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//===-- 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/GlobalVariable.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));
}
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