//===-- Globals.cpp - Implement the GlobalValue & GlobalVariable class ----===// // // The LLVM Compiler Infrastructure // // This file is distributed under the University of Illinois Open Source // License. See LICENSE.TXT for details. // //===----------------------------------------------------------------------===// // // This file implements the GlobalValue & GlobalVariable classes for the IR // library. // //===----------------------------------------------------------------------===// #include "llvm/IR/GlobalValue.h" #include "llvm/ADT/SmallPtrSet.h" #include "llvm/IR/Constants.h" #include "llvm/IR/DerivedTypes.h" #include "llvm/IR/GlobalAlias.h" #include "llvm/IR/GlobalVariable.h" #include "llvm/IR/Module.h" #include "llvm/IR/Operator.h" #include "llvm/Support/ErrorHandling.h" using namespace llvm; //===----------------------------------------------------------------------===// // GlobalValue Class //===----------------------------------------------------------------------===// bool GlobalValue::isMaterializable() const { if (const Function *F = dyn_cast<Function>(this)) return F->isMaterializable(); return false; } bool GlobalValue::isDematerializable() const { return getParent() && getParent()->isDematerializable(this); } std::error_code GlobalValue::materialize() { return getParent()->materialize(this); } void GlobalValue::Dematerialize() { getParent()->Dematerialize(this); } const DataLayout *GlobalValue::getDataLayout() const { return getParent()->getDataLayout(); } /// Override destroyConstant to make sure it doesn't get called on /// GlobalValue's because they shouldn't be treated like other constants. void GlobalValue::destroyConstant() { llvm_unreachable("You can't GV->destroyConstant()!"); } /// copyAttributesFrom - copy all additional attributes (those not needed to /// create a GlobalValue) from the GlobalValue Src to this one. void GlobalValue::copyAttributesFrom(const GlobalValue *Src) { setVisibility(Src->getVisibility()); setUnnamedAddr(Src->hasUnnamedAddr()); setDLLStorageClass(Src->getDLLStorageClass()); } unsigned GlobalValue::getAlignment() const { if (auto *GA = dyn_cast<GlobalAlias>(this)) { // In general we cannot compute this at the IR level, but we try. if (const GlobalObject *GO = GA->getBaseObject()) return GO->getAlignment(); // FIXME: we should also be able to handle: // Alias = Global + Offset // Alias = Absolute return 0; } return cast<GlobalObject>(this)->getAlignment(); } void GlobalObject::setAlignment(unsigned Align) { assert((Align & (Align-1)) == 0 && "Alignment is not a power of 2!"); assert(Align <= MaximumAlignment && "Alignment is greater than MaximumAlignment!"); unsigned AlignmentData = Log2_32(Align) + 1; unsigned OldData = getGlobalValueSubClassData(); setGlobalValueSubClassData((OldData & ~AlignmentMask) | AlignmentData); assert(getAlignment() == Align && "Alignment representation error!"); } unsigned GlobalObject::getGlobalObjectSubClassData() const { unsigned ValueData = getGlobalValueSubClassData(); return ValueData >> AlignmentBits; } void GlobalObject::setGlobalObjectSubClassData(unsigned Val) { unsigned OldData = getGlobalValueSubClassData(); setGlobalValueSubClassData((OldData & AlignmentMask) | (Val << AlignmentBits)); assert(getGlobalObjectSubClassData() == Val && "representation error"); } void GlobalObject::copyAttributesFrom(const GlobalValue *Src) { const auto *GV = cast<GlobalObject>(Src); GlobalValue::copyAttributesFrom(GV); setAlignment(GV->getAlignment()); setSection(GV->getSection()); } const char *GlobalValue::getSection() const { if (auto *GA = dyn_cast<GlobalAlias>(this)) { // In general we cannot compute this at the IR level, but we try. if (const GlobalObject *GO = GA->getBaseObject()) return GO->getSection(); return ""; } return cast<GlobalObject>(this)->getSection(); } Comdat *GlobalValue::getComdat() { if (auto *GA = dyn_cast<GlobalAlias>(this)) { // In general we cannot compute this at the IR level, but we try. if (const GlobalObject *GO = GA->getBaseObject()) return const_cast<GlobalObject *>(GO)->getComdat(); return nullptr; } return cast<GlobalObject>(this)->getComdat(); } void GlobalObject::setSection(StringRef S) { Section = S; } bool GlobalValue::isDeclaration() const { // Globals are definitions if they have an initializer. if (const GlobalVariable *GV = dyn_cast<GlobalVariable>(this)) return GV->getNumOperands() == 0; // Functions are definitions if they have a body. if (const Function *F = dyn_cast<Function>(this)) return F->empty() && !F->isMaterializable(); // Aliases are always definitions. assert(isa<GlobalAlias>(this)); return false; } //===----------------------------------------------------------------------===// // GlobalVariable Implementation //===----------------------------------------------------------------------===// GlobalVariable::GlobalVariable(Type *Ty, bool constant, LinkageTypes Link, Constant *InitVal, const Twine &Name, ThreadLocalMode TLMode, unsigned AddressSpace, bool isExternallyInitialized) : GlobalObject(PointerType::get(Ty, AddressSpace), Value::GlobalVariableVal, OperandTraits<GlobalVariable>::op_begin(this), InitVal != nullptr, Link, Name), isConstantGlobal(constant), isExternallyInitializedConstant(isExternallyInitialized) { setThreadLocalMode(TLMode); if (InitVal) { assert(InitVal->getType() == Ty && "Initializer should be the same type as the GlobalVariable!"); Op<0>() = InitVal; } } GlobalVariable::GlobalVariable(Module &M, Type *Ty, bool constant, LinkageTypes Link, Constant *InitVal, const Twine &Name, GlobalVariable *Before, ThreadLocalMode TLMode, unsigned AddressSpace, bool isExternallyInitialized) : GlobalObject(PointerType::get(Ty, AddressSpace), Value::GlobalVariableVal, OperandTraits<GlobalVariable>::op_begin(this), InitVal != nullptr, Link, Name), isConstantGlobal(constant), isExternallyInitializedConstant(isExternallyInitialized) { setThreadLocalMode(TLMode); if (InitVal) { assert(InitVal->getType() == Ty && "Initializer should be the same type as the GlobalVariable!"); Op<0>() = InitVal; } if (Before) Before->getParent()->getGlobalList().insert(Before, this); else M.getGlobalList().push_back(this); } void GlobalVariable::setParent(Module *parent) { Parent = parent; } void GlobalVariable::removeFromParent() { getParent()->getGlobalList().remove(this); } void GlobalVariable::eraseFromParent() { getParent()->getGlobalList().erase(this); } void GlobalVariable::replaceUsesOfWithOnConstant(Value *From, Value *To, Use *U) { // If you call this, then you better know this GVar has a constant // initializer worth replacing. Enforce that here. assert(getNumOperands() == 1 && "Attempt to replace uses of Constants on a GVar with no initializer"); // And, since you know it has an initializer, the From value better be // the initializer :) assert(getOperand(0) == From && "Attempt to replace wrong constant initializer in GVar"); // And, you better have a constant for the replacement value assert(isa<Constant>(To) && "Attempt to replace GVar initializer with non-constant"); // Okay, preconditions out of the way, replace the constant initializer. this->setOperand(0, cast<Constant>(To)); } void GlobalVariable::setInitializer(Constant *InitVal) { if (!InitVal) { if (hasInitializer()) { Op<0>().set(nullptr); NumOperands = 0; } } else { assert(InitVal->getType() == getType()->getElementType() && "Initializer type must match GlobalVariable type"); if (!hasInitializer()) NumOperands = 1; Op<0>().set(InitVal); } } /// copyAttributesFrom - copy all additional attributes (those not needed to /// create a GlobalVariable) from the GlobalVariable Src to this one. void GlobalVariable::copyAttributesFrom(const GlobalValue *Src) { assert(isa<GlobalVariable>(Src) && "Expected a GlobalVariable!"); GlobalObject::copyAttributesFrom(Src); const GlobalVariable *SrcVar = cast<GlobalVariable>(Src); setThreadLocalMode(SrcVar->getThreadLocalMode()); setExternallyInitialized(SrcVar->isExternallyInitialized()); } //===----------------------------------------------------------------------===// // GlobalAlias Implementation //===----------------------------------------------------------------------===// GlobalAlias::GlobalAlias(Type *Ty, unsigned AddressSpace, LinkageTypes Link, const Twine &Name, Constant *Aliasee, Module *ParentModule) : GlobalValue(PointerType::get(Ty, AddressSpace), Value::GlobalAliasVal, &Op<0>(), 1, Link, Name) { Op<0>() = Aliasee; if (ParentModule) ParentModule->getAliasList().push_back(this); } GlobalAlias *GlobalAlias::create(Type *Ty, unsigned AddressSpace, LinkageTypes Link, const Twine &Name, Constant *Aliasee, Module *ParentModule) { return new GlobalAlias(Ty, AddressSpace, Link, Name, Aliasee, ParentModule); } GlobalAlias *GlobalAlias::create(Type *Ty, unsigned AddressSpace, LinkageTypes Linkage, const Twine &Name, Module *Parent) { return create(Ty, AddressSpace, Linkage, Name, nullptr, Parent); } GlobalAlias *GlobalAlias::create(Type *Ty, unsigned AddressSpace, LinkageTypes Linkage, const Twine &Name, GlobalValue *Aliasee) { return create(Ty, AddressSpace, Linkage, Name, Aliasee, Aliasee->getParent()); } GlobalAlias *GlobalAlias::create(LinkageTypes Link, const Twine &Name, GlobalValue *Aliasee) { PointerType *PTy = Aliasee->getType(); return create(PTy->getElementType(), PTy->getAddressSpace(), Link, Name, Aliasee); } GlobalAlias *GlobalAlias::create(const Twine &Name, GlobalValue *Aliasee) { return create(Aliasee->getLinkage(), Name, Aliasee); } void GlobalAlias::setParent(Module *parent) { Parent = parent; } void GlobalAlias::removeFromParent() { getParent()->getAliasList().remove(this); } void GlobalAlias::eraseFromParent() { getParent()->getAliasList().erase(this); } void GlobalAlias::setAliasee(Constant *Aliasee) { assert((!Aliasee || Aliasee->getType() == getType()) && "Alias and aliasee types should match!"); setOperand(0, Aliasee); }