1 //===-- Globals.cpp - Implement the GlobalValue & GlobalVariable class ----===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file implements the GlobalValue & GlobalVariable classes for the IR
13 //===----------------------------------------------------------------------===//
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/Module.h"
22 #include "llvm/IR/Operator.h"
23 #include "llvm/Support/ErrorHandling.h"
26 //===----------------------------------------------------------------------===//
28 //===----------------------------------------------------------------------===//
30 bool GlobalValue::isMaterializable() const {
31 if (const Function *F = dyn_cast<Function>(this))
32 return F->isMaterializable();
35 bool GlobalValue::isDematerializable() const {
36 return getParent() && getParent()->isDematerializable(this);
38 std::error_code GlobalValue::materialize() {
39 return getParent()->materialize(this);
41 void GlobalValue::dematerialize() {
42 getParent()->dematerialize(this);
45 /// Override destroyConstantImpl to make sure it doesn't get called on
46 /// GlobalValue's because they shouldn't be treated like other constants.
47 void GlobalValue::destroyConstantImpl() {
48 llvm_unreachable("You can't GV->destroyConstantImpl()!");
51 Value *GlobalValue::handleOperandChangeImpl(Value *From, Value *To, Use *U) {
52 llvm_unreachable("Unsupported class for handleOperandChange()!");
55 /// copyAttributesFrom - copy all additional attributes (those not needed to
56 /// create a GlobalValue) from the GlobalValue Src to this one.
57 void GlobalValue::copyAttributesFrom(const GlobalValue *Src) {
58 setVisibility(Src->getVisibility());
59 setUnnamedAddr(Src->hasUnnamedAddr());
60 setDLLStorageClass(Src->getDLLStorageClass());
63 unsigned GlobalValue::getAlignment() const {
64 if (auto *GA = dyn_cast<GlobalAlias>(this)) {
65 // In general we cannot compute this at the IR level, but we try.
66 if (const GlobalObject *GO = GA->getBaseObject())
67 return GO->getAlignment();
69 // FIXME: we should also be able to handle:
70 // Alias = Global + Offset
74 return cast<GlobalObject>(this)->getAlignment();
77 void GlobalObject::setAlignment(unsigned Align) {
78 assert((Align & (Align-1)) == 0 && "Alignment is not a power of 2!");
79 assert(Align <= MaximumAlignment &&
80 "Alignment is greater than MaximumAlignment!");
81 unsigned AlignmentData = Log2_32(Align) + 1;
82 unsigned OldData = getGlobalValueSubClassData();
83 setGlobalValueSubClassData((OldData & ~AlignmentMask) | AlignmentData);
84 assert(getAlignment() == Align && "Alignment representation error!");
87 unsigned GlobalObject::getGlobalObjectSubClassData() const {
88 unsigned ValueData = getGlobalValueSubClassData();
89 return ValueData >> AlignmentBits;
92 void GlobalObject::setGlobalObjectSubClassData(unsigned Val) {
93 unsigned OldData = getGlobalValueSubClassData();
94 setGlobalValueSubClassData((OldData & AlignmentMask) |
95 (Val << AlignmentBits));
96 assert(getGlobalObjectSubClassData() == Val && "representation error");
99 void GlobalObject::copyAttributesFrom(const GlobalValue *Src) {
100 const auto *GV = cast<GlobalObject>(Src);
101 GlobalValue::copyAttributesFrom(GV);
102 setAlignment(GV->getAlignment());
103 setSection(GV->getSection());
106 const char *GlobalValue::getSection() const {
107 if (auto *GA = dyn_cast<GlobalAlias>(this)) {
108 // In general we cannot compute this at the IR level, but we try.
109 if (const GlobalObject *GO = GA->getBaseObject())
110 return GO->getSection();
113 return cast<GlobalObject>(this)->getSection();
116 Comdat *GlobalValue::getComdat() {
117 if (auto *GA = dyn_cast<GlobalAlias>(this)) {
118 // In general we cannot compute this at the IR level, but we try.
119 if (const GlobalObject *GO = GA->getBaseObject())
120 return const_cast<GlobalObject *>(GO)->getComdat();
123 return cast<GlobalObject>(this)->getComdat();
126 void GlobalObject::setSection(StringRef S) { Section = S; }
128 bool GlobalValue::isDeclaration() const {
129 // Globals are definitions if they have an initializer.
130 if (const GlobalVariable *GV = dyn_cast<GlobalVariable>(this))
131 return GV->getNumOperands() == 0;
133 // Functions are definitions if they have a body.
134 if (const Function *F = dyn_cast<Function>(this))
135 return F->empty() && !F->isMaterializable();
137 // Aliases are always definitions.
138 assert(isa<GlobalAlias>(this));
142 //===----------------------------------------------------------------------===//
143 // GlobalVariable Implementation
144 //===----------------------------------------------------------------------===//
146 GlobalVariable::GlobalVariable(Type *Ty, bool constant, LinkageTypes Link,
147 Constant *InitVal, const Twine &Name,
148 ThreadLocalMode TLMode, unsigned AddressSpace,
149 bool isExternallyInitialized)
150 : GlobalObject(Ty, Value::GlobalVariableVal,
151 OperandTraits<GlobalVariable>::op_begin(this),
152 InitVal != nullptr, Link, Name, AddressSpace),
153 isConstantGlobal(constant),
154 isExternallyInitializedConstant(isExternallyInitialized) {
155 setThreadLocalMode(TLMode);
157 assert(InitVal->getType() == Ty &&
158 "Initializer should be the same type as the GlobalVariable!");
163 GlobalVariable::GlobalVariable(Module &M, Type *Ty, bool constant,
164 LinkageTypes Link, Constant *InitVal,
165 const Twine &Name, GlobalVariable *Before,
166 ThreadLocalMode TLMode, unsigned AddressSpace,
167 bool isExternallyInitialized)
168 : GlobalObject(Ty, Value::GlobalVariableVal,
169 OperandTraits<GlobalVariable>::op_begin(this),
170 InitVal != nullptr, Link, Name, AddressSpace),
171 isConstantGlobal(constant),
172 isExternallyInitializedConstant(isExternallyInitialized) {
173 setThreadLocalMode(TLMode);
175 assert(InitVal->getType() == Ty &&
176 "Initializer should be the same type as the GlobalVariable!");
181 Before->getParent()->getGlobalList().insert(Before, this);
183 M.getGlobalList().push_back(this);
186 void GlobalVariable::setParent(Module *parent) {
190 void GlobalVariable::removeFromParent() {
191 getParent()->getGlobalList().remove(this);
194 void GlobalVariable::eraseFromParent() {
195 getParent()->getGlobalList().erase(this);
198 void GlobalVariable::setInitializer(Constant *InitVal) {
200 if (hasInitializer()) {
201 // Note, the num operands is used to compute the offset of the operand, so
202 // the order here matters. Clearing the operand then clearing the num
203 // operands ensures we have the correct offset to the operand.
204 Op<0>().set(nullptr);
205 setGlobalVariableNumOperands(0);
208 assert(InitVal->getType() == getType()->getElementType() &&
209 "Initializer type must match GlobalVariable type");
210 // Note, the num operands is used to compute the offset of the operand, so
211 // the order here matters. We need to set num operands to 1 first so that
212 // we get the correct offset to the first operand when we set it.
213 if (!hasInitializer())
214 setGlobalVariableNumOperands(1);
215 Op<0>().set(InitVal);
219 /// copyAttributesFrom - copy all additional attributes (those not needed to
220 /// create a GlobalVariable) from the GlobalVariable Src to this one.
221 void GlobalVariable::copyAttributesFrom(const GlobalValue *Src) {
222 assert(isa<GlobalVariable>(Src) && "Expected a GlobalVariable!");
223 GlobalObject::copyAttributesFrom(Src);
224 const GlobalVariable *SrcVar = cast<GlobalVariable>(Src);
225 setThreadLocalMode(SrcVar->getThreadLocalMode());
226 setExternallyInitialized(SrcVar->isExternallyInitialized());
230 //===----------------------------------------------------------------------===//
231 // GlobalAlias Implementation
232 //===----------------------------------------------------------------------===//
234 GlobalAlias::GlobalAlias(Type *Ty, unsigned AddressSpace, LinkageTypes Link,
235 const Twine &Name, Constant *Aliasee,
236 Module *ParentModule)
237 : GlobalValue(Ty, Value::GlobalAliasVal, &Op<0>(), 1, Link, Name,
242 ParentModule->getAliasList().push_back(this);
245 GlobalAlias *GlobalAlias::create(Type *Ty, unsigned AddressSpace,
246 LinkageTypes Link, const Twine &Name,
247 Constant *Aliasee, Module *ParentModule) {
248 return new GlobalAlias(Ty, AddressSpace, Link, Name, Aliasee, ParentModule);
251 GlobalAlias *GlobalAlias::create(Type *Ty, unsigned AddressSpace,
252 LinkageTypes Linkage, const Twine &Name,
254 return create(Ty, AddressSpace, Linkage, Name, nullptr, Parent);
257 GlobalAlias *GlobalAlias::create(Type *Ty, unsigned AddressSpace,
258 LinkageTypes Linkage, const Twine &Name,
259 GlobalValue *Aliasee) {
260 return create(Ty, AddressSpace, Linkage, Name, Aliasee, Aliasee->getParent());
263 GlobalAlias *GlobalAlias::create(LinkageTypes Link, const Twine &Name,
264 GlobalValue *Aliasee) {
265 PointerType *PTy = Aliasee->getType();
266 return create(PTy->getElementType(), PTy->getAddressSpace(), Link, Name,
270 GlobalAlias *GlobalAlias::create(const Twine &Name, GlobalValue *Aliasee) {
271 return create(Aliasee->getLinkage(), Name, Aliasee);
274 void GlobalAlias::setParent(Module *parent) {
278 void GlobalAlias::removeFromParent() {
279 getParent()->getAliasList().remove(this);
282 void GlobalAlias::eraseFromParent() {
283 getParent()->getAliasList().erase(this);
286 void GlobalAlias::setAliasee(Constant *Aliasee) {
287 assert((!Aliasee || Aliasee->getType() == getType()) &&
288 "Alias and aliasee types should match!");
289 setOperand(0, Aliasee);