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/Bitcode/ReaderWriter.h"
29 #include "llvm/ExecutionEngine/ExecutionEngine.h"
30 #include "llvm/ExecutionEngine/GenericValue.h"
31 #include "llvm/IR/Constants.h"
32 #include "llvm/IR/Verifier.h"
33 #include "llvm/Support/CommandLine.h"
34 #include "llvm/Support/FileSystem.h"
35 #include "llvm/Support/ManagedStatic.h"
36 #include "llvm/Support/TargetSelect.h"
37 #include "llvm/Support/raw_ostream.h"
38 #include <fstream>
39 #include <iostream>
40 using namespace llvm;
41
42 //Command line options
43
44 static cl::opt<std::string>
45 InputFilename(cl::Positional, cl::desc("<input brainf>"));
46
47 static cl::opt<std::string>
48 OutputFilename("o", cl::desc("Output filename"), cl::value_desc("filename"));
49
50 static cl::opt<bool>
51 ArrayBoundsChecking("abc", cl::desc("Enable array bounds checking"));
52
53 static cl::opt<bool>
54 JIT("jit", cl::desc("Run program Just-In-Time"));
55
56
57 //Add main function so can be fully compiled
addMainFunction(Module * mod)58 void addMainFunction(Module *mod) {
59 //define i32 @main(i32 %argc, i8 **%argv)
60 Function *main_func = cast<Function>(mod->
61 getOrInsertFunction("main", IntegerType::getInt32Ty(mod->getContext()),
62 IntegerType::getInt32Ty(mod->getContext()),
63 PointerType::getUnqual(PointerType::getUnqual(
64 IntegerType::getInt8Ty(mod->getContext()))), NULL));
65 {
66 Function::arg_iterator args = main_func->arg_begin();
67 Value *arg_0 = &*args++;
68 arg_0->setName("argc");
69 Value *arg_1 = &*args++;
70 arg_1->setName("argv");
71 }
72
73 //main.0:
74 BasicBlock *bb = BasicBlock::Create(mod->getContext(), "main.0", main_func);
75
76 //call void @brainf()
77 {
78 CallInst *brainf_call = CallInst::Create(mod->getFunction("brainf"),
79 "", bb);
80 brainf_call->setTailCall(false);
81 }
82
83 //ret i32 0
84 ReturnInst::Create(mod->getContext(),
85 ConstantInt::get(mod->getContext(), APInt(32, 0)), bb);
86 }
87
main(int argc,char ** argv)88 int main(int argc, char **argv) {
89 cl::ParseCommandLineOptions(argc, argv, " BrainF compiler\n");
90
91 LLVMContext &Context = getGlobalContext();
92
93 if (InputFilename == "") {
94 errs() << "Error: You must specify the filename of the program to "
95 "be compiled. Use --help to see the options.\n";
96 abort();
97 }
98
99 //Get the output stream
100 raw_ostream *out = &outs();
101 if (!JIT) {
102 if (OutputFilename == "") {
103 std::string base = InputFilename;
104 if (InputFilename == "-") { base = "a"; }
105
106 // Use default filename.
107 OutputFilename = base+".bc";
108 }
109 if (OutputFilename != "-") {
110 std::error_code EC;
111 out = new raw_fd_ostream(OutputFilename, EC, sys::fs::F_None);
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 std::unique_ptr<Module> Mod(bf.parse(in, 65536, cf, Context)); // 64 KiB
128 if (in != &std::cin)
129 delete in;
130 addMainFunction(Mod.get());
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 Module &M = *Mod;
144 ExecutionEngine *ee = EngineBuilder(std::move(Mod)).create();
145 std::vector<GenericValue> args;
146 Function *brainf_func = M.getFunction("brainf");
147 GenericValue gv = ee->runFunction(brainf_func, args);
148 } else {
149 WriteBitcodeToFile(Mod.get(), *out);
150 }
151
152 //Clean up
153 if (out != &outs())
154 delete out;
155
156 llvm_shutdown();
157
158 return 0;
159 }
160