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
56 using namespace llvm;
57
58 //Command line options
59
60 static cl::opt<std::string>
61 InputFilename(cl::Positional, cl::desc("<input brainf>"));
62
63 static cl::opt<std::string>
64 OutputFilename("o", cl::desc("Output filename"), cl::value_desc("filename"));
65
66 static cl::opt<bool>
67 ArrayBoundsChecking("abc", cl::desc("Enable array bounds checking"));
68
69 static cl::opt<bool>
70 JIT("jit", cl::desc("Run program Just-In-Time"));
71
72 //Add main function so can be fully compiled
addMainFunction(Module * mod)73 void 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
main(int argc,char ** argv)103 int 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