1 //===-- Function.cpp - Implement the Global object classes ----------------===// 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 Function class for the VMCore library. 11 // 12 //===----------------------------------------------------------------------===// 13 14 #include "llvm/Module.h" 15 #include "llvm/DerivedTypes.h" 16 #include "llvm/IntrinsicInst.h" 17 #include "llvm/LLVMContext.h" 18 #include "llvm/CodeGen/ValueTypes.h" 19 #include "llvm/Support/CallSite.h" 20 #include "llvm/Support/InstIterator.h" 21 #include "llvm/Support/LeakDetector.h" 22 #include "llvm/Support/ManagedStatic.h" 23 #include "llvm/Support/StringPool.h" 24 #include "llvm/Support/RWMutex.h" 25 #include "llvm/Support/Threading.h" 26 #include "SymbolTableListTraitsImpl.h" 27 #include "llvm/ADT/DenseMap.h" 28 #include "llvm/ADT/STLExtras.h" 29 #include "llvm/ADT/StringExtras.h" 30 using namespace llvm; 31 32 33 // Explicit instantiations of SymbolTableListTraits since some of the methods 34 // are not in the public header file... 35 template class llvm::SymbolTableListTraits<Argument, Function>; 36 template class llvm::SymbolTableListTraits<BasicBlock, Function>; 37 38 //===----------------------------------------------------------------------===// 39 // Argument Implementation 40 //===----------------------------------------------------------------------===// 41 42 Argument::Argument(Type *Ty, const Twine &Name, Function *Par) 43 : Value(Ty, Value::ArgumentVal) { 44 Parent = 0; 45 46 // Make sure that we get added to a function 47 LeakDetector::addGarbageObject(this); 48 49 if (Par) 50 Par->getArgumentList().push_back(this); 51 setName(Name); 52 } 53 54 void Argument::setParent(Function *parent) { 55 if (getParent()) 56 LeakDetector::addGarbageObject(this); 57 Parent = parent; 58 if (getParent()) 59 LeakDetector::removeGarbageObject(this); 60 } 61 62 /// getArgNo - Return the index of this formal argument in its containing 63 /// function. For example in "void foo(int a, float b)" a is 0 and b is 1. 64 unsigned Argument::getArgNo() const { 65 const Function *F = getParent(); 66 assert(F && "Argument is not in a function"); 67 68 Function::const_arg_iterator AI = F->arg_begin(); 69 unsigned ArgIdx = 0; 70 for (; &*AI != this; ++AI) 71 ++ArgIdx; 72 73 return ArgIdx; 74 } 75 76 /// hasByValAttr - Return true if this argument has the byval attribute on it 77 /// in its containing function. 78 bool Argument::hasByValAttr() const { 79 if (!getType()->isPointerTy()) return false; 80 return getParent()->paramHasAttr(getArgNo()+1, Attribute::ByVal); 81 } 82 83 unsigned Argument::getParamAlignment() const { 84 assert(getType()->isPointerTy() && "Only pointers have alignments"); 85 return getParent()->getParamAlignment(getArgNo()+1); 86 87 } 88 89 /// hasNestAttr - Return true if this argument has the nest attribute on 90 /// it in its containing function. 91 bool Argument::hasNestAttr() const { 92 if (!getType()->isPointerTy()) return false; 93 return getParent()->paramHasAttr(getArgNo()+1, Attribute::Nest); 94 } 95 96 /// hasNoAliasAttr - Return true if this argument has the noalias attribute on 97 /// it in its containing function. 98 bool Argument::hasNoAliasAttr() const { 99 if (!getType()->isPointerTy()) return false; 100 return getParent()->paramHasAttr(getArgNo()+1, Attribute::NoAlias); 101 } 102 103 /// hasNoCaptureAttr - Return true if this argument has the nocapture attribute 104 /// on it in its containing function. 105 bool Argument::hasNoCaptureAttr() const { 106 if (!getType()->isPointerTy()) return false; 107 return getParent()->paramHasAttr(getArgNo()+1, Attribute::NoCapture); 108 } 109 110 /// hasSRetAttr - Return true if this argument has the sret attribute on 111 /// it in its containing function. 112 bool Argument::hasStructRetAttr() const { 113 if (!getType()->isPointerTy()) return false; 114 if (this != getParent()->arg_begin()) 115 return false; // StructRet param must be first param 116 return getParent()->paramHasAttr(1, Attribute::StructRet); 117 } 118 119 /// addAttr - Add a Attribute to an argument 120 void Argument::addAttr(Attributes attr) { 121 getParent()->addAttribute(getArgNo() + 1, attr); 122 } 123 124 /// removeAttr - Remove a Attribute from an argument 125 void Argument::removeAttr(Attributes attr) { 126 getParent()->removeAttribute(getArgNo() + 1, attr); 127 } 128 129 130 //===----------------------------------------------------------------------===// 131 // Helper Methods in Function 132 //===----------------------------------------------------------------------===// 133 134 LLVMContext &Function::getContext() const { 135 return getType()->getContext(); 136 } 137 138 FunctionType *Function::getFunctionType() const { 139 return cast<FunctionType>(getType()->getElementType()); 140 } 141 142 bool Function::isVarArg() const { 143 return getFunctionType()->isVarArg(); 144 } 145 146 Type *Function::getReturnType() const { 147 return getFunctionType()->getReturnType(); 148 } 149 150 void Function::removeFromParent() { 151 getParent()->getFunctionList().remove(this); 152 } 153 154 void Function::eraseFromParent() { 155 getParent()->getFunctionList().erase(this); 156 } 157 158 //===----------------------------------------------------------------------===// 159 // Function Implementation 160 //===----------------------------------------------------------------------===// 161 162 Function::Function(FunctionType *Ty, LinkageTypes Linkage, 163 const Twine &name, Module *ParentModule) 164 : GlobalValue(PointerType::getUnqual(Ty), 165 Value::FunctionVal, 0, 0, Linkage, name) { 166 assert(FunctionType::isValidReturnType(getReturnType()) && 167 "invalid return type"); 168 SymTab = new ValueSymbolTable(); 169 170 // If the function has arguments, mark them as lazily built. 171 if (Ty->getNumParams()) 172 setValueSubclassData(1); // Set the "has lazy arguments" bit. 173 174 // Make sure that we get added to a function 175 LeakDetector::addGarbageObject(this); 176 177 if (ParentModule) 178 ParentModule->getFunctionList().push_back(this); 179 180 // Ensure intrinsics have the right parameter attributes. 181 intrinsicID = initIntrinsicID(); 182 if (intrinsicID) 183 setAttributes(Intrinsic::getAttributes(Intrinsic::ID(intrinsicID))); 184 } 185 186 Function::~Function() { 187 dropAllReferences(); // After this it is safe to delete instructions. 188 189 // Delete all of the method arguments and unlink from symbol table... 190 ArgumentList.clear(); 191 delete SymTab; 192 193 // Remove the function from the on-the-side GC table. 194 clearGC(); 195 } 196 197 void Function::BuildLazyArguments() const { 198 // Create the arguments vector, all arguments start out unnamed. 199 FunctionType *FT = getFunctionType(); 200 for (unsigned i = 0, e = FT->getNumParams(); i != e; ++i) { 201 assert(!FT->getParamType(i)->isVoidTy() && 202 "Cannot have void typed arguments!"); 203 ArgumentList.push_back(new Argument(FT->getParamType(i))); 204 } 205 206 // Clear the lazy arguments bit. 207 unsigned SDC = getSubclassDataFromValue(); 208 const_cast<Function*>(this)->setValueSubclassData(SDC &= ~1); 209 } 210 211 size_t Function::arg_size() const { 212 return getFunctionType()->getNumParams(); 213 } 214 bool Function::arg_empty() const { 215 return getFunctionType()->getNumParams() == 0; 216 } 217 218 void Function::setParent(Module *parent) { 219 if (getParent()) 220 LeakDetector::addGarbageObject(this); 221 Parent = parent; 222 if (getParent()) 223 LeakDetector::removeGarbageObject(this); 224 } 225 226 // dropAllReferences() - This function causes all the subinstructions to "let 227 // go" of all references that they are maintaining. This allows one to 228 // 'delete' a whole class at a time, even though there may be circular 229 // references... first all references are dropped, and all use counts go to 230 // zero. Then everything is deleted for real. Note that no operations are 231 // valid on an object that has "dropped all references", except operator 232 // delete. 233 // 234 void Function::dropAllReferences() { 235 for (iterator I = begin(), E = end(); I != E; ++I) 236 I->dropAllReferences(); 237 238 // Delete all basic blocks. They are now unused, except possibly by 239 // blockaddresses, but BasicBlock's destructor takes care of those. 240 while (!BasicBlocks.empty()) 241 BasicBlocks.begin()->eraseFromParent(); 242 } 243 244 void Function::addAttribute(unsigned i, Attributes attr) { 245 AttrListPtr PAL = getAttributes(); 246 PAL = PAL.addAttr(i, attr); 247 setAttributes(PAL); 248 } 249 250 void Function::removeAttribute(unsigned i, Attributes attr) { 251 AttrListPtr PAL = getAttributes(); 252 PAL = PAL.removeAttr(i, attr); 253 setAttributes(PAL); 254 } 255 256 // Maintain the GC name for each function in an on-the-side table. This saves 257 // allocating an additional word in Function for programs which do not use GC 258 // (i.e., most programs) at the cost of increased overhead for clients which do 259 // use GC. 260 static DenseMap<const Function*,PooledStringPtr> *GCNames; 261 static StringPool *GCNamePool; 262 static ManagedStatic<sys::SmartRWMutex<true> > GCLock; 263 264 bool Function::hasGC() const { 265 sys::SmartScopedReader<true> Reader(*GCLock); 266 return GCNames && GCNames->count(this); 267 } 268 269 const char *Function::getGC() const { 270 assert(hasGC() && "Function has no collector"); 271 sys::SmartScopedReader<true> Reader(*GCLock); 272 return *(*GCNames)[this]; 273 } 274 275 void Function::setGC(const char *Str) { 276 sys::SmartScopedWriter<true> Writer(*GCLock); 277 if (!GCNamePool) 278 GCNamePool = new StringPool(); 279 if (!GCNames) 280 GCNames = new DenseMap<const Function*,PooledStringPtr>(); 281 (*GCNames)[this] = GCNamePool->intern(Str); 282 } 283 284 void Function::clearGC() { 285 sys::SmartScopedWriter<true> Writer(*GCLock); 286 if (GCNames) { 287 GCNames->erase(this); 288 if (GCNames->empty()) { 289 delete GCNames; 290 GCNames = 0; 291 if (GCNamePool->empty()) { 292 delete GCNamePool; 293 GCNamePool = 0; 294 } 295 } 296 } 297 } 298 299 /// copyAttributesFrom - copy all additional attributes (those not needed to 300 /// create a Function) from the Function Src to this one. 301 void Function::copyAttributesFrom(const GlobalValue *Src) { 302 assert(isa<Function>(Src) && "Expected a Function!"); 303 GlobalValue::copyAttributesFrom(Src); 304 const Function *SrcF = cast<Function>(Src); 305 setCallingConv(SrcF->getCallingConv()); 306 setAttributes(SrcF->getAttributes()); 307 if (SrcF->hasGC()) 308 setGC(SrcF->getGC()); 309 else 310 clearGC(); 311 } 312 313 /// initIntrinsicID - This method returns the ID number of the specified 314 /// function, or Intrinsic::not_intrinsic if the function is not an 315 /// intrinsic, or if the pointer is null. This value is always defined to be 316 /// zero to allow easy checking for whether a function is intrinsic or not. The 317 /// particular intrinsic functions which correspond to this value are defined in 318 /// llvm/Intrinsics.h. 319 /// 320 unsigned Function::initIntrinsicID() const { 321 const ValueName *ValName = this->getValueName(); 322 if (!ValName) 323 return 0; 324 unsigned Len = ValName->getKeyLength(); 325 const char *Name = ValName->getKeyData(); 326 327 if (Len < 5 || Name[4] != '.' || Name[0] != 'l' || Name[1] != 'l' 328 || Name[2] != 'v' || Name[3] != 'm') 329 return 0; // All intrinsics start with 'llvm.' 330 331 #define GET_FUNCTION_RECOGNIZER 332 #include "llvm/Intrinsics.gen" 333 #undef GET_FUNCTION_RECOGNIZER 334 return 0; 335 } 336 337 std::string Intrinsic::getName(ID id, ArrayRef<Type*> Tys) { 338 assert(id < num_intrinsics && "Invalid intrinsic ID!"); 339 static const char * const Table[] = { 340 "not_intrinsic", 341 #define GET_INTRINSIC_NAME_TABLE 342 #include "llvm/Intrinsics.gen" 343 #undef GET_INTRINSIC_NAME_TABLE 344 }; 345 if (Tys.empty()) 346 return Table[id]; 347 std::string Result(Table[id]); 348 for (unsigned i = 0; i < Tys.size(); ++i) { 349 if (PointerType* PTyp = dyn_cast<PointerType>(Tys[i])) { 350 Result += ".p" + llvm::utostr(PTyp->getAddressSpace()) + 351 EVT::getEVT(PTyp->getElementType()).getEVTString(); 352 } 353 else if (Tys[i]) 354 Result += "." + EVT::getEVT(Tys[i]).getEVTString(); 355 } 356 return Result; 357 } 358 359 FunctionType *Intrinsic::getType(LLVMContext &Context, 360 ID id, ArrayRef<Type*> Tys) { 361 Type *ResultTy = NULL; 362 std::vector<Type*> ArgTys; 363 bool IsVarArg = false; 364 365 #define GET_INTRINSIC_GENERATOR 366 #include "llvm/Intrinsics.gen" 367 #undef GET_INTRINSIC_GENERATOR 368 369 return FunctionType::get(ResultTy, ArgTys, IsVarArg); 370 } 371 372 bool Intrinsic::isOverloaded(ID id) { 373 static const bool OTable[] = { 374 false, 375 #define GET_INTRINSIC_OVERLOAD_TABLE 376 #include "llvm/Intrinsics.gen" 377 #undef GET_INTRINSIC_OVERLOAD_TABLE 378 }; 379 return OTable[id]; 380 } 381 382 /// This defines the "Intrinsic::getAttributes(ID id)" method. 383 #define GET_INTRINSIC_ATTRIBUTES 384 #include "llvm/Intrinsics.gen" 385 #undef GET_INTRINSIC_ATTRIBUTES 386 387 Function *Intrinsic::getDeclaration(Module *M, ID id, ArrayRef<Type*> Tys) { 388 // There can never be multiple globals with the same name of different types, 389 // because intrinsics must be a specific type. 390 return 391 cast<Function>(M->getOrInsertFunction(getName(id, Tys), 392 getType(M->getContext(), id, Tys))); 393 } 394 395 // This defines the "Intrinsic::getIntrinsicForGCCBuiltin()" method. 396 #define GET_LLVM_INTRINSIC_FOR_GCC_BUILTIN 397 #include "llvm/Intrinsics.gen" 398 #undef GET_LLVM_INTRINSIC_FOR_GCC_BUILTIN 399 400 /// hasAddressTaken - returns true if there are any uses of this function 401 /// other than direct calls or invokes to it. 402 bool Function::hasAddressTaken(const User* *PutOffender) const { 403 for (Value::const_use_iterator I = use_begin(), E = use_end(); I != E; ++I) { 404 const User *U = *I; 405 if (!isa<CallInst>(U) && !isa<InvokeInst>(U)) 406 return PutOffender ? (*PutOffender = U, true) : true; 407 ImmutableCallSite CS(cast<Instruction>(U)); 408 if (!CS.isCallee(I)) 409 return PutOffender ? (*PutOffender = U, true) : true; 410 } 411 return false; 412 } 413 414 /// callsFunctionThatReturnsTwice - Return true if the function has a call to 415 /// setjmp or other function that gcc recognizes as "returning twice". 416 /// 417 /// FIXME: Remove after <rdar://problem/8031714> is fixed. 418 /// FIXME: Is the above FIXME valid? 419 bool Function::callsFunctionThatReturnsTwice() const { 420 static const char *const ReturnsTwiceFns[] = { 421 "_setjmp", 422 "setjmp", 423 "sigsetjmp", 424 "setjmp_syscall", 425 "savectx", 426 "qsetjmp", 427 "vfork", 428 "getcontext" 429 }; 430 431 for (const_inst_iterator I = inst_begin(this), E = inst_end(this); I != E; 432 ++I) { 433 const CallInst* callInst = dyn_cast<CallInst>(&*I); 434 if (!callInst) 435 continue; 436 if (callInst->canReturnTwice()) 437 return true; 438 439 // check for known function names. 440 // FIXME: move this to clang. 441 Function *F = callInst->getCalledFunction(); 442 if (!F) 443 continue; 444 StringRef Name = F->getName(); 445 for (unsigned J = 0, e = array_lengthof(ReturnsTwiceFns); J != e; ++J) { 446 if (Name == ReturnsTwiceFns[J]) 447 return true; 448 } 449 } 450 451 return false; 452 } 453 454 // vim: sw=2 ai 455