1 //===-- Instruction.cpp - Implement the Instruction class -----------------===// 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 file implements the Instruction class for the VMCore library. 11 // 12 //===----------------------------------------------------------------------===// 13 14 #include "llvm/Instruction.h" 15 #include "llvm/Type.h" 16 #include "llvm/Instructions.h" 17 #include "llvm/Constants.h" 18 #include "llvm/Module.h" 19 #include "llvm/Support/CallSite.h" 20 #include "llvm/Support/LeakDetector.h" 21 using namespace llvm; 22 23 Instruction::Instruction(Type *ty, unsigned it, Use *Ops, unsigned NumOps, 24 Instruction *InsertBefore) 25 : User(ty, Value::InstructionVal + it, Ops, NumOps), Parent(0) { 26 // Make sure that we get added to a basicblock 27 LeakDetector::addGarbageObject(this); 28 29 // If requested, insert this instruction into a basic block... 30 if (InsertBefore) { 31 assert(InsertBefore->getParent() && 32 "Instruction to insert before is not in a basic block!"); 33 InsertBefore->getParent()->getInstList().insert(InsertBefore, this); 34 } 35 } 36 37 Instruction::Instruction(Type *ty, unsigned it, Use *Ops, unsigned NumOps, 38 BasicBlock *InsertAtEnd) 39 : User(ty, Value::InstructionVal + it, Ops, NumOps), Parent(0) { 40 // Make sure that we get added to a basicblock 41 LeakDetector::addGarbageObject(this); 42 43 // append this instruction into the basic block 44 assert(InsertAtEnd && "Basic block to append to may not be NULL!"); 45 InsertAtEnd->getInstList().push_back(this); 46 } 47 48 49 // Out of line virtual method, so the vtable, etc has a home. 50 Instruction::~Instruction() { 51 assert(Parent == 0 && "Instruction still linked in the program!"); 52 if (hasMetadataHashEntry()) 53 clearMetadataHashEntries(); 54 } 55 56 57 void Instruction::setParent(BasicBlock *P) { 58 if (getParent()) { 59 if (!P) LeakDetector::addGarbageObject(this); 60 } else { 61 if (P) LeakDetector::removeGarbageObject(this); 62 } 63 64 Parent = P; 65 } 66 67 void Instruction::removeFromParent() { 68 getParent()->getInstList().remove(this); 69 } 70 71 void Instruction::eraseFromParent() { 72 getParent()->getInstList().erase(this); 73 } 74 75 /// insertBefore - Insert an unlinked instructions into a basic block 76 /// immediately before the specified instruction. 77 void Instruction::insertBefore(Instruction *InsertPos) { 78 InsertPos->getParent()->getInstList().insert(InsertPos, this); 79 } 80 81 /// insertAfter - Insert an unlinked instructions into a basic block 82 /// immediately after the specified instruction. 83 void Instruction::insertAfter(Instruction *InsertPos) { 84 InsertPos->getParent()->getInstList().insertAfter(InsertPos, this); 85 } 86 87 /// moveBefore - Unlink this instruction from its current basic block and 88 /// insert it into the basic block that MovePos lives in, right before 89 /// MovePos. 90 void Instruction::moveBefore(Instruction *MovePos) { 91 MovePos->getParent()->getInstList().splice(MovePos,getParent()->getInstList(), 92 this); 93 } 94 95 96 const char *Instruction::getOpcodeName(unsigned OpCode) { 97 switch (OpCode) { 98 // Terminators 99 case Ret: return "ret"; 100 case Br: return "br"; 101 case Switch: return "switch"; 102 case IndirectBr: return "indirectbr"; 103 case Invoke: return "invoke"; 104 case Resume: return "resume"; 105 case Unwind: return "unwind"; 106 case Unreachable: return "unreachable"; 107 108 // Standard binary operators... 109 case Add: return "add"; 110 case FAdd: return "fadd"; 111 case Sub: return "sub"; 112 case FSub: return "fsub"; 113 case Mul: return "mul"; 114 case FMul: return "fmul"; 115 case UDiv: return "udiv"; 116 case SDiv: return "sdiv"; 117 case FDiv: return "fdiv"; 118 case URem: return "urem"; 119 case SRem: return "srem"; 120 case FRem: return "frem"; 121 122 // Logical operators... 123 case And: return "and"; 124 case Or : return "or"; 125 case Xor: return "xor"; 126 127 // Memory instructions... 128 case Alloca: return "alloca"; 129 case Load: return "load"; 130 case Store: return "store"; 131 case AtomicCmpXchg: return "cmpxchg"; 132 case AtomicRMW: return "atomicrmw"; 133 case Fence: return "fence"; 134 case GetElementPtr: return "getelementptr"; 135 136 // Convert instructions... 137 case Trunc: return "trunc"; 138 case ZExt: return "zext"; 139 case SExt: return "sext"; 140 case FPTrunc: return "fptrunc"; 141 case FPExt: return "fpext"; 142 case FPToUI: return "fptoui"; 143 case FPToSI: return "fptosi"; 144 case UIToFP: return "uitofp"; 145 case SIToFP: return "sitofp"; 146 case IntToPtr: return "inttoptr"; 147 case PtrToInt: return "ptrtoint"; 148 case BitCast: return "bitcast"; 149 150 // Other instructions... 151 case ICmp: return "icmp"; 152 case FCmp: return "fcmp"; 153 case PHI: return "phi"; 154 case Select: return "select"; 155 case Call: return "call"; 156 case Shl: return "shl"; 157 case LShr: return "lshr"; 158 case AShr: return "ashr"; 159 case VAArg: return "va_arg"; 160 case ExtractElement: return "extractelement"; 161 case InsertElement: return "insertelement"; 162 case ShuffleVector: return "shufflevector"; 163 case ExtractValue: return "extractvalue"; 164 case InsertValue: return "insertvalue"; 165 case LandingPad: return "landingpad"; 166 167 default: return "<Invalid operator> "; 168 } 169 170 return 0; 171 } 172 173 /// isIdenticalTo - Return true if the specified instruction is exactly 174 /// identical to the current one. This means that all operands match and any 175 /// extra information (e.g. load is volatile) agree. 176 bool Instruction::isIdenticalTo(const Instruction *I) const { 177 return isIdenticalToWhenDefined(I) && 178 SubclassOptionalData == I->SubclassOptionalData; 179 } 180 181 /// isIdenticalToWhenDefined - This is like isIdenticalTo, except that it 182 /// ignores the SubclassOptionalData flags, which specify conditions 183 /// under which the instruction's result is undefined. 184 bool Instruction::isIdenticalToWhenDefined(const Instruction *I) const { 185 if (getOpcode() != I->getOpcode() || 186 getNumOperands() != I->getNumOperands() || 187 getType() != I->getType()) 188 return false; 189 190 // We have two instructions of identical opcode and #operands. Check to see 191 // if all operands are the same. 192 for (unsigned i = 0, e = getNumOperands(); i != e; ++i) 193 if (getOperand(i) != I->getOperand(i)) 194 return false; 195 196 // Check special state that is a part of some instructions. 197 if (const LoadInst *LI = dyn_cast<LoadInst>(this)) 198 return LI->isVolatile() == cast<LoadInst>(I)->isVolatile() && 199 LI->getAlignment() == cast<LoadInst>(I)->getAlignment() && 200 LI->getOrdering() == cast<LoadInst>(I)->getOrdering() && 201 LI->getSynchScope() == cast<LoadInst>(I)->getSynchScope(); 202 if (const StoreInst *SI = dyn_cast<StoreInst>(this)) 203 return SI->isVolatile() == cast<StoreInst>(I)->isVolatile() && 204 SI->getAlignment() == cast<StoreInst>(I)->getAlignment() && 205 SI->getOrdering() == cast<StoreInst>(I)->getOrdering() && 206 SI->getSynchScope() == cast<StoreInst>(I)->getSynchScope(); 207 if (const CmpInst *CI = dyn_cast<CmpInst>(this)) 208 return CI->getPredicate() == cast<CmpInst>(I)->getPredicate(); 209 if (const CallInst *CI = dyn_cast<CallInst>(this)) 210 return CI->isTailCall() == cast<CallInst>(I)->isTailCall() && 211 CI->getCallingConv() == cast<CallInst>(I)->getCallingConv() && 212 CI->getAttributes() == cast<CallInst>(I)->getAttributes(); 213 if (const InvokeInst *CI = dyn_cast<InvokeInst>(this)) 214 return CI->getCallingConv() == cast<InvokeInst>(I)->getCallingConv() && 215 CI->getAttributes() == cast<InvokeInst>(I)->getAttributes(); 216 if (const InsertValueInst *IVI = dyn_cast<InsertValueInst>(this)) 217 return IVI->getIndices() == cast<InsertValueInst>(I)->getIndices(); 218 if (const ExtractValueInst *EVI = dyn_cast<ExtractValueInst>(this)) 219 return EVI->getIndices() == cast<ExtractValueInst>(I)->getIndices(); 220 if (const FenceInst *FI = dyn_cast<FenceInst>(this)) 221 return FI->getOrdering() == cast<FenceInst>(FI)->getOrdering() && 222 FI->getSynchScope() == cast<FenceInst>(FI)->getSynchScope(); 223 if (const AtomicCmpXchgInst *CXI = dyn_cast<AtomicCmpXchgInst>(this)) 224 return CXI->isVolatile() == cast<AtomicCmpXchgInst>(I)->isVolatile() && 225 CXI->getOrdering() == cast<AtomicCmpXchgInst>(I)->getOrdering() && 226 CXI->getSynchScope() == cast<AtomicCmpXchgInst>(I)->getSynchScope(); 227 if (const AtomicRMWInst *RMWI = dyn_cast<AtomicRMWInst>(this)) 228 return RMWI->getOperation() == cast<AtomicRMWInst>(I)->getOperation() && 229 RMWI->isVolatile() == cast<AtomicRMWInst>(I)->isVolatile() && 230 RMWI->getOrdering() == cast<AtomicRMWInst>(I)->getOrdering() && 231 RMWI->getSynchScope() == cast<AtomicRMWInst>(I)->getSynchScope(); 232 233 return true; 234 } 235 236 // isSameOperationAs 237 // This should be kept in sync with isEquivalentOperation in 238 // lib/Transforms/IPO/MergeFunctions.cpp. 239 bool Instruction::isSameOperationAs(const Instruction *I) const { 240 if (getOpcode() != I->getOpcode() || 241 getNumOperands() != I->getNumOperands() || 242 getType() != I->getType()) 243 return false; 244 245 // We have two instructions of identical opcode and #operands. Check to see 246 // if all operands are the same type 247 for (unsigned i = 0, e = getNumOperands(); i != e; ++i) 248 if (getOperand(i)->getType() != I->getOperand(i)->getType()) 249 return false; 250 251 // Check special state that is a part of some instructions. 252 if (const LoadInst *LI = dyn_cast<LoadInst>(this)) 253 return LI->isVolatile() == cast<LoadInst>(I)->isVolatile() && 254 LI->getAlignment() == cast<LoadInst>(I)->getAlignment() && 255 LI->getOrdering() == cast<LoadInst>(I)->getOrdering() && 256 LI->getSynchScope() == cast<LoadInst>(I)->getSynchScope(); 257 if (const StoreInst *SI = dyn_cast<StoreInst>(this)) 258 return SI->isVolatile() == cast<StoreInst>(I)->isVolatile() && 259 SI->getAlignment() == cast<StoreInst>(I)->getAlignment() && 260 SI->getOrdering() == cast<StoreInst>(I)->getOrdering() && 261 SI->getSynchScope() == cast<StoreInst>(I)->getSynchScope(); 262 if (const CmpInst *CI = dyn_cast<CmpInst>(this)) 263 return CI->getPredicate() == cast<CmpInst>(I)->getPredicate(); 264 if (const CallInst *CI = dyn_cast<CallInst>(this)) 265 return CI->isTailCall() == cast<CallInst>(I)->isTailCall() && 266 CI->getCallingConv() == cast<CallInst>(I)->getCallingConv() && 267 CI->getAttributes() == cast<CallInst>(I)->getAttributes(); 268 if (const InvokeInst *CI = dyn_cast<InvokeInst>(this)) 269 return CI->getCallingConv() == cast<InvokeInst>(I)->getCallingConv() && 270 CI->getAttributes() == 271 cast<InvokeInst>(I)->getAttributes(); 272 if (const InsertValueInst *IVI = dyn_cast<InsertValueInst>(this)) 273 return IVI->getIndices() == cast<InsertValueInst>(I)->getIndices(); 274 if (const ExtractValueInst *EVI = dyn_cast<ExtractValueInst>(this)) 275 return EVI->getIndices() == cast<ExtractValueInst>(I)->getIndices(); 276 if (const FenceInst *FI = dyn_cast<FenceInst>(this)) 277 return FI->getOrdering() == cast<FenceInst>(I)->getOrdering() && 278 FI->getSynchScope() == cast<FenceInst>(I)->getSynchScope(); 279 if (const AtomicCmpXchgInst *CXI = dyn_cast<AtomicCmpXchgInst>(this)) 280 return CXI->isVolatile() == cast<AtomicCmpXchgInst>(I)->isVolatile() && 281 CXI->getOrdering() == cast<AtomicCmpXchgInst>(I)->getOrdering() && 282 CXI->getSynchScope() == cast<AtomicCmpXchgInst>(I)->getSynchScope(); 283 if (const AtomicRMWInst *RMWI = dyn_cast<AtomicRMWInst>(this)) 284 return RMWI->getOperation() == cast<AtomicRMWInst>(I)->getOperation() && 285 RMWI->isVolatile() == cast<AtomicRMWInst>(I)->isVolatile() && 286 RMWI->getOrdering() == cast<AtomicRMWInst>(I)->getOrdering() && 287 RMWI->getSynchScope() == cast<AtomicRMWInst>(I)->getSynchScope(); 288 289 return true; 290 } 291 292 /// isUsedOutsideOfBlock - Return true if there are any uses of I outside of the 293 /// specified block. Note that PHI nodes are considered to evaluate their 294 /// operands in the corresponding predecessor block. 295 bool Instruction::isUsedOutsideOfBlock(const BasicBlock *BB) const { 296 for (const_use_iterator UI = use_begin(), E = use_end(); UI != E; ++UI) { 297 // PHI nodes uses values in the corresponding predecessor block. For other 298 // instructions, just check to see whether the parent of the use matches up. 299 const User *U = *UI; 300 const PHINode *PN = dyn_cast<PHINode>(U); 301 if (PN == 0) { 302 if (cast<Instruction>(U)->getParent() != BB) 303 return true; 304 continue; 305 } 306 307 if (PN->getIncomingBlock(UI) != BB) 308 return true; 309 } 310 return false; 311 } 312 313 /// mayReadFromMemory - Return true if this instruction may read memory. 314 /// 315 bool Instruction::mayReadFromMemory() const { 316 switch (getOpcode()) { 317 default: return false; 318 case Instruction::VAArg: 319 case Instruction::Load: 320 case Instruction::Fence: // FIXME: refine definition of mayReadFromMemory 321 case Instruction::AtomicCmpXchg: 322 case Instruction::AtomicRMW: 323 return true; 324 case Instruction::Call: 325 return !cast<CallInst>(this)->doesNotAccessMemory(); 326 case Instruction::Invoke: 327 return !cast<InvokeInst>(this)->doesNotAccessMemory(); 328 case Instruction::Store: 329 return !cast<StoreInst>(this)->isUnordered(); 330 } 331 } 332 333 /// mayWriteToMemory - Return true if this instruction may modify memory. 334 /// 335 bool Instruction::mayWriteToMemory() const { 336 switch (getOpcode()) { 337 default: return false; 338 case Instruction::Fence: // FIXME: refine definition of mayWriteToMemory 339 case Instruction::Store: 340 case Instruction::VAArg: 341 case Instruction::AtomicCmpXchg: 342 case Instruction::AtomicRMW: 343 return true; 344 case Instruction::Call: 345 return !cast<CallInst>(this)->onlyReadsMemory(); 346 case Instruction::Invoke: 347 return !cast<InvokeInst>(this)->onlyReadsMemory(); 348 case Instruction::Load: 349 return !cast<LoadInst>(this)->isUnordered(); 350 } 351 } 352 353 /// mayThrow - Return true if this instruction may throw an exception. 354 /// 355 bool Instruction::mayThrow() const { 356 if (const CallInst *CI = dyn_cast<CallInst>(this)) 357 return !CI->doesNotThrow(); 358 return isa<ResumeInst>(this); 359 } 360 361 /// isAssociative - Return true if the instruction is associative: 362 /// 363 /// Associative operators satisfy: x op (y op z) === (x op y) op z 364 /// 365 /// In LLVM, the Add, Mul, And, Or, and Xor operators are associative. 366 /// 367 bool Instruction::isAssociative(unsigned Opcode) { 368 return Opcode == And || Opcode == Or || Opcode == Xor || 369 Opcode == Add || Opcode == Mul; 370 } 371 372 /// isCommutative - Return true if the instruction is commutative: 373 /// 374 /// Commutative operators satisfy: (x op y) === (y op x) 375 /// 376 /// In LLVM, these are the associative operators, plus SetEQ and SetNE, when 377 /// applied to any type. 378 /// 379 bool Instruction::isCommutative(unsigned op) { 380 switch (op) { 381 case Add: 382 case FAdd: 383 case Mul: 384 case FMul: 385 case And: 386 case Or: 387 case Xor: 388 return true; 389 default: 390 return false; 391 } 392 } 393 394 bool Instruction::isSafeToSpeculativelyExecute() const { 395 for (unsigned i = 0, e = getNumOperands(); i != e; ++i) 396 if (Constant *C = dyn_cast<Constant>(getOperand(i))) 397 if (C->canTrap()) 398 return false; 399 400 switch (getOpcode()) { 401 default: 402 return true; 403 case UDiv: 404 case URem: { 405 // x / y is undefined if y == 0, but calcuations like x / 3 are safe. 406 ConstantInt *Op = dyn_cast<ConstantInt>(getOperand(1)); 407 return Op && !Op->isNullValue(); 408 } 409 case SDiv: 410 case SRem: { 411 // x / y is undefined if y == 0, and might be undefined if y == -1, 412 // but calcuations like x / 3 are safe. 413 ConstantInt *Op = dyn_cast<ConstantInt>(getOperand(1)); 414 return Op && !Op->isNullValue() && !Op->isAllOnesValue(); 415 } 416 case Load: { 417 const LoadInst *LI = cast<LoadInst>(this); 418 if (!LI->isUnordered()) 419 return false; 420 return LI->getPointerOperand()->isDereferenceablePointer(); 421 } 422 case Call: 423 return false; // The called function could have undefined behavior or 424 // side-effects. 425 // FIXME: We should special-case some intrinsics (bswap, 426 // overflow-checking arithmetic, etc.) 427 case VAArg: 428 case Alloca: 429 case Invoke: 430 case PHI: 431 case Store: 432 case Ret: 433 case Br: 434 case IndirectBr: 435 case Switch: 436 case Unwind: 437 case Unreachable: 438 case Fence: 439 case LandingPad: 440 case AtomicRMW: 441 case AtomicCmpXchg: 442 case Resume: 443 return false; // Misc instructions which have effects 444 } 445 } 446 447 Instruction *Instruction::clone() const { 448 Instruction *New = clone_impl(); 449 New->SubclassOptionalData = SubclassOptionalData; 450 if (!hasMetadata()) 451 return New; 452 453 // Otherwise, enumerate and copy over metadata from the old instruction to the 454 // new one. 455 SmallVector<std::pair<unsigned, MDNode*>, 4> TheMDs; 456 getAllMetadataOtherThanDebugLoc(TheMDs); 457 for (unsigned i = 0, e = TheMDs.size(); i != e; ++i) 458 New->setMetadata(TheMDs[i].first, TheMDs[i].second); 459 460 New->setDebugLoc(getDebugLoc()); 461 return New; 462 } 463
