiler\n");
105
106  LLVMContext Context;
107
108  if (InputFilename == "") {
109    errs() << "Error: You must specify the filename of the program to "
110    "be compiled.  Use --help to see the options.\n";
111    abort();
112  }
113
114  //Get the output stream
115  raw_ostream *out = &outs();
116  if (!JIT) {
117    if (OutputFilename == "") {
118      std::string base = InputFilename;
119      if (InputFilename == "-") { base = "a"; }
120
121      // Use default filename.
122      OutputFilename = base+".bc";
123    }
124    if (OutputFilename != "-") {
125      std::error_code EC;
126      out = new raw_fd_ostream(OutputFilename, EC, sys::fs::F_None);
127    }
128  }
129
130  //Get the input stream
131  std::istream *in = &std::cin;
132  if (InputFilename != "-")
133    in = new std::ifstream(InputFilename.c_str());
134
135  //Gather the compile flags
136  BrainF::CompileFlags cf = BrainF::flag_off;
137  if (ArrayBoundsChecking)
138    cf = BrainF::CompileFlags(cf | BrainF::flag_arraybounds);
139
140  //Read the BrainF program
141  BrainF bf;
142  std::unique_ptr<Module> Mod(bf.parse(in, 65536, cf, Context)); // 64 KiB
143  if (in != &std::cin)
144    delete in;
145  addMainFunction(Mod.get());
146
147  //Verify generated code
148  if (verifyModule(*Mod)) {
149    errs() << "Error: module failed verification.  This shouldn't happen.\n";
150    abort();
151  }
152
153  //Write it out
154  if (JIT) {
155    InitializeNativeTarget();
156
157    outs() << "------- Running JIT -------\n";
158    Module &M = *Mod;
159    ExecutionEngine *ee = EngineBuilder(std::move(Mod)).create();
160    std::vector<GenericValue> args;
161    Function *brainf_func = M.getFunction("brainf");
162    GenericValue gv = ee->runFunction(brainf_func, args);
163  } else {
164    WriteBitcodeToFile(Mod.get(), *out);
165  }
166
167  //Clean up
168  if (out != &outs())
169    delete out;
170
171  llvm_shutdown();
172
173  return 0;
174}
175