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Diffstat (limited to 'lib/VMCore/Globals.cpp')
| -rw-r--r-- | lib/VMCore/Globals.cpp | 230 |
1 files changed, 230 insertions, 0 deletions
diff --git a/lib/VMCore/Globals.cpp b/lib/VMCore/Globals.cpp new file mode 100644 index 0000000..eb0df60 --- /dev/null +++ b/lib/VMCore/Globals.cpp @@ -0,0 +1,230 @@ +//===-- Globals.cpp - Implement the GlobalValue & GlobalVariable class ----===// +// +// The LLVM Compiler Infrastructure +// +// This file was developed by the LLVM research group and 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/Module.h" +#include "llvm/Support/LeakDetector.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(Constant *C) { + if (isa<GlobalValue>(C)) return false; // Cannot remove this + + while (!C->use_empty()) { + Constant *User = dyn_cast<Constant>(C->use_back()); + if (!User) return false; // Non-constant usage; + if (!removeDeadUsersOfConstant(User)) + return false; // Constant wasn't dead + } + + 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() { + Value::use_iterator I = use_begin(), E = use_end(); + Value::use_iterator LastNonDeadUser = E; + while (I != E) { + if (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() { + assert(0 && "You can't GV->destroyConstant()!"); + abort(); +} + +//===----------------------------------------------------------------------===// +// GlobalVariable Implementation +//===----------------------------------------------------------------------===// + +GlobalVariable::GlobalVariable(const Type *Ty, bool constant, LinkageTypes Link, + Constant *InitVal, const std::string &Name, + Module *ParentModule, bool ThreadLocal) + : GlobalValue(PointerType::get(Ty), Value::GlobalVariableVal, + &Initializer, InitVal != 0, Link, Name), + isConstantGlobal(constant), isThreadLocalSymbol(ThreadLocal) { + if (InitVal) { + assert(InitVal->getType() == Ty && + "Initializer should be the same type as the GlobalVariable!"); + Initializer.init(InitVal, this); + } else { + Initializer.init(0, this); + } + + LeakDetector::addGarbageObject(this); + + if (ParentModule) + ParentModule->getGlobalList().push_back(this); +} + +GlobalVariable::GlobalVariable(const Type *Ty, bool constant, LinkageTypes Link, + Constant *InitVal, const std::string &Name, + GlobalVariable *Before, bool ThreadLocal) + : GlobalValue(PointerType::get(Ty), Value::GlobalVariableVal, + &Initializer, InitVal != 0, Link, Name), + isConstantGlobal(constant), isThreadLocalSymbol(ThreadLocal) { + if (InitVal) { + assert(InitVal->getType() == Ty && + "Initializer should be the same type as the GlobalVariable!"); + Initializer.init(InitVal, this); + } else { + Initializer.init(0, this); + } + + LeakDetector::addGarbageObject(this); + + if (Before) + Before->getParent()->getGlobalList().insert(Before, 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)); +} + +//===----------------------------------------------------------------------===// +// GlobalAlias Implementation +//===----------------------------------------------------------------------===// + +GlobalAlias::GlobalAlias(const Type *Ty, LinkageTypes Link, + const std::string &Name, Constant* aliasee, + Module *ParentModule) + : GlobalValue(Ty, Value::GlobalAliasVal, &Aliasee, 1, Link, Name) { + LeakDetector::addGarbageObject(this); + + if (aliasee) + assert(aliasee->getType() == Ty && "Alias and aliasee types should match!"); + Aliasee.init(aliasee, this); + + 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 + assert(0 && "Unsupported aliasee"); + } + } + return 0; +} + |