1 //===-- Globals.cpp - Implement the GlobalValue & GlobalVariable 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 GlobalValue & GlobalVariable classes for the IR 11 // library. 12 // 13 //===----------------------------------------------------------------------===// 14 15 #include "llvm/IR/GlobalValue.h" 16 #include "llvm/ADT/SmallPtrSet.h" 17 #include "llvm/IR/Constants.h" 18 #include "llvm/IR/DerivedTypes.h" 19 #include "llvm/IR/GlobalAlias.h" 20 #include "llvm/IR/GlobalVariable.h" 21 #include "llvm/IR/LeakDetector.h" 22 #include "llvm/IR/Module.h" 23 #include "llvm/IR/Operator.h" 24 #include "llvm/Support/ErrorHandling.h" 25 using namespace llvm; 26 27 //===----------------------------------------------------------------------===// 28 // GlobalValue Class 29 //===----------------------------------------------------------------------===// 30 31 bool GlobalValue::isMaterializable() const { 32 return getParent() && getParent()->isMaterializable(this); 33 } 34 bool GlobalValue::isDematerializable() const { 35 return getParent() && getParent()->isDematerializable(this); 36 } 37 bool GlobalValue::Materialize(std::string *ErrInfo) { 38 return getParent()->Materialize(this, ErrInfo); 39 } 40 void GlobalValue::Dematerialize() { 41 getParent()->Dematerialize(this); 42 } 43 44 const DataLayout *GlobalValue::getDataLayout() const { 45 return getParent()->getDataLayout(); 46 } 47 48 /// Override destroyConstant to make sure it doesn't get called on 49 /// GlobalValue's because they shouldn't be treated like other constants. 50 void GlobalValue::destroyConstant() { 51 llvm_unreachable("You can't GV->destroyConstant()!"); 52 } 53 54 /// copyAttributesFrom - copy all additional attributes (those not needed to 55 /// create a GlobalValue) from the GlobalValue Src to this one. 56 void GlobalValue::copyAttributesFrom(const GlobalValue *Src) { 57 setVisibility(Src->getVisibility()); 58 setUnnamedAddr(Src->hasUnnamedAddr()); 59 setDLLStorageClass(Src->getDLLStorageClass()); 60 } 61 62 unsigned GlobalValue::getAlignment() const { 63 if (auto *GA = dyn_cast<GlobalAlias>(this)) { 64 // In general we cannot compute this at the IR level, but we try. 65 if (const GlobalObject *GO = GA->getBaseObject()) 66 return GO->getAlignment(); 67 68 // FIXME: we should also be able to handle: 69 // Alias = Global + Offset 70 // Alias = Absolute 71 return 0; 72 } 73 return cast<GlobalObject>(this)->getAlignment(); 74 } 75 76 void GlobalObject::setAlignment(unsigned Align) { 77 assert((Align & (Align-1)) == 0 && "Alignment is not a power of 2!"); 78 assert(Align <= MaximumAlignment && 79 "Alignment is greater than MaximumAlignment!"); 80 setGlobalValueSubClassData(Log2_32(Align) + 1); 81 assert(getAlignment() == Align && "Alignment representation error!"); 82 } 83 84 void GlobalObject::copyAttributesFrom(const GlobalValue *Src) { 85 const auto *GV = cast<GlobalObject>(Src); 86 GlobalValue::copyAttributesFrom(GV); 87 setAlignment(GV->getAlignment()); 88 setSection(GV->getSection()); 89 } 90 91 const char *GlobalValue::getSection() const { 92 if (auto *GA = dyn_cast<GlobalAlias>(this)) { 93 // In general we cannot compute this at the IR level, but we try. 94 if (const GlobalObject *GO = GA->getBaseObject()) 95 return GO->getSection(); 96 return ""; 97 } 98 return cast<GlobalObject>(this)->getSection(); 99 } 100 101 Comdat *GlobalValue::getComdat() { 102 if (auto *GA = dyn_cast<GlobalAlias>(this)) { 103 // In general we cannot compute this at the IR level, but we try. 104 if (const GlobalObject *GO = GA->getBaseObject()) 105 return const_cast<GlobalObject *>(GO)->getComdat(); 106 return nullptr; 107 } 108 return cast<GlobalObject>(this)->getComdat(); 109 } 110 111 void GlobalObject::setSection(StringRef S) { Section = S; } 112 113 bool GlobalValue::isDeclaration() const { 114 // Globals are definitions if they have an initializer. 115 if (const GlobalVariable *GV = dyn_cast<GlobalVariable>(this)) 116 return GV->getNumOperands() == 0; 117 118 // Functions are definitions if they have a body. 119 if (const Function *F = dyn_cast<Function>(this)) 120 return F->empty(); 121 122 // Aliases are always definitions. 123 assert(isa<GlobalAlias>(this)); 124 return false; 125 } 126 127 //===----------------------------------------------------------------------===// 128 // GlobalVariable Implementation 129 //===----------------------------------------------------------------------===// 130 131 GlobalVariable::GlobalVariable(Type *Ty, bool constant, LinkageTypes Link, 132 Constant *InitVal, const Twine &Name, 133 ThreadLocalMode TLMode, unsigned AddressSpace, 134 bool isExternallyInitialized) 135 : GlobalObject(PointerType::get(Ty, AddressSpace), Value::GlobalVariableVal, 136 OperandTraits<GlobalVariable>::op_begin(this), 137 InitVal != nullptr, Link, Name), 138 isConstantGlobal(constant), 139 isExternallyInitializedConstant(isExternallyInitialized) { 140 setThreadLocalMode(TLMode); 141 if (InitVal) { 142 assert(InitVal->getType() == Ty && 143 "Initializer should be the same type as the GlobalVariable!"); 144 Op<0>() = InitVal; 145 } 146 147 LeakDetector::addGarbageObject(this); 148 } 149 150 GlobalVariable::GlobalVariable(Module &M, Type *Ty, bool constant, 151 LinkageTypes Link, Constant *InitVal, 152 const Twine &Name, GlobalVariable *Before, 153 ThreadLocalMode TLMode, unsigned AddressSpace, 154 bool isExternallyInitialized) 155 : GlobalObject(PointerType::get(Ty, AddressSpace), Value::GlobalVariableVal, 156 OperandTraits<GlobalVariable>::op_begin(this), 157 InitVal != nullptr, Link, Name), 158 isConstantGlobal(constant), 159 isExternallyInitializedConstant(isExternallyInitialized) { 160 setThreadLocalMode(TLMode); 161 if (InitVal) { 162 assert(InitVal->getType() == Ty && 163 "Initializer should be the same type as the GlobalVariable!"); 164 Op<0>() = InitVal; 165 } 166 167 LeakDetector::addGarbageObject(this); 168 169 if (Before) 170 Before->getParent()->getGlobalList().insert(Before, this); 171 else 172 M.getGlobalList().push_back(this); 173 } 174 175 void GlobalVariable::setParent(Module *parent) { 176 if (getParent()) 177 LeakDetector::addGarbageObject(this); 178 Parent = parent; 179 if (getParent()) 180 LeakDetector::removeGarbageObject(this); 181 } 182 183 void GlobalVariable::removeFromParent() { 184 getParent()->getGlobalList().remove(this); 185 } 186 187 void GlobalVariable::eraseFromParent() { 188 getParent()->getGlobalList().erase(this); 189 } 190 191 void GlobalVariable::replaceUsesOfWithOnConstant(Value *From, Value *To, 192 Use *U) { 193 // If you call this, then you better know this GVar has a constant 194 // initializer worth replacing. Enforce that here. 195 assert(getNumOperands() == 1 && 196 "Attempt to replace uses of Constants on a GVar with no initializer"); 197 198 // And, since you know it has an initializer, the From value better be 199 // the initializer :) 200 assert(getOperand(0) == From && 201 "Attempt to replace wrong constant initializer in GVar"); 202 203 // And, you better have a constant for the replacement value 204 assert(isa<Constant>(To) && 205 "Attempt to replace GVar initializer with non-constant"); 206 207 // Okay, preconditions out of the way, replace the constant initializer. 208 this->setOperand(0, cast<Constant>(To)); 209 } 210 211 void GlobalVariable::setInitializer(Constant *InitVal) { 212 if (!InitVal) { 213 if (hasInitializer()) { 214 Op<0>().set(nullptr); 215 NumOperands = 0; 216 } 217 } else { 218 assert(InitVal->getType() == getType()->getElementType() && 219 "Initializer type must match GlobalVariable type"); 220 if (!hasInitializer()) 221 NumOperands = 1; 222 Op<0>().set(InitVal); 223 } 224 } 225 226 /// copyAttributesFrom - copy all additional attributes (those not needed to 227 /// create a GlobalVariable) from the GlobalVariable Src to this one. 228 void GlobalVariable::copyAttributesFrom(const GlobalValue *Src) { 229 assert(isa<GlobalVariable>(Src) && "Expected a GlobalVariable!"); 230 GlobalObject::copyAttributesFrom(Src); 231 const GlobalVariable *SrcVar = cast<GlobalVariable>(Src); 232 setThreadLocalMode(SrcVar->getThreadLocalMode()); 233 } 234 235 236 //===----------------------------------------------------------------------===// 237 // GlobalAlias Implementation 238 //===----------------------------------------------------------------------===// 239 240 GlobalAlias::GlobalAlias(Type *Ty, unsigned AddressSpace, LinkageTypes Link, 241 const Twine &Name, Constant *Aliasee, 242 Module *ParentModule) 243 : GlobalValue(PointerType::get(Ty, AddressSpace), Value::GlobalAliasVal, 244 &Op<0>(), 1, Link, Name) { 245 LeakDetector::addGarbageObject(this); 246 Op<0>() = Aliasee; 247 248 if (ParentModule) 249 ParentModule->getAliasList().push_back(this); 250 } 251 252 GlobalAlias *GlobalAlias::create(Type *Ty, unsigned AddressSpace, 253 LinkageTypes Link, const Twine &Name, 254 Constant *Aliasee, Module *ParentModule) { 255 return new GlobalAlias(Ty, AddressSpace, Link, Name, Aliasee, ParentModule); 256 } 257 258 GlobalAlias *GlobalAlias::create(Type *Ty, unsigned AddressSpace, 259 LinkageTypes Linkage, const Twine &Name, 260 Module *Parent) { 261 return create(Ty, AddressSpace, Linkage, Name, nullptr, Parent); 262 } 263 264 GlobalAlias *GlobalAlias::create(Type *Ty, unsigned AddressSpace, 265 LinkageTypes Linkage, const Twine &Name, 266 GlobalValue *Aliasee) { 267 return create(Ty, AddressSpace, Linkage, Name, Aliasee, Aliasee->getParent()); 268 } 269 270 GlobalAlias *GlobalAlias::create(LinkageTypes Link, const Twine &Name, 271 GlobalValue *Aliasee) { 272 PointerType *PTy = Aliasee->getType(); 273 return create(PTy->getElementType(), PTy->getAddressSpace(), Link, Name, 274 Aliasee); 275 } 276 277 GlobalAlias *GlobalAlias::create(const Twine &Name, GlobalValue *Aliasee) { 278 return create(Aliasee->getLinkage(), Name, Aliasee); 279 } 280 281 void GlobalAlias::setParent(Module *parent) { 282 if (getParent()) 283 LeakDetector::addGarbageObject(this); 284 Parent = parent; 285 if (getParent()) 286 LeakDetector::removeGarbageObject(this); 287 } 288 289 void GlobalAlias::removeFromParent() { 290 getParent()->getAliasList().remove(this); 291 } 292 293 void GlobalAlias::eraseFromParent() { 294 getParent()->getAliasList().erase(this); 295 } 296 297 void GlobalAlias::setAliasee(Constant *Aliasee) { 298 assert((!Aliasee || Aliasee->getType() == getType()) && 299 "Alias and aliasee types should match!"); 300 setOperand(0, Aliasee); 301 } 302
