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			270 lines
		
	
	
		
			8.9 KiB
		
	
	
	
		
			C++
		
	
	
	
			
		
		
	
	
			270 lines
		
	
	
		
			8.9 KiB
		
	
	
	
		
			C++
		
	
	
	
| //===-- Globals.cpp - Implement the GlobalValue & GlobalVariable class ----===//
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| //
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| //                     The LLVM Compiler Infrastructure
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| //
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| // This file is distributed under the University of Illinois Open Source
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| // License. See LICENSE.TXT for details.
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| //
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| //===----------------------------------------------------------------------===//
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| //
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| // This file implements the GlobalValue & GlobalVariable classes for the IR
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| // library.
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| //
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| //===----------------------------------------------------------------------===//
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| 
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| #include "llvm/IR/GlobalValue.h"
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| #include "llvm/ADT/SmallPtrSet.h"
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| #include "llvm/IR/Constants.h"
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| #include "llvm/IR/DerivedTypes.h"
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| #include "llvm/IR/GlobalAlias.h"
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| #include "llvm/IR/GlobalVariable.h"
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| #include "llvm/IR/Module.h"
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| #include "llvm/Support/ErrorHandling.h"
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| #include "llvm/Support/LeakDetector.h"
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| using namespace llvm;
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| 
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| //===----------------------------------------------------------------------===//
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| //                            GlobalValue Class
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| //===----------------------------------------------------------------------===//
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| 
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| bool GlobalValue::isMaterializable() const {
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|   return getParent() && getParent()->isMaterializable(this);
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| }
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| bool GlobalValue::isDematerializable() const {
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|   return getParent() && getParent()->isDematerializable(this);
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| }
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| bool GlobalValue::Materialize(std::string *ErrInfo) {
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|   return getParent()->Materialize(this, ErrInfo);
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| }
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| void GlobalValue::Dematerialize() {
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|   getParent()->Dematerialize(this);
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| }
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| 
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| /// Override destroyConstant to make sure it doesn't get called on
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| /// GlobalValue's because they shouldn't be treated like other constants.
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| void GlobalValue::destroyConstant() {
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|   llvm_unreachable("You can't GV->destroyConstant()!");
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| }
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| 
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| /// copyAttributesFrom - copy all additional attributes (those not needed to
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| /// create a GlobalValue) from the GlobalValue Src to this one.
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| void GlobalValue::copyAttributesFrom(const GlobalValue *Src) {
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|   setAlignment(Src->getAlignment());
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|   setSection(Src->getSection());
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|   setVisibility(Src->getVisibility());
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|   setUnnamedAddr(Src->hasUnnamedAddr());
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| }
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| 
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| void GlobalValue::setAlignment(unsigned Align) {
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|   assert((Align & (Align-1)) == 0 && "Alignment is not a power of 2!");
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|   assert(Align <= MaximumAlignment &&
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|          "Alignment is greater than MaximumAlignment!");
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|   Alignment = Log2_32(Align) + 1;
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|   assert(getAlignment() == Align && "Alignment representation error!");
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| }
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| 
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| bool GlobalValue::isDeclaration() const {
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|   // Globals are definitions if they have an initializer.
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|   if (const GlobalVariable *GV = dyn_cast<GlobalVariable>(this))
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|     return GV->getNumOperands() == 0;
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| 
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|   // Functions are definitions if they have a body.
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|   if (const Function *F = dyn_cast<Function>(this))
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|     return F->empty();
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| 
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|   // Aliases are always definitions.
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|   assert(isa<GlobalAlias>(this));
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|   return false;
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| }
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|   
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| //===----------------------------------------------------------------------===//
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| // GlobalVariable Implementation
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| //===----------------------------------------------------------------------===//
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| 
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| GlobalVariable::GlobalVariable(Type *Ty, bool constant, LinkageTypes Link,
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|                                Constant *InitVal,
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|                                const Twine &Name, ThreadLocalMode TLMode,
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|                                unsigned AddressSpace,
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|                                bool isExternallyInitialized)
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|   : GlobalValue(PointerType::get(Ty, AddressSpace),
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|                 Value::GlobalVariableVal,
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|                 OperandTraits<GlobalVariable>::op_begin(this),
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|                 InitVal != 0, Link, Name),
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|     isConstantGlobal(constant), threadLocalMode(TLMode),
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|     isExternallyInitializedConstant(isExternallyInitialized) {
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|   if (InitVal) {
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|     assert(InitVal->getType() == Ty &&
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|            "Initializer should be the same type as the GlobalVariable!");
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|     Op<0>() = InitVal;
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|   }
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| 
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|   LeakDetector::addGarbageObject(this);
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| }
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| 
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| GlobalVariable::GlobalVariable(Module &M, Type *Ty, bool constant,
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|                                LinkageTypes Link, Constant *InitVal,
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|                                const Twine &Name,
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|                                GlobalVariable *Before, ThreadLocalMode TLMode,
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|                                unsigned AddressSpace,
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|                                bool isExternallyInitialized)
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|   : GlobalValue(PointerType::get(Ty, AddressSpace),
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|                 Value::GlobalVariableVal,
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|                 OperandTraits<GlobalVariable>::op_begin(this),
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|                 InitVal != 0, Link, Name),
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|     isConstantGlobal(constant), threadLocalMode(TLMode),
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|     isExternallyInitializedConstant(isExternallyInitialized) {
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|   if (InitVal) {
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|     assert(InitVal->getType() == Ty &&
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|            "Initializer should be the same type as the GlobalVariable!");
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|     Op<0>() = InitVal;
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|   }
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|   
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|   LeakDetector::addGarbageObject(this);
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|   
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|   if (Before)
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|     Before->getParent()->getGlobalList().insert(Before, this);
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|   else
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|     M.getGlobalList().push_back(this);
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| }
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| 
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| void GlobalVariable::setParent(Module *parent) {
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|   if (getParent())
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|     LeakDetector::addGarbageObject(this);
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|   Parent = parent;
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|   if (getParent())
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|     LeakDetector::removeGarbageObject(this);
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| }
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| 
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| void GlobalVariable::removeFromParent() {
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|   getParent()->getGlobalList().remove(this);
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| }
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| 
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| void GlobalVariable::eraseFromParent() {
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|   getParent()->getGlobalList().erase(this);
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| }
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| 
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| void GlobalVariable::replaceUsesOfWithOnConstant(Value *From, Value *To,
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|                                                  Use *U) {
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|   // If you call this, then you better know this GVar has a constant
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|   // initializer worth replacing. Enforce that here.
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|   assert(getNumOperands() == 1 &&
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|          "Attempt to replace uses of Constants on a GVar with no initializer");
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| 
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|   // And, since you know it has an initializer, the From value better be
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|   // the initializer :)
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|   assert(getOperand(0) == From &&
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|          "Attempt to replace wrong constant initializer in GVar");
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| 
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|   // And, you better have a constant for the replacement value
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|   assert(isa<Constant>(To) &&
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|          "Attempt to replace GVar initializer with non-constant");
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| 
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|   // Okay, preconditions out of the way, replace the constant initializer.
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|   this->setOperand(0, cast<Constant>(To));
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| }
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| 
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| void GlobalVariable::setInitializer(Constant *InitVal) {
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|   if (InitVal == 0) {
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|     if (hasInitializer()) {
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|       Op<0>().set(0);
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|       NumOperands = 0;
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|     }
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|   } else {
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|     assert(InitVal->getType() == getType()->getElementType() &&
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|            "Initializer type must match GlobalVariable type");
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|     if (!hasInitializer())
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|       NumOperands = 1;
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|     Op<0>().set(InitVal);
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|   }
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| }
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| 
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| /// copyAttributesFrom - copy all additional attributes (those not needed to
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| /// create a GlobalVariable) from the GlobalVariable Src to this one.
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| void GlobalVariable::copyAttributesFrom(const GlobalValue *Src) {
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|   assert(isa<GlobalVariable>(Src) && "Expected a GlobalVariable!");
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|   GlobalValue::copyAttributesFrom(Src);
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|   const GlobalVariable *SrcVar = cast<GlobalVariable>(Src);
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|   setThreadLocal(SrcVar->isThreadLocal());
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| }
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| 
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| 
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| //===----------------------------------------------------------------------===//
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| // GlobalAlias Implementation
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| //===----------------------------------------------------------------------===//
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| 
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| GlobalAlias::GlobalAlias(Type *Ty, LinkageTypes Link,
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|                          const Twine &Name, Constant* aliasee,
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|                          Module *ParentModule)
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|   : GlobalValue(Ty, Value::GlobalAliasVal, &Op<0>(), 1, Link, Name) {
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|   LeakDetector::addGarbageObject(this);
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| 
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|   if (aliasee)
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|     assert(aliasee->getType() == Ty && "Alias and aliasee types should match!");
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|   Op<0>() = aliasee;
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| 
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|   if (ParentModule)
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|     ParentModule->getAliasList().push_back(this);
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| }
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| 
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| void GlobalAlias::setParent(Module *parent) {
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|   if (getParent())
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|     LeakDetector::addGarbageObject(this);
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|   Parent = parent;
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|   if (getParent())
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|     LeakDetector::removeGarbageObject(this);
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| }
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| 
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| void GlobalAlias::removeFromParent() {
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|   getParent()->getAliasList().remove(this);
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| }
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| 
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| void GlobalAlias::eraseFromParent() {
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|   getParent()->getAliasList().erase(this);
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| }
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| 
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| void GlobalAlias::setAliasee(Constant *Aliasee) {
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|   assert((!Aliasee || Aliasee->getType() == getType()) &&
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|          "Alias and aliasee types should match!");
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|   
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|   setOperand(0, Aliasee);
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| }
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| 
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| GlobalValue *GlobalAlias::getAliasedGlobal() {
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|   Constant *C = getAliasee();
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|   if (C == 0) return 0;
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|   
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|   if (GlobalValue *GV = dyn_cast<GlobalValue>(C))
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|     return GV;
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| 
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|   ConstantExpr *CE = cast<ConstantExpr>(C);
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|   assert((CE->getOpcode() == Instruction::BitCast || 
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|           CE->getOpcode() == Instruction::GetElementPtr) &&
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|          "Unsupported aliasee");
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|   
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|   return cast<GlobalValue>(CE->getOperand(0));
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| }
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| 
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| GlobalValue *GlobalAlias::resolveAliasedGlobal(bool stopOnWeak) {
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|   SmallPtrSet<GlobalValue*, 3> Visited;
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| 
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|   // Check if we need to stop early.
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|   if (stopOnWeak && mayBeOverridden())
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|     return this;
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| 
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|   GlobalValue *GV = getAliasedGlobal();
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|   Visited.insert(GV);
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| 
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|   // Iterate over aliasing chain, stopping on weak alias if necessary.
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|   while (GlobalAlias *GA = dyn_cast<GlobalAlias>(GV)) {
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|     if (stopOnWeak && GA->mayBeOverridden())
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|       break;
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| 
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|     GV = GA->getAliasedGlobal();
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| 
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|     if (!Visited.insert(GV))
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|       return 0;
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|   }
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| 
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|   return GV;
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| }
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