-//===-- Globals.cpp - Implement the Global object classes -----------------===//
+//===-- 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 is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
//
//===----------------------------------------------------------------------===//
-#include "llvm/DerivedTypes.h"
+#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/SymbolTable.h"
+#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/Support/LeakDetector.h"
using namespace llvm;
// GlobalValue Class
//===----------------------------------------------------------------------===//
-/// This could be named "SafeToDestroyGlobalValue". It just makes sure that
-/// there are no non-constant uses of this GlobalValue. If there aren't then
-/// this and the transitive closure of the constants can be deleted. See the
-/// destructor for details.
-static bool removeDeadConstantUsers(Constant* C) {
+/// 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())
- if (Constant *User = dyn_cast<Constant>(C->use_back())) {
- if (!removeDeadConstantUsers(User))
- return false; // Constant wasn't dead
- } else {
- return false; // Non-constant usage;
- }
+ 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
+ }
- C->destroyConstant();
+ const_cast<Constant*>(C)->destroyConstant();
return true;
}
/// 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.
-///
-/// This function returns true if the global value is now dead. If all
-/// users of this global are not dead, this method may return false and
-/// leave some of them around.
-void GlobalValue::removeDeadConstantUsers() {
- while(!use_empty()) {
- if (Constant* User = dyn_cast<Constant>(use_back())) {
- if (!::removeDeadConstantUsers(User))
- return; // Constant wasn't dead
+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 {
- return; // Non-constant usage;
+ LastNonDeadUser = I;
+ ++I;
}
}
}
assert(0 && "You can't GV->destroyConstant()!");
abort();
}
+
+/// 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(const Type *Ty, bool constant, LinkageTypes Link,
- Constant *InitVal,
- const std::string &Name, Module *ParentModule)
- : GlobalValue(PointerType::get(Ty), Value::GlobalVariableVal,
- &Initializer, InitVal != 0, Link, Name),
- isConstantGlobal(constant) {
+GlobalVariable::GlobalVariable(LLVMContext &Context, const Type *Ty,
+ bool constant, LinkageTypes Link,
+ Constant *InitVal, const std::string &Name,
+ Module *ParentModule, 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!");
- Initializer.init(InitVal, this);
- } else {
- Initializer.init(0, this);
+ Op<0>() = InitVal;
}
LeakDetector::addGarbageObject(this);
ParentModule->getGlobalList().push_back(this);
}
+GlobalVariable::GlobalVariable(LLVMContext &Context, const Type *Ty,
+ bool constant, LinkageTypes Link,
+ Constant *InitVal, const std::string &Name,
+ GlobalVariable *Before, 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);
+
+ if (Before)
+ Before->getParent()->getGlobalList().insert(Before, this);
+}
+
void GlobalVariable::setParent(Module *parent) {
if (getParent())
LeakDetector::addGarbageObject(this);
// 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
+ assert(0 && "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;
+}
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