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 void Argument::anchor() { } 43 44 Argument::Argument(Type *Ty, const Twine &Name, Function *Par) 45 : Value(Ty, Value::ArgumentVal) { 46 Parent = 0; 47 48 // Make sure that we get added to a function 49 LeakDetector::addGarbageObject(this); 50 51 if (Par) 52 Par->getArgumentList().push_back(this); 53 setName(Name); 54 } 55 56 void Argument::setParent(Function *parent) { 57 if (getParent()) 58 LeakDetector::addGarbageObject(this); 59 Parent = parent; 60 if (getParent()) 61 LeakDetector::removeGarbageObject(this); 62 } 63 64 /// getArgNo - Return the index of this formal argument in its containing 65 /// function. For example in "void foo(int a, float b)" a is 0 and b is 1. 66 unsigned Argument::getArgNo() const { 67 const Function *F = getParent(); 68 assert(F && "Argument is not in a function"); 69 70 Function::const_arg_iterator AI = F->arg_begin(); 71 unsigned ArgIdx = 0; 72 for (; &*AI != this; ++AI) 73 ++ArgIdx; 74 75 return ArgIdx; 76 } 77 78 /// hasByValAttr - Return true if this argument has the byval attribute on it 79 /// in its containing function. 80 bool Argument::hasByValAttr() const { 81 if (!getType()->isPointerTy()) return false; 82 return getParent()->paramHasAttr(getArgNo()+1, Attribute::ByVal); 83 } 84 85 unsigned Argument::getParamAlignment() const { 86 assert(getType()->isPointerTy() && "Only pointers have alignments"); 87 return getParent()->getParamAlignment(getArgNo()+1); 88 89 } 90 91 /// hasNestAttr - Return true if this argument has the nest attribute on 92 /// it in its containing function. 93 bool Argument::hasNestAttr() const { 94 if (!getType()->isPointerTy()) return false; 95 return getParent()->paramHasAttr(getArgNo()+1, Attribute::Nest); 96 } 97 98 /// hasNoAliasAttr - Return true if this argument has the noalias attribute on 99 /// it in its containing function. 100 bool Argument::hasNoAliasAttr() const { 101 if (!getType()->isPointerTy()) return false; 102 return getParent()->paramHasAttr(getArgNo()+1, Attribute::NoAlias); 103 } 104 105 /// hasNoCaptureAttr - Return true if this argument has the nocapture attribute 106 /// on it in its containing function. 107 bool Argument::hasNoCaptureAttr() const { 108 if (!getType()->isPointerTy()) return false; 109 return getParent()->paramHasAttr(getArgNo()+1, Attribute::NoCapture); 110 } 111 112 /// hasSRetAttr - Return true if this argument has the sret attribute on 113 /// it in its containing function. 114 bool Argument::hasStructRetAttr() const { 115 if (!getType()->isPointerTy()) return false; 116 if (this != getParent()->arg_begin()) 117 return false; // StructRet param must be first param 118 return getParent()->paramHasAttr(1, Attribute::StructRet); 119 } 120 121 /// addAttr - Add a Attribute to an argument 122 void Argument::addAttr(Attributes attr) { 123 getParent()->addAttribute(getArgNo() + 1, attr); 124 } 125 126 /// removeAttr - Remove a Attribute from an argument 127 void Argument::removeAttr(Attributes attr) { 128 getParent()->removeAttribute(getArgNo() + 1, attr); 129 } 130 131 132 //===----------------------------------------------------------------------===// 133 // Helper Methods in Function 134 //===----------------------------------------------------------------------===// 135 136 LLVMContext &Function::getContext() const { 137 return getType()->getContext(); 138 } 139 140 FunctionType *Function::getFunctionType() const { 141 return cast<FunctionType>(getType()->getElementType()); 142 } 143 144 bool Function::isVarArg() const { 145 return getFunctionType()->isVarArg(); 146 } 147 148 Type *Function::getReturnType() const { 149 return getFunctionType()->getReturnType(); 150 } 151 152 void Function::removeFromParent() { 153 getParent()->getFunctionList().remove(this); 154 } 155 156 void Function::eraseFromParent() { 157 getParent()->getFunctionList().erase(this); 158 } 159 160 //===----------------------------------------------------------------------===// 161 // Function Implementation 162 //===----------------------------------------------------------------------===// 163 164 Function::Function(FunctionType *Ty, LinkageTypes Linkage, 165 const Twine &name, Module *ParentModule) 166 : GlobalValue(PointerType::getUnqual(Ty), 167 Value::FunctionVal, 0, 0, Linkage, name) { 168 assert(FunctionType::isValidReturnType(getReturnType()) && 169 "invalid return type"); 170 SymTab = new ValueSymbolTable(); 171 172 // If the function has arguments, mark them as lazily built. 173 if (Ty->getNumParams()) 174 setValueSubclassData(1); // Set the "has lazy arguments" bit. 175 176 // Make sure that we get added to a function 177 LeakDetector::addGarbageObject(this); 178 179 if (ParentModule) 180 ParentModule->getFunctionList().push_back(this); 181 182 // Ensure intrinsics have the right parameter attributes. 183 if (unsigned IID = getIntrinsicID()) 184 setAttributes(Intrinsic::getAttributes(Intrinsic::ID(IID))); 185 186 } 187 188 Function::~Function() { 189 dropAllReferences(); // After this it is safe to delete instructions. 190 191 // Delete all of the method arguments and unlink from symbol table... 192 ArgumentList.clear(); 193 delete SymTab; 194 195 // Remove the function from the on-the-side GC table. 196 clearGC(); 197 } 198 199 void Function::BuildLazyArguments() const { 200 // Create the arguments vector, all arguments start out unnamed. 201 FunctionType *FT = getFunctionType(); 202 for (unsigned i = 0, e = FT->getNumParams(); i != e; ++i) { 203 assert(!FT->getParamType(i)->isVoidTy() && 204 "Cannot have void typed arguments!"); 205 ArgumentList.push_back(new Argument(FT->getParamType(i))); 206 } 207 208 // Clear the lazy arguments bit. 209 unsigned SDC = getSubclassDataFromValue(); 210 const_cast<Function*>(this)->setValueSubclassData(SDC &= ~1); 211 } 212 213 size_t Function::arg_size() const { 214 return getFunctionType()->getNumParams(); 215 } 216 bool Function::arg_empty() const { 217 return getFunctionType()->getNumParams() == 0; 218 } 219 220 void Function::setParent(Module *parent) { 221 if (getParent()) 222 LeakDetector::addGarbageObject(this); 223 Parent = parent; 224 if (getParent()) 225 LeakDetector::removeGarbageObject(this); 226 } 227 228 // dropAllReferences() - This function causes all the subinstructions to "let 229 // go" of all references that they are maintaining. This allows one to 230 // 'delete' a whole class at a time, even though there may be circular 231 // references... first all references are dropped, and all use counts go to 232 // zero. Then everything is deleted for real. Note that no operations are 233 // valid on an object that has "dropped all references", except operator 234 // delete. 235 // 236 void Function::dropAllReferences() { 237 for (iterator I = begin(), E = end(); I != E; ++I) 238 I->dropAllReferences(); 239 240 // Delete all basic blocks. They are now unused, except possibly by 241 // blockaddresses, but BasicBlock's destructor takes care of those. 242 while (!BasicBlocks.empty()) 243 BasicBlocks.begin()->eraseFromParent(); 244 } 245 246 void Function::addAttribute(unsigned i, Attributes attr) { 247 AttrListPtr PAL = getAttributes(); 248 PAL = PAL.addAttr(i, attr); 249 setAttributes(PAL); 250 } 251 252 void Function::removeAttribute(unsigned i, Attributes attr) { 253 AttrListPtr PAL = getAttributes(); 254 PAL = PAL.removeAttr(i, attr); 255 setAttributes(PAL); 256 } 257 258 // Maintain the GC name for each function in an on-the-side table. This saves 259 // allocating an additional word in Function for programs which do not use GC 260 // (i.e., most programs) at the cost of increased overhead for clients which do 261 // use GC. 262 static DenseMap<const Function*,PooledStringPtr> *GCNames; 263 static StringPool *GCNamePool; 264 static ManagedStatic<sys::SmartRWMutex<true> > GCLock; 265 266 bool Function::hasGC() const { 267 sys::SmartScopedReader<true> Reader(*GCLock); 268 return GCNames && GCNames->count(this); 269 } 270 271 const char *Function::getGC() const { 272 assert(hasGC() && "Function has no collector"); 273 sys::SmartScopedReader<true> Reader(*GCLock); 274 return *(*GCNames)[this]; 275 } 276 277 void Function::setGC(const char *Str) { 278 sys::SmartScopedWriter<true> Writer(*GCLock); 279 if (!GCNamePool) 280 GCNamePool = new StringPool(); 281 if (!GCNames) 282 GCNames = new DenseMap<const Function*,PooledStringPtr>(); 283 (*GCNames)[this] = GCNamePool->intern(Str); 284 } 285 286 void Function::clearGC() { 287 sys::SmartScopedWriter<true> Writer(*GCLock); 288 if (GCNames) { 289 GCNames->erase(this); 290 if (GCNames->empty()) { 291 delete GCNames; 292 GCNames = 0; 293 if (GCNamePool->empty()) { 294 delete GCNamePool; 295 GCNamePool = 0; 296 } 297 } 298 } 299 } 300 301 /// copyAttributesFrom - copy all additional attributes (those not needed to 302 /// create a Function) from the Function Src to this one. 303 void Function::copyAttributesFrom(const GlobalValue *Src) { 304 assert(isa<Function>(Src) && "Expected a Function!"); 305 GlobalValue::copyAttributesFrom(Src); 306 const Function *SrcF = cast<Function>(Src); 307 setCallingConv(SrcF->getCallingConv()); 308 setAttributes(SrcF->getAttributes()); 309 if (SrcF->hasGC()) 310 setGC(SrcF->getGC()); 311 else 312 clearGC(); 313 } 314 315 /// getIntrinsicID - This method returns the ID number of the specified 316 /// function, or Intrinsic::not_intrinsic if the function is not an 317 /// intrinsic, or if the pointer is null. This value is always defined to be 318 /// zero to allow easy checking for whether a function is intrinsic or not. The 319 /// particular intrinsic functions which correspond to this value are defined in 320 /// llvm/Intrinsics.h. 321 /// 322 unsigned Function::getIntrinsicID() const { 323 const ValueName *ValName = this->getValueName(); 324 if (!ValName) 325 return 0; 326 unsigned Len = ValName->getKeyLength(); 327 const char *Name = ValName->getKeyData(); 328 329 if (Len < 5 || Name[4] != '.' || Name[0] != 'l' || Name[1] != 'l' 330 || Name[2] != 'v' || Name[3] != 'm') 331 return 0; // All intrinsics start with 'llvm.' 332 333 #define GET_FUNCTION_RECOGNIZER 334 #include "llvm/Intrinsics.gen" 335 #undef GET_FUNCTION_RECOGNIZER 336 return 0; 337 } 338 339 std::string Intrinsic::getName(ID id, ArrayRef<Type*> Tys) { 340 assert(id < num_intrinsics && "Invalid intrinsic ID!"); 341 static const char * const Table[] = { 342 "not_intrinsic", 343 #define GET_INTRINSIC_NAME_TABLE 344 #include "llvm/Intrinsics.gen" 345 #undef GET_INTRINSIC_NAME_TABLE 346 }; 347 if (Tys.empty()) 348 return Table[id]; 349 std::string Result(Table[id]); 350 for (unsigned i = 0; i < Tys.size(); ++i) { 351 if (PointerType* PTyp = dyn_cast<PointerType>(Tys[i])) { 352 Result += ".p" + llvm::utostr(PTyp->getAddressSpace()) + 353 EVT::getEVT(PTyp->getElementType()).getEVTString(); 354 } 355 else if (Tys[i]) 356 Result += "." + EVT::getEVT(Tys[i]).getEVTString(); 357 } 358 return Result; 359 } 360 361 FunctionType *Intrinsic::getType(LLVMContext &Context, 362 ID id, ArrayRef<Type*> Tys) { 363 Type *ResultTy = NULL; 364 SmallVector<Type*, 8> ArgTys; 365 bool IsVarArg = false; 366 367 #define GET_INTRINSIC_GENERATOR 368 #include "llvm/Intrinsics.gen" 369 #undef GET_INTRINSIC_GENERATOR 370 371 return FunctionType::get(ResultTy, ArgTys, IsVarArg); 372 } 373 374 bool Intrinsic::isOverloaded(ID id) { 375 #define GET_INTRINSIC_OVERLOAD_TABLE 376 #include "llvm/Intrinsics.gen" 377 #undef GET_INTRINSIC_OVERLOAD_TABLE 378 } 379 380 /// This defines the "Intrinsic::getAttributes(ID id)" method. 381 #define GET_INTRINSIC_ATTRIBUTES 382 #include "llvm/Intrinsics.gen" 383 #undef GET_INTRINSIC_ATTRIBUTES 384 385 Function *Intrinsic::getDeclaration(Module *M, ID id, ArrayRef<Type*> Tys) { 386 // There can never be multiple globals with the same name of different types, 387 // because intrinsics must be a specific type. 388 return 389 cast<Function>(M->getOrInsertFunction(getName(id, Tys), 390 getType(M->getContext(), id, Tys))); 391 } 392 393 // This defines the "Intrinsic::getIntrinsicForGCCBuiltin()" method. 394 #define GET_LLVM_INTRINSIC_FOR_GCC_BUILTIN 395 #include "llvm/Intrinsics.gen" 396 #undef GET_LLVM_INTRINSIC_FOR_GCC_BUILTIN 397 398 /// hasAddressTaken - returns true if there are any uses of this function 399 /// other than direct calls or invokes to it. 400 bool Function::hasAddressTaken(const User* *PutOffender) const { 401 for (Value::const_use_iterator I = use_begin(), E = use_end(); I != E; ++I) { 402 const User *U = *I; 403 // FIXME: Check for blockaddress, which does not take the address. 404 if (!isa<CallInst>(U) && !isa<InvokeInst>(U)) 405 return PutOffender ? (*PutOffender = U, true) : true; 406 ImmutableCallSite CS(cast<Instruction>(U)); 407 if (!CS.isCallee(I)) 408 return PutOffender ? (*PutOffender = U, true) : true; 409 } 410 return false; 411 } 412 413 bool Function::isDefTriviallyDead() const { 414 // Check the linkage 415 if (!hasLinkOnceLinkage() && !hasLocalLinkage() && 416 !hasAvailableExternallyLinkage()) 417 return false; 418 419 // Check if the function is used by anything other than a blockaddress. 420 for (Value::const_use_iterator I = use_begin(), E = use_end(); I != E; ++I) 421 if (!isa<BlockAddress>(*I)) 422 return false; 423 424 return true; 425 } 426 427 /// callsFunctionThatReturnsTwice - Return true if the function has a call to 428 /// setjmp or other function that gcc recognizes as "returning twice". 429 bool Function::callsFunctionThatReturnsTwice() const { 430 for (const_inst_iterator 431 I = inst_begin(this), E = inst_end(this); I != E; ++I) { 432 const CallInst* callInst = dyn_cast<CallInst>(&*I); 433 if (!callInst) 434 continue; 435 if (callInst->canReturnTwice()) 436 return true; 437 } 438 439 return false; 440 } 441 442 // vim: sw=2 ai 443