| //===-- 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 VMCore |
| // library. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #include "llvm/Constants.h" |
| #include "llvm/GlobalVariable.h" |
| #include "llvm/GlobalAlias.h" |
| #include "llvm/DerivedTypes.h" |
| #include "llvm/LLVMContext.h" |
| #include "llvm/Module.h" |
| #include "llvm/ADT/SmallPtrSet.h" |
| #include "llvm/Support/ErrorHandling.h" |
| #include "llvm/Support/LeakDetector.h" |
| #include "llvm/Support/Streams.h" |
| using namespace llvm; |
| |
| //===----------------------------------------------------------------------===// |
| // GlobalValue Class |
| //===----------------------------------------------------------------------===// |
| |
| /// removeDeadUsersOfConstant - If the specified constantexpr is dead, remove |
| /// it. This involves recursively eliminating any dead users of the |
| /// constantexpr. |
| static bool removeDeadUsersOfConstant(const Constant *C) { |
| if (isa<GlobalValue>(C)) return false; // Cannot remove this |
| |
| while (!C->use_empty()) { |
| const Constant *User = dyn_cast<Constant>(C->use_back()); |
| if (!User) return false; // Non-constant usage; |
| if (!removeDeadUsersOfConstant(User)) |
| return false; // Constant wasn't dead |
| } |
| |
| const_cast<Constant*>(C)->destroyConstant(); |
| return true; |
| } |
| |
| /// removeDeadConstantUsers - If there are any dead constant users dangling |
| /// off of this global value, remove them. This method is useful for clients |
| /// that want to check to see if a global is unused, but don't want to deal |
| /// with potentially dead constants hanging off of the globals. |
| void GlobalValue::removeDeadConstantUsers() const { |
| Value::use_const_iterator I = use_begin(), E = use_end(); |
| Value::use_const_iterator LastNonDeadUser = E; |
| while (I != E) { |
| if (const Constant *User = dyn_cast<Constant>(*I)) { |
| if (!removeDeadUsersOfConstant(User)) { |
| // If the constant wasn't dead, remember that this was the last live use |
| // and move on to the next constant. |
| LastNonDeadUser = I; |
| ++I; |
| } else { |
| // If the constant was dead, then the iterator is invalidated. |
| if (LastNonDeadUser == E) { |
| I = use_begin(); |
| if (I == E) break; |
| } else { |
| I = LastNonDeadUser; |
| ++I; |
| } |
| } |
| } else { |
| LastNonDeadUser = I; |
| ++I; |
| } |
| } |
| } |
| |
| /// 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) { |
| setAlignment(Src->getAlignment()); |
| setSection(Src->getSection()); |
| setVisibility(Src->getVisibility()); |
| } |
| |
| |
| //===----------------------------------------------------------------------===// |
| // GlobalVariable Implementation |
| //===----------------------------------------------------------------------===// |
| |
| GlobalVariable::GlobalVariable(LLVMContext &Context, const Type *Ty, |
| bool constant, LinkageTypes Link, |
| Constant *InitVal, const std::string &Name, |
| bool ThreadLocal, unsigned AddressSpace) |
| : GlobalValue(Context.getPointerType(Ty, AddressSpace), |
| Value::GlobalVariableVal, |
| OperandTraits<GlobalVariable>::op_begin(this), |
| InitVal != 0, Link, Name), |
| isConstantGlobal(constant), isThreadLocalSymbol(ThreadLocal) { |
| if (InitVal) { |
| assert(InitVal->getType() == Ty && |
| "Initializer should be the same type as the GlobalVariable!"); |
| Op<0>() = InitVal; |
| } |
| |
| LeakDetector::addGarbageObject(this); |
| } |
| |
| GlobalVariable::GlobalVariable(Module &M, const Type *Ty, bool constant, |
| LinkageTypes Link, Constant *InitVal, |
| const std::string &Name, |
| GlobalVariable *Before, bool ThreadLocal, |
| unsigned AddressSpace) |
| : GlobalValue(M.getContext().getPointerType(Ty, AddressSpace), |
| Value::GlobalVariableVal, |
| OperandTraits<GlobalVariable>::op_begin(this), |
| InitVal != 0, Link, Name), |
| isConstantGlobal(constant), isThreadLocalSymbol(ThreadLocal) { |
| if (InitVal) { |
| assert(InitVal->getType() == Ty && |
| "Initializer should be the same type as the GlobalVariable!"); |
| Op<0>() = InitVal; |
| } |
| |
| LeakDetector::addGarbageObject(this); |
| |
| if (Before) |
| Before->getParent()->getGlobalList().insert(Before, this); |
| else |
| M.getGlobalList().push_back(this); |
| } |
| |
| void GlobalVariable::setParent(Module *parent) { |
| if (getParent()) |
| LeakDetector::addGarbageObject(this); |
| Parent = parent; |
| if (getParent()) |
| LeakDetector::removeGarbageObject(this); |
| } |
| |
| 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)); |
| } |
| |
| /// 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!"); |
| GlobalValue::copyAttributesFrom(Src); |
| const GlobalVariable *SrcVar = cast<GlobalVariable>(Src); |
| setThreadLocal(SrcVar->isThreadLocal()); |
| } |
| |
| |
| //===----------------------------------------------------------------------===// |
| // GlobalAlias Implementation |
| //===----------------------------------------------------------------------===// |
| |
| GlobalAlias::GlobalAlias(const Type *Ty, LinkageTypes Link, |
| const std::string &Name, Constant* aliasee, |
| Module *ParentModule) |
| : GlobalValue(Ty, Value::GlobalAliasVal, &Op<0>(), 1, Link, Name) { |
| LeakDetector::addGarbageObject(this); |
| |
| if (aliasee) |
| assert(aliasee->getType() == Ty && "Alias and aliasee types should match!"); |
| Op<0>() = aliasee; |
| |
| if (ParentModule) |
| ParentModule->getAliasList().push_back(this); |
| } |
| |
| void GlobalAlias::setParent(Module *parent) { |
| if (getParent()) |
| LeakDetector::addGarbageObject(this); |
| Parent = parent; |
| if (getParent()) |
| LeakDetector::removeGarbageObject(this); |
| } |
| |
| void GlobalAlias::removeFromParent() { |
| getParent()->getAliasList().remove(this); |
| } |
| |
| void GlobalAlias::eraseFromParent() { |
| getParent()->getAliasList().erase(this); |
| } |
| |
| bool GlobalAlias::isDeclaration() const { |
| const GlobalValue* AV = getAliasedGlobal(); |
| if (AV) |
| return AV->isDeclaration(); |
| else |
| return false; |
| } |
| |
| void GlobalAlias::setAliasee(Constant *Aliasee) |
| { |
| if (Aliasee) |
| assert(Aliasee->getType() == getType() && |
| "Alias and aliasee types should match!"); |
| |
| setOperand(0, Aliasee); |
| } |
| |
| const GlobalValue *GlobalAlias::getAliasedGlobal() const { |
| const Constant *C = getAliasee(); |
| if (C) { |
| if (const GlobalValue *GV = dyn_cast<GlobalValue>(C)) |
| return GV; |
| else { |
| const ConstantExpr *CE = 0; |
| if ((CE = dyn_cast<ConstantExpr>(C)) && |
| (CE->getOpcode() == Instruction::BitCast || |
| CE->getOpcode() == Instruction::GetElementPtr)) |
| return dyn_cast<GlobalValue>(CE->getOperand(0)); |
| else |
| llvm_unreachable("Unsupported aliasee"); |
| } |
| } |
| return 0; |
| } |
| |
| const GlobalValue *GlobalAlias::resolveAliasedGlobal(bool stopOnWeak) const { |
| SmallPtrSet<const GlobalValue*, 3> Visited; |
| |
| // Check if we need to stop early. |
| if (stopOnWeak && mayBeOverridden()) |
| return this; |
| |
| const GlobalValue *GV = getAliasedGlobal(); |
| Visited.insert(GV); |
| |
| // Iterate over aliasing chain, stopping on weak alias if necessary. |
| while (const GlobalAlias *GA = dyn_cast<GlobalAlias>(GV)) { |
| if (stopOnWeak && GA->mayBeOverridden()) |
| break; |
| |
| GV = GA->getAliasedGlobal(); |
| |
| if (!Visited.insert(GV)) |
| return NULL; |
| } |
| |
| return GV; |
| } |