BrainF.cpp revision fc001bbfc360ab828e5a4b0cbe4bb7db87361b85
1//===-- BrainF.cpp - BrainF compiler example ----------------------------===// 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 class compiles the BrainF language into LLVM assembly. 11// 12// The BrainF language has 8 commands: 13// Command Equivalent C Action 14// ------- ------------ ------ 15// , *h=getchar(); Read a character from stdin, 255 on EOF 16// . putchar(*h); Write a character to stdout 17// - --*h; Decrement tape 18// + ++*h; Increment tape 19// < --h; Move head left 20// > ++h; Move head right 21// [ while(*h) { Start loop 22// ] } End loop 23// 24//===--------------------------------------------------------------------===// 25 26#include "BrainF.h" 27#include "llvm/Constants.h" 28#include "llvm/ADT/STLExtras.h" 29 30using namespace llvm; 31 32//Set the constants for naming 33const char *BrainF::tapereg = "tape"; 34const char *BrainF::headreg = "head"; 35const char *BrainF::label = "brainf"; 36const char *BrainF::testreg = "test"; 37 38Module *BrainF::parse(std::istream *in1, int mem, CompileFlags cf) { 39 in = in1; 40 memtotal = mem; 41 comflag = cf; 42 43 header(); 44 readloop(0, 0, 0); 45 delete builder; 46 return module; 47} 48 49void BrainF::header() { 50 module = new Module("BrainF"); 51 52 //Function prototypes 53 54 //declare void @llvm.memset.i32(i8 *, i8, i32, i32) 55 Function *memset_func = cast<Function>(module-> 56 getOrInsertFunction("llvm.memset.i32", Type::VoidTy, 57 PointerType::getUnqual(IntegerType::Int8Ty), 58 IntegerType::Int8Ty, IntegerType::Int32Ty, 59 IntegerType::Int32Ty, NULL)); 60 61 //declare i32 @getchar() 62 getchar_func = cast<Function>(module-> 63 getOrInsertFunction("getchar", IntegerType::Int32Ty, NULL)); 64 65 //declare i32 @putchar(i32) 66 putchar_func = cast<Function>(module-> 67 getOrInsertFunction("putchar", IntegerType::Int32Ty, 68 IntegerType::Int32Ty, NULL)); 69 70 71 //Function header 72 73 //define void @brainf() 74 brainf_func = cast<Function>(module-> 75 getOrInsertFunction("brainf", Type::VoidTy, NULL)); 76 77 builder = new LLVMBuilder(new BasicBlock(label, brainf_func)); 78 79 //%arr = malloc i8, i32 %d 80 ConstantInt *val_mem = ConstantInt::get(APInt(32, memtotal)); 81 ptr_arr = builder->CreateMalloc(IntegerType::Int8Ty, val_mem, "arr"); 82 83 //call void @llvm.memset.i32(i8 *%arr, i8 0, i32 %d, i32 1) 84 { 85 Value *memset_params[] = { 86 ptr_arr, 87 ConstantInt::get(APInt(8, 0)), 88 val_mem, 89 ConstantInt::get(APInt(32, 1)) 90 }; 91 92 CallInst *memset_call = builder-> 93 CreateCall(memset_func, memset_params, array_endof(memset_params)); 94 memset_call->setTailCall(false); 95 } 96 97 //%arrmax = getelementptr i8 *%arr, i32 %d 98 if (comflag & flag_arraybounds) { 99 ptr_arrmax = builder-> 100 CreateGEP(ptr_arr, ConstantInt::get(APInt(32, memtotal)), "arrmax"); 101 } 102 103 //%head.%d = getelementptr i8 *%arr, i32 %d 104 curhead = builder->CreateGEP(ptr_arr, 105 ConstantInt::get(APInt(32, memtotal/2)), 106 headreg); 107 108 109 110 //Function footer 111 112 //brainf.end: 113 endbb = new BasicBlock(label, brainf_func); 114 115 //free i8 *%arr 116 new FreeInst(ptr_arr, endbb); 117 118 //ret void 119 new ReturnInst(endbb); 120 121 122 123 //Error block for array out of bounds 124 if (comflag & flag_arraybounds) 125 { 126 //@aberrormsg = internal constant [%d x i8] c"\00" 127 Constant *msg_0 = ConstantArray:: 128 get("Error: The head has left the tape.", true); 129 130 GlobalVariable *aberrormsg = new GlobalVariable( 131 msg_0->getType(), 132 true, 133 GlobalValue::InternalLinkage, 134 msg_0, 135 "aberrormsg", 136 module); 137 138 //declare i32 @puts(i8 *) 139 Function *puts_func = cast<Function>(module-> 140 getOrInsertFunction("puts", IntegerType::Int32Ty, 141 PointerType::getUnqual(IntegerType::Int8Ty), NULL)); 142 143 //brainf.aberror: 144 aberrorbb = new BasicBlock(label, brainf_func); 145 146 //call i32 @puts(i8 *getelementptr([%d x i8] *@aberrormsg, i32 0, i32 0)) 147 { 148 Constant *zero_32 = Constant::getNullValue(IntegerType::Int32Ty); 149 150 Constant *gep_params[] = { 151 zero_32, 152 zero_32 153 }; 154 155 Constant *msgptr = ConstantExpr:: 156 getGetElementPtr(aberrormsg, gep_params, 157 array_lengthof(gep_params)); 158 159 Value *puts_params[] = { 160 msgptr 161 }; 162 163 CallInst *puts_call = 164 new CallInst(puts_func, 165 puts_params, array_endof(puts_params), 166 "", aberrorbb); 167 puts_call->setTailCall(false); 168 } 169 170 //br label %brainf.end 171 new BranchInst(endbb, aberrorbb); 172 } 173} 174 175void BrainF::readloop(PHINode *phi, BasicBlock *oldbb, BasicBlock *testbb) { 176 Symbol cursym = SYM_NONE; 177 int curvalue = 0; 178 Symbol nextsym = SYM_NONE; 179 int nextvalue = 0; 180 char c; 181 int loop; 182 int direction; 183 184 while(cursym != SYM_EOF && cursym != SYM_ENDLOOP) { 185 // Write out commands 186 switch(cursym) { 187 case SYM_NONE: 188 // Do nothing 189 break; 190 191 case SYM_READ: 192 { 193 //%tape.%d = call i32 @getchar() 194 CallInst *getchar_call = builder->CreateCall(getchar_func, tapereg); 195 getchar_call->setTailCall(false); 196 Value *tape_0 = getchar_call; 197 198 //%tape.%d = trunc i32 %tape.%d to i8 199 TruncInst *tape_1 = builder-> 200 CreateTrunc(tape_0, IntegerType::Int8Ty, tapereg); 201 202 //store i8 %tape.%d, i8 *%head.%d 203 builder->CreateStore(tape_1, curhead); 204 } 205 break; 206 207 case SYM_WRITE: 208 { 209 //%tape.%d = load i8 *%head.%d 210 LoadInst *tape_0 = builder->CreateLoad(curhead, tapereg); 211 212 //%tape.%d = sext i8 %tape.%d to i32 213 SExtInst *tape_1 = builder-> 214 CreateSExt(tape_0, IntegerType::Int32Ty, tapereg); 215 216 //call i32 @putchar(i32 %tape.%d) 217 Value *putchar_params[] = { 218 tape_1 219 }; 220 CallInst *putchar_call = builder-> 221 CreateCall(putchar_func, 222 putchar_params, array_endof(putchar_params)); 223 putchar_call->setTailCall(false); 224 } 225 break; 226 227 case SYM_MOVE: 228 { 229 //%head.%d = getelementptr i8 *%head.%d, i32 %d 230 curhead = builder-> 231 CreateGEP(curhead, ConstantInt::get(APInt(32, curvalue)), 232 headreg); 233 234 //Error block for array out of bounds 235 if (comflag & flag_arraybounds) 236 { 237 //%test.%d = icmp uge i8 *%head.%d, %arrmax 238 ICmpInst *test_0 = builder-> 239 CreateICmpUGE(curhead, ptr_arrmax, testreg); 240 241 //%test.%d = icmp ult i8 *%head.%d, %arr 242 ICmpInst *test_1 = builder-> 243 CreateICmpULT(curhead, ptr_arr, testreg); 244 245 //%test.%d = or i1 %test.%d, %test.%d 246 BinaryOperator *test_2 = builder-> 247 CreateOr(test_0, test_1, testreg); 248 249 //br i1 %test.%d, label %main.%d, label %main.%d 250 BasicBlock *nextbb = new BasicBlock(label, brainf_func); 251 builder->CreateCondBr(test_2, aberrorbb, nextbb); 252 253 //main.%d: 254 builder->SetInsertPoint(nextbb); 255 } 256 } 257 break; 258 259 case SYM_CHANGE: 260 { 261 //%tape.%d = load i8 *%head.%d 262 LoadInst *tape_0 = builder->CreateLoad(curhead, tapereg); 263 264 //%tape.%d = add i8 %tape.%d, %d 265 BinaryOperator *tape_1 = builder-> 266 CreateAdd(tape_0, ConstantInt::get(APInt(8, curvalue)), tapereg); 267 268 //store i8 %tape.%d, i8 *%head.%d\n" 269 builder->CreateStore(tape_1, curhead); 270 } 271 break; 272 273 case SYM_LOOP: 274 { 275 //br label %main.%d 276 BasicBlock *testbb = new BasicBlock(label, brainf_func); 277 builder->CreateBr(testbb); 278 279 //main.%d: 280 BasicBlock *bb_0 = builder->GetInsertBlock(); 281 BasicBlock *bb_1 = new BasicBlock(label, brainf_func); 282 builder->SetInsertPoint(bb_1); 283 284 //Make part of PHI instruction now, wait until end of loop to finish 285 PHINode *phi_0 = new PHINode(PointerType::getUnqual(IntegerType::Int8Ty), 286 headreg, testbb); 287 phi_0->reserveOperandSpace(2); 288 phi_0->addIncoming(curhead, bb_0); 289 curhead = phi_0; 290 291 readloop(phi_0, bb_1, testbb); 292 } 293 break; 294 295 default: 296 cerr<<"Error: Unknown symbol.\n"; 297 abort(); 298 break; 299 } 300 301 cursym = nextsym; 302 curvalue = nextvalue; 303 nextsym = SYM_NONE; 304 305 // Reading stdin loop 306 loop = (cursym == SYM_NONE) 307 || (cursym == SYM_MOVE) 308 || (cursym == SYM_CHANGE); 309 while(loop) { 310 *in>>c; 311 if (in->eof()) { 312 if (cursym == SYM_NONE) { 313 cursym = SYM_EOF; 314 } else { 315 nextsym = SYM_EOF; 316 } 317 loop = 0; 318 } else { 319 direction = 1; 320 switch(c) { 321 case '-': 322 direction = -1; 323 // Fall through 324 325 case '+': 326 if (cursym == SYM_CHANGE) { 327 curvalue += direction; 328 // loop = 1 329 } else { 330 if (cursym == SYM_NONE) { 331 cursym = SYM_CHANGE; 332 curvalue = direction; 333 // loop = 1 334 } else { 335 nextsym = SYM_CHANGE; 336 nextvalue = direction; 337 loop = 0; 338 } 339 } 340 break; 341 342 case '<': 343 direction = -1; 344 // Fall through 345 346 case '>': 347 if (cursym == SYM_MOVE) { 348 curvalue += direction; 349 // loop = 1 350 } else { 351 if (cursym == SYM_NONE) { 352 cursym = SYM_MOVE; 353 curvalue = direction; 354 // loop = 1 355 } else { 356 nextsym = SYM_MOVE; 357 nextvalue = direction; 358 loop = 0; 359 } 360 } 361 break; 362 363 case ',': 364 if (cursym == SYM_NONE) { 365 cursym = SYM_READ; 366 } else { 367 nextsym = SYM_READ; 368 } 369 loop = 0; 370 break; 371 372 case '.': 373 if (cursym == SYM_NONE) { 374 cursym = SYM_WRITE; 375 } else { 376 nextsym = SYM_WRITE; 377 } 378 loop = 0; 379 break; 380 381 case '[': 382 if (cursym == SYM_NONE) { 383 cursym = SYM_LOOP; 384 } else { 385 nextsym = SYM_LOOP; 386 } 387 loop = 0; 388 break; 389 390 case ']': 391 if (cursym == SYM_NONE) { 392 cursym = SYM_ENDLOOP; 393 } else { 394 nextsym = SYM_ENDLOOP; 395 } 396 loop = 0; 397 break; 398 399 // Ignore other characters 400 default: 401 break; 402 } 403 } 404 } 405 } 406 407 if (cursym == SYM_ENDLOOP) { 408 if (!phi) { 409 cerr<<"Error: Extra ']'\n"; 410 abort(); 411 } 412 413 // Write loop test 414 { 415 //br label %main.%d 416 builder->CreateBr(testbb); 417 418 //main.%d: 419 420 //%head.%d = phi i8 *[%head.%d, %main.%d], [%head.%d, %main.%d] 421 //Finish phi made at beginning of loop 422 phi->addIncoming(curhead, builder->GetInsertBlock()); 423 Value *head_0 = phi; 424 425 //%tape.%d = load i8 *%head.%d 426 LoadInst *tape_0 = new LoadInst(head_0, tapereg, testbb); 427 428 //%test.%d = icmp eq i8 %tape.%d, 0 429 ICmpInst *test_0 = new ICmpInst(ICmpInst::ICMP_EQ, tape_0, 430 ConstantInt::get(APInt(8, 0)), testreg, 431 testbb); 432 433 //br i1 %test.%d, label %main.%d, label %main.%d 434 BasicBlock *bb_0 = new BasicBlock(label, brainf_func); 435 new BranchInst(bb_0, oldbb, test_0, testbb); 436 437 //main.%d: 438 builder->SetInsertPoint(bb_0); 439 440 //%head.%d = phi i8 *[%head.%d, %main.%d] 441 PHINode *phi_1 = builder-> 442 CreatePHI(PointerType::getUnqual(IntegerType::Int8Ty), headreg); 443 phi_1->reserveOperandSpace(1); 444 phi_1->addIncoming(head_0, testbb); 445 curhead = phi_1; 446 } 447 448 return; 449 } 450 451 //End of the program, so go to return block 452 builder->CreateBr(endbb); 453 454 if (phi) { 455 cerr<<"Error: Missing ']'\n"; 456 abort(); 457 } 458} 459