504 lines
15 KiB
C++
504 lines
15 KiB
C++
//===-- CGValue.h - LLVM CodeGen wrappers for llvm::Value* ------*- C++ -*-===//
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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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// These classes implement wrappers around llvm::Value in order to
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// fully represent the range of values for C L- and R- values.
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//
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//===----------------------------------------------------------------------===//
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#ifndef CLANG_CODEGEN_CGVALUE_H
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#define CLANG_CODEGEN_CGVALUE_H
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#include "clang/AST/ASTContext.h"
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#include "clang/AST/CharUnits.h"
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#include "clang/AST/Type.h"
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#include "llvm/IR/Value.h"
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namespace llvm {
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class Constant;
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class MDNode;
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}
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namespace clang {
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namespace CodeGen {
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class AggValueSlot;
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struct CGBitFieldInfo;
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/// RValue - This trivial value class is used to represent the result of an
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/// expression that is evaluated. It can be one of three things: either a
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/// simple LLVM SSA value, a pair of SSA values for complex numbers, or the
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/// address of an aggregate value in memory.
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class RValue {
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enum Flavor { Scalar, Complex, Aggregate };
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// Stores first value and flavor.
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llvm::PointerIntPair<llvm::Value *, 2, Flavor> V1;
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// Stores second value and volatility.
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llvm::PointerIntPair<llvm::Value *, 1, bool> V2;
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public:
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bool isScalar() const { return V1.getInt() == Scalar; }
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bool isComplex() const { return V1.getInt() == Complex; }
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bool isAggregate() const { return V1.getInt() == Aggregate; }
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bool isVolatileQualified() const { return V2.getInt(); }
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/// getScalarVal() - Return the Value* of this scalar value.
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llvm::Value *getScalarVal() const {
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assert(isScalar() && "Not a scalar!");
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return V1.getPointer();
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}
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/// getComplexVal - Return the real/imag components of this complex value.
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///
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std::pair<llvm::Value *, llvm::Value *> getComplexVal() const {
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return std::make_pair(V1.getPointer(), V2.getPointer());
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}
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/// getAggregateAddr() - Return the Value* of the address of the aggregate.
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llvm::Value *getAggregateAddr() const {
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assert(isAggregate() && "Not an aggregate!");
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return V1.getPointer();
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}
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static RValue get(llvm::Value *V) {
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RValue ER;
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ER.V1.setPointer(V);
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ER.V1.setInt(Scalar);
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ER.V2.setInt(false);
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return ER;
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}
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static RValue getComplex(llvm::Value *V1, llvm::Value *V2) {
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RValue ER;
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ER.V1.setPointer(V1);
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ER.V2.setPointer(V2);
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ER.V1.setInt(Complex);
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ER.V2.setInt(false);
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return ER;
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}
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static RValue getComplex(const std::pair<llvm::Value *, llvm::Value *> &C) {
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return getComplex(C.first, C.second);
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}
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// FIXME: Aggregate rvalues need to retain information about whether they are
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// volatile or not. Remove default to find all places that probably get this
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// wrong.
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static RValue getAggregate(llvm::Value *V, bool Volatile = false) {
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RValue ER;
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ER.V1.setPointer(V);
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ER.V1.setInt(Aggregate);
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ER.V2.setInt(Volatile);
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return ER;
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}
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};
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/// Does an ARC strong l-value have precise lifetime?
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enum ARCPreciseLifetime_t {
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ARCImpreciseLifetime, ARCPreciseLifetime
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};
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/// LValue - This represents an lvalue references. Because C/C++ allow
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/// bitfields, this is not a simple LLVM pointer, it may be a pointer plus a
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/// bitrange.
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class LValue {
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enum {
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Simple, // This is a normal l-value, use getAddress().
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VectorElt, // This is a vector element l-value (V[i]), use getVector*
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BitField, // This is a bitfield l-value, use getBitfield*.
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ExtVectorElt, // This is an extended vector subset, use getExtVectorComp
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GlobalReg // This is a register l-value, use getGlobalReg()
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} LVType;
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llvm::Value *V;
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union {
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// Index into a vector subscript: V[i]
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llvm::Value *VectorIdx;
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// ExtVector element subset: V.xyx
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llvm::Constant *VectorElts;
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// BitField start bit and size
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const CGBitFieldInfo *BitFieldInfo;
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};
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QualType Type;
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// 'const' is unused here
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Qualifiers Quals;
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// The alignment to use when accessing this lvalue. (For vector elements,
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// this is the alignment of the whole vector.)
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int64_t Alignment;
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// objective-c's ivar
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bool Ivar:1;
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// objective-c's ivar is an array
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bool ObjIsArray:1;
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// LValue is non-gc'able for any reason, including being a parameter or local
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// variable.
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bool NonGC: 1;
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// Lvalue is a global reference of an objective-c object
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bool GlobalObjCRef : 1;
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// Lvalue is a thread local reference
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bool ThreadLocalRef : 1;
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// Lvalue has ARC imprecise lifetime. We store this inverted to try
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// to make the default bitfield pattern all-zeroes.
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bool ImpreciseLifetime : 1;
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Expr *BaseIvarExp;
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/// Used by struct-path-aware TBAA.
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QualType TBAABaseType;
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/// Offset relative to the base type.
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uint64_t TBAAOffset;
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/// TBAAInfo - TBAA information to attach to dereferences of this LValue.
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llvm::MDNode *TBAAInfo;
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private:
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void Initialize(QualType Type, Qualifiers Quals,
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CharUnits Alignment,
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llvm::MDNode *TBAAInfo = nullptr) {
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this->Type = Type;
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this->Quals = Quals;
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this->Alignment = Alignment.getQuantity();
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assert(this->Alignment == Alignment.getQuantity() &&
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"Alignment exceeds allowed max!");
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// Initialize Objective-C flags.
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this->Ivar = this->ObjIsArray = this->NonGC = this->GlobalObjCRef = false;
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this->ImpreciseLifetime = false;
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this->ThreadLocalRef = false;
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this->BaseIvarExp = nullptr;
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// Initialize fields for TBAA.
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this->TBAABaseType = Type;
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this->TBAAOffset = 0;
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this->TBAAInfo = TBAAInfo;
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}
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public:
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bool isSimple() const { return LVType == Simple; }
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bool isVectorElt() const { return LVType == VectorElt; }
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bool isBitField() const { return LVType == BitField; }
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bool isExtVectorElt() const { return LVType == ExtVectorElt; }
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bool isGlobalReg() const { return LVType == GlobalReg; }
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bool isVolatileQualified() const { return Quals.hasVolatile(); }
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bool isRestrictQualified() const { return Quals.hasRestrict(); }
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unsigned getVRQualifiers() const {
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return Quals.getCVRQualifiers() & ~Qualifiers::Const;
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}
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QualType getType() const { return Type; }
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Qualifiers::ObjCLifetime getObjCLifetime() const {
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return Quals.getObjCLifetime();
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}
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bool isObjCIvar() const { return Ivar; }
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void setObjCIvar(bool Value) { Ivar = Value; }
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bool isObjCArray() const { return ObjIsArray; }
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void setObjCArray(bool Value) { ObjIsArray = Value; }
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bool isNonGC () const { return NonGC; }
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void setNonGC(bool Value) { NonGC = Value; }
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bool isGlobalObjCRef() const { return GlobalObjCRef; }
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void setGlobalObjCRef(bool Value) { GlobalObjCRef = Value; }
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bool isThreadLocalRef() const { return ThreadLocalRef; }
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void setThreadLocalRef(bool Value) { ThreadLocalRef = Value;}
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ARCPreciseLifetime_t isARCPreciseLifetime() const {
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return ARCPreciseLifetime_t(!ImpreciseLifetime);
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}
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void setARCPreciseLifetime(ARCPreciseLifetime_t value) {
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ImpreciseLifetime = (value == ARCImpreciseLifetime);
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}
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bool isObjCWeak() const {
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return Quals.getObjCGCAttr() == Qualifiers::Weak;
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}
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bool isObjCStrong() const {
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return Quals.getObjCGCAttr() == Qualifiers::Strong;
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}
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bool isVolatile() const {
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return Quals.hasVolatile();
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}
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Expr *getBaseIvarExp() const { return BaseIvarExp; }
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void setBaseIvarExp(Expr *V) { BaseIvarExp = V; }
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QualType getTBAABaseType() const { return TBAABaseType; }
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void setTBAABaseType(QualType T) { TBAABaseType = T; }
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uint64_t getTBAAOffset() const { return TBAAOffset; }
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void setTBAAOffset(uint64_t O) { TBAAOffset = O; }
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llvm::MDNode *getTBAAInfo() const { return TBAAInfo; }
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void setTBAAInfo(llvm::MDNode *N) { TBAAInfo = N; }
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const Qualifiers &getQuals() const { return Quals; }
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Qualifiers &getQuals() { return Quals; }
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unsigned getAddressSpace() const { return Quals.getAddressSpace(); }
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CharUnits getAlignment() const { return CharUnits::fromQuantity(Alignment); }
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void setAlignment(CharUnits A) { Alignment = A.getQuantity(); }
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// simple lvalue
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llvm::Value *getAddress() const { assert(isSimple()); return V; }
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void setAddress(llvm::Value *address) {
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assert(isSimple());
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V = address;
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}
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// vector elt lvalue
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llvm::Value *getVectorAddr() const { assert(isVectorElt()); return V; }
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llvm::Value *getVectorIdx() const { assert(isVectorElt()); return VectorIdx; }
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// extended vector elements.
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llvm::Value *getExtVectorAddr() const { assert(isExtVectorElt()); return V; }
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llvm::Constant *getExtVectorElts() const {
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assert(isExtVectorElt());
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return VectorElts;
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}
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// bitfield lvalue
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llvm::Value *getBitFieldAddr() const {
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assert(isBitField());
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return V;
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}
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const CGBitFieldInfo &getBitFieldInfo() const {
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assert(isBitField());
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return *BitFieldInfo;
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}
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// global register lvalue
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llvm::Value *getGlobalReg() const { assert(isGlobalReg()); return V; }
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static LValue MakeAddr(llvm::Value *address, QualType type,
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CharUnits alignment, ASTContext &Context,
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llvm::MDNode *TBAAInfo = nullptr) {
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Qualifiers qs = type.getQualifiers();
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qs.setObjCGCAttr(Context.getObjCGCAttrKind(type));
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LValue R;
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R.LVType = Simple;
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R.V = address;
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R.Initialize(type, qs, alignment, TBAAInfo);
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return R;
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}
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static LValue MakeVectorElt(llvm::Value *Vec, llvm::Value *Idx,
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QualType type, CharUnits Alignment) {
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LValue R;
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R.LVType = VectorElt;
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R.V = Vec;
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R.VectorIdx = Idx;
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R.Initialize(type, type.getQualifiers(), Alignment);
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return R;
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}
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static LValue MakeExtVectorElt(llvm::Value *Vec, llvm::Constant *Elts,
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QualType type, CharUnits Alignment) {
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LValue R;
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R.LVType = ExtVectorElt;
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R.V = Vec;
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R.VectorElts = Elts;
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R.Initialize(type, type.getQualifiers(), Alignment);
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return R;
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}
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/// \brief Create a new object to represent a bit-field access.
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///
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/// \param Addr - The base address of the bit-field sequence this
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/// bit-field refers to.
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/// \param Info - The information describing how to perform the bit-field
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/// access.
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static LValue MakeBitfield(llvm::Value *Addr,
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const CGBitFieldInfo &Info,
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QualType type, CharUnits Alignment) {
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LValue R;
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R.LVType = BitField;
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R.V = Addr;
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R.BitFieldInfo = &Info;
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R.Initialize(type, type.getQualifiers(), Alignment);
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return R;
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}
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static LValue MakeGlobalReg(llvm::Value *Reg,
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QualType type,
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CharUnits Alignment) {
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LValue R;
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R.LVType = GlobalReg;
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R.V = Reg;
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R.Initialize(type, type.getQualifiers(), Alignment);
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return R;
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}
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RValue asAggregateRValue() const {
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// FIMXE: Alignment
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return RValue::getAggregate(getAddress(), isVolatileQualified());
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}
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};
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/// An aggregate value slot.
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class AggValueSlot {
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/// The address.
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llvm::Value *Addr;
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// Qualifiers
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Qualifiers Quals;
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unsigned short Alignment;
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/// DestructedFlag - This is set to true if some external code is
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/// responsible for setting up a destructor for the slot. Otherwise
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/// the code which constructs it should push the appropriate cleanup.
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bool DestructedFlag : 1;
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/// ObjCGCFlag - This is set to true if writing to the memory in the
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/// slot might require calling an appropriate Objective-C GC
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/// barrier. The exact interaction here is unnecessarily mysterious.
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bool ObjCGCFlag : 1;
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/// ZeroedFlag - This is set to true if the memory in the slot is
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/// known to be zero before the assignment into it. This means that
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/// zero fields don't need to be set.
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bool ZeroedFlag : 1;
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/// AliasedFlag - This is set to true if the slot might be aliased
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/// and it's not undefined behavior to access it through such an
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/// alias. Note that it's always undefined behavior to access a C++
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/// object that's under construction through an alias derived from
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/// outside the construction process.
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///
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/// This flag controls whether calls that produce the aggregate
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/// value may be evaluated directly into the slot, or whether they
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/// must be evaluated into an unaliased temporary and then memcpy'ed
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/// over. Since it's invalid in general to memcpy a non-POD C++
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/// object, it's important that this flag never be set when
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/// evaluating an expression which constructs such an object.
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bool AliasedFlag : 1;
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public:
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enum IsAliased_t { IsNotAliased, IsAliased };
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enum IsDestructed_t { IsNotDestructed, IsDestructed };
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enum IsZeroed_t { IsNotZeroed, IsZeroed };
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enum NeedsGCBarriers_t { DoesNotNeedGCBarriers, NeedsGCBarriers };
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/// ignored - Returns an aggregate value slot indicating that the
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/// aggregate value is being ignored.
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static AggValueSlot ignored() {
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return forAddr(nullptr, CharUnits(), Qualifiers(), IsNotDestructed,
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DoesNotNeedGCBarriers, IsNotAliased);
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}
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/// forAddr - Make a slot for an aggregate value.
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///
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/// \param quals - The qualifiers that dictate how the slot should
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/// be initialied. Only 'volatile' and the Objective-C lifetime
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/// qualifiers matter.
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///
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/// \param isDestructed - true if something else is responsible
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/// for calling destructors on this object
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/// \param needsGC - true if the slot is potentially located
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/// somewhere that ObjC GC calls should be emitted for
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static AggValueSlot forAddr(llvm::Value *addr, CharUnits align,
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Qualifiers quals,
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IsDestructed_t isDestructed,
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NeedsGCBarriers_t needsGC,
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IsAliased_t isAliased,
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IsZeroed_t isZeroed = IsNotZeroed) {
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AggValueSlot AV;
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AV.Addr = addr;
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AV.Alignment = align.getQuantity();
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AV.Quals = quals;
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AV.DestructedFlag = isDestructed;
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AV.ObjCGCFlag = needsGC;
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AV.ZeroedFlag = isZeroed;
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AV.AliasedFlag = isAliased;
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return AV;
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}
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static AggValueSlot forLValue(const LValue &LV,
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IsDestructed_t isDestructed,
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NeedsGCBarriers_t needsGC,
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IsAliased_t isAliased,
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IsZeroed_t isZeroed = IsNotZeroed) {
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return forAddr(LV.getAddress(), LV.getAlignment(),
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LV.getQuals(), isDestructed, needsGC, isAliased, isZeroed);
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}
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IsDestructed_t isExternallyDestructed() const {
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return IsDestructed_t(DestructedFlag);
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}
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void setExternallyDestructed(bool destructed = true) {
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DestructedFlag = destructed;
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}
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Qualifiers getQualifiers() const { return Quals; }
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bool isVolatile() const {
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return Quals.hasVolatile();
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}
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void setVolatile(bool flag) {
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Quals.setVolatile(flag);
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}
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Qualifiers::ObjCLifetime getObjCLifetime() const {
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return Quals.getObjCLifetime();
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}
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NeedsGCBarriers_t requiresGCollection() const {
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return NeedsGCBarriers_t(ObjCGCFlag);
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}
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llvm::Value *getAddr() const {
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return Addr;
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}
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bool isIgnored() const {
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return Addr == nullptr;
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}
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CharUnits getAlignment() const {
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return CharUnits::fromQuantity(Alignment);
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}
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IsAliased_t isPotentiallyAliased() const {
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return IsAliased_t(AliasedFlag);
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}
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// FIXME: Alignment?
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RValue asRValue() const {
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return RValue::getAggregate(getAddr(), isVolatile());
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}
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void setZeroed(bool V = true) { ZeroedFlag = V; }
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IsZeroed_t isZeroed() const {
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return IsZeroed_t(ZeroedFlag);
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}
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};
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} // end namespace CodeGen
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} // end namespace clang
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#endif
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