clang/lib/CodeGen/CGValue.h

   1 //===-- CGValue.h - LLVM CodeGen wrappers for llvm::Value* ------*- C++ -*-===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8 //
   9 // These classes implement wrappers around llvm::Value in order to
  10 // fully represent the range of values for C L- and R- values.
  11 //
  12 //===----------------------------------------------------------------------===//
  13
  14 #ifndef LLVM_CLANG_LIB_CODEGEN_CGVALUE_H
  15 #define LLVM_CLANG_LIB_CODEGEN_CGVALUE_H
  16
  17 #include "clang/AST/ASTContext.h"
  18 #include "clang/AST/Type.h"
  19 #include "llvm/IR/Value.h"
  20 #include "llvm/IR/Type.h"
  21 #include "Address.h"
  22 #include "CodeGenTBAA.h"
  23
  24 namespace llvm {
  25   class Constant;
  26   class MDNode;
  27 }
  28
  29 namespace clang {
  30 namespace CodeGen {
  31   class AggValueSlot;
  32   class CodeGenFunction;
  33   struct CGBitFieldInfo;
  34
  35 /// RValue - This trivial value class is used to represent the result of an
  36 /// expression that is evaluated.  It can be one of three things: either a
  37 /// simple LLVM SSA value, a pair of SSA values for complex numbers, or the
  38 /// address of an aggregate value in memory.
  39 class RValue {
  40   enum Flavor { Scalar, Complex, Aggregate };
  41
  42   // The shift to make to an aggregate's alignment to make it look
  43   // like a pointer.
  44   enum { AggAlignShift = 4 };
  45
  46   // Stores first value and flavor.
  47   llvm::PointerIntPair<llvm::Value *, 2, Flavor> V1;
  48   // Stores second value and volatility.
  49   llvm::PointerIntPair<llvm::Value *, 1, bool> V2;
  50   // Stores element type for aggregate values.
  51   llvm::Type *ElementType;
  52
  53 public:
  54   bool isScalar() const { return V1.getInt() == Scalar; }
  55   bool isComplex() const { return V1.getInt() == Complex; }
  56   bool isAggregate() const { return V1.getInt() == Aggregate; }
  57
  58   bool isVolatileQualified() const { return V2.getInt(); }
  59
  60   /// getScalarVal() - Return the Value* of this scalar value.
  61   llvm::Value *getScalarVal() const {
  62     assert(isScalar() && "Not a scalar!");
  63     return V1.getPointer();
  64   }
  65
  66   /// getComplexVal - Return the real/imag components of this complex value.
  67   ///
  68   std::pair<llvm::Value *, llvm::Value *> getComplexVal() const {
  69     return std::make_pair(V1.getPointer(), V2.getPointer());
  70   }
  71
  72   /// getAggregateAddr() - Return the Value* of the address of the aggregate.
  73   Address getAggregateAddress() const {
  74     assert(isAggregate() && "Not an aggregate!");
  75     auto align = reinterpret_cast<uintptr_t>(V2.getPointer()) >> AggAlignShift;
  76     return Address(
  77         V1.getPointer(), ElementType, CharUnits::fromQuantity(align));
  78   }
  79   llvm::Value *getAggregatePointer() const {
  80     assert(isAggregate() && "Not an aggregate!");
  81     return V1.getPointer();
  82   }
  83
  84   static RValue getIgnored() {
  85     // FIXME: should we make this a more explicit state?
  86     return get(nullptr);
  87   }
  88
  89   static RValue get(llvm::Value *V) {
  90     RValue ER;
  91     ER.V1.setPointer(V);
  92     ER.V1.setInt(Scalar);
  93     ER.V2.setInt(false);
  94     return ER;
  95   }
  96   static RValue getComplex(llvm::Value *V1, llvm::Value *V2) {
  97     RValue ER;
  98     ER.V1.setPointer(V1);
  99     ER.V2.setPointer(V2);
 100     ER.V1.setInt(Complex);
 101     ER.V2.setInt(false);
 102     return ER;
 103   }
 104   static RValue getComplex(const std::pair<llvm::Value *, llvm::Value *> &C) {
 105     return getComplex(C.first, C.second);
 106   }
 107   // FIXME: Aggregate rvalues need to retain information about whether they are
 108   // volatile or not.  Remove default to find all places that probably get this
 109   // wrong.
 110   static RValue getAggregate(Address addr, bool isVolatile = false) {
 111     RValue ER;
 112     ER.V1.setPointer(addr.getPointer());
 113     ER.V1.setInt(Aggregate);
 114     ER.ElementType = addr.getElementType();
 115
 116     auto align = static_cast<uintptr_t>(addr.getAlignment().getQuantity());
 117     ER.V2.setPointer(reinterpret_cast<llvm::Value*>(align << AggAlignShift));
 118     ER.V2.setInt(isVolatile);
 119     return ER;
 120   }
 121 };
 122
 123 /// Does an ARC strong l-value have precise lifetime?
 124 enum ARCPreciseLifetime_t {
 125   ARCImpreciseLifetime, ARCPreciseLifetime
 126 };
 127
 128 /// The source of the alignment of an l-value; an expression of
 129 /// confidence in the alignment actually matching the estimate.
 130 enum class AlignmentSource {
 131   /// The l-value was an access to a declared entity or something
 132   /// equivalently strong, like the address of an array allocated by a
 133   /// language runtime.
 134   Decl,
 135
 136   /// The l-value was considered opaque, so the alignment was
 137   /// determined from a type, but that type was an explicitly-aligned
 138   /// typedef.
 139   AttributedType,
 140
 141   /// The l-value was considered opaque, so the alignment was
 142   /// determined from a type.
 143   Type
 144 };
 145
 146 /// Given that the base address has the given alignment source, what's
 147 /// our confidence in the alignment of the field?
 148 static inline AlignmentSource getFieldAlignmentSource(AlignmentSource Source) {
 149   // For now, we don't distinguish fields of opaque pointers from
 150   // top-level declarations, but maybe we should.
 151   return AlignmentSource::Decl;
 152 }
 153
 154 class LValueBaseInfo {
 155   AlignmentSource AlignSource;
 156
 157 public:
 158   explicit LValueBaseInfo(AlignmentSource Source = AlignmentSource::Type)
 159     : AlignSource(Source) {}
 160   AlignmentSource getAlignmentSource() const { return AlignSource; }
 161   void setAlignmentSource(AlignmentSource Source) { AlignSource = Source; }
 162
 163   void mergeForCast(const LValueBaseInfo &Info) {
 164     setAlignmentSource(Info.getAlignmentSource());
 165   }
 166 };
 167
 168 /// LValue - This represents an lvalue references.  Because C/C++ allow
 169 /// bitfields, this is not a simple LLVM pointer, it may be a pointer plus a
 170 /// bitrange.
 171 class LValue {
 172   enum {
 173     Simple,       // This is a normal l-value, use getAddress().
 174     VectorElt,    // This is a vector element l-value (V[i]), use getVector*
 175     BitField,     // This is a bitfield l-value, use getBitfield*.
 176     ExtVectorElt, // This is an extended vector subset, use getExtVectorComp
 177     GlobalReg,    // This is a register l-value, use getGlobalReg()
 178     MatrixElt     // This is a matrix element, use getVector*
 179   } LVType;
 180
 181   llvm::Value *V;
 182   llvm::Type *ElementType;
 183
 184   union {
 185     // Index into a vector subscript: V[i]
 186     llvm::Value *VectorIdx;
 187
 188     // ExtVector element subset: V.xyx
 189     llvm::Constant *VectorElts;
 190
 191     // BitField start bit and size
 192     const CGBitFieldInfo *BitFieldInfo;
 193   };
 194
 195   QualType Type;
 196
 197   // 'const' is unused here
 198   Qualifiers Quals;
 199
 200   // The alignment to use when accessing this lvalue.  (For vector elements,
 201   // this is the alignment of the whole vector.)
 202   unsigned Alignment;
 203
 204   // objective-c's ivar
 205   bool Ivar:1;
 206
 207   // objective-c's ivar is an array
 208   bool ObjIsArray:1;
 209
 210   // LValue is non-gc'able for any reason, including being a parameter or local
 211   // variable.
 212   bool NonGC: 1;
 213
 214   // Lvalue is a global reference of an objective-c object
 215   bool GlobalObjCRef : 1;
 216
 217   // Lvalue is a thread local reference
 218   bool ThreadLocalRef : 1;
 219
 220   // Lvalue has ARC imprecise lifetime.  We store this inverted to try
 221   // to make the default bitfield pattern all-zeroes.
 222   bool ImpreciseLifetime : 1;
 223
 224   // This flag shows if a nontemporal load/stores should be used when accessing
 225   // this lvalue.
 226   bool Nontemporal : 1;
 227
 228   // The pointer is known not to be null.
 229   bool IsKnownNonNull : 1;
 230
 231   LValueBaseInfo BaseInfo;
 232   TBAAAccessInfo TBAAInfo;
 233
 234   Expr *BaseIvarExp;
 235
 236 private:
 237   void Initialize(QualType Type, Qualifiers Quals, CharUnits Alignment,
 238                   LValueBaseInfo BaseInfo, TBAAAccessInfo TBAAInfo) {
 239     assert((!Alignment.isZero() || Type->isIncompleteType()) &&
 240            "initializing l-value with zero alignment!");
 241     if (isGlobalReg())
 242       assert(ElementType == nullptr && "Global reg does not store elem type");
 243     else
 244       assert(ElementType != nullptr && "Must have elem type");
 245
 246     this->Type = Type;
 247     this->Quals = Quals;
 248     const unsigned MaxAlign = 1U << 31;
 249     this->Alignment = Alignment.getQuantity() <= MaxAlign
 250                           ? Alignment.getQuantity()
 251                           : MaxAlign;
 252     assert(this->Alignment == Alignment.getQuantity() &&
 253            "Alignment exceeds allowed max!");
 254     this->BaseInfo = BaseInfo;
 255     this->TBAAInfo = TBAAInfo;
 256
 257     // Initialize Objective-C flags.
 258     this->Ivar = this->ObjIsArray = this->NonGC = this->GlobalObjCRef = false;
 259     this->ImpreciseLifetime = false;
 260     this->Nontemporal = false;
 261     this->ThreadLocalRef = false;
 262     this->BaseIvarExp = nullptr;
 263   }
 264
 265 public:
 266   bool isSimple() const { return LVType == Simple; }
 267   bool isVectorElt() const { return LVType == VectorElt; }
 268   bool isBitField() const { return LVType == BitField; }
 269   bool isExtVectorElt() const { return LVType == ExtVectorElt; }
 270   bool isGlobalReg() const { return LVType == GlobalReg; }
 271   bool isMatrixElt() const { return LVType == MatrixElt; }
 272
 273   bool isVolatileQualified() const { return Quals.hasVolatile(); }
 274   bool isRestrictQualified() const { return Quals.hasRestrict(); }
 275   unsigned getVRQualifiers() const {
 276     return Quals.getCVRQualifiers() & ~Qualifiers::Const;
 277   }
 278
 279   QualType getType() const { return Type; }
 280
 281   Qualifiers::ObjCLifetime getObjCLifetime() const {
 282     return Quals.getObjCLifetime();
 283   }
 284
 285   bool isObjCIvar() const { return Ivar; }
 286   void setObjCIvar(bool Value) { Ivar = Value; }
 287
 288   bool isObjCArray() const { return ObjIsArray; }
 289   void setObjCArray(bool Value) { ObjIsArray = Value; }
 290
 291   bool isNonGC () const { return NonGC; }
 292   void setNonGC(bool Value) { NonGC = Value; }
 293
 294   bool isGlobalObjCRef() const { return GlobalObjCRef; }
 295   void setGlobalObjCRef(bool Value) { GlobalObjCRef = Value; }
 296
 297   bool isThreadLocalRef() const { return ThreadLocalRef; }
 298   void setThreadLocalRef(bool Value) { ThreadLocalRef = Value;}
 299
 300   ARCPreciseLifetime_t isARCPreciseLifetime() const {
 301     return ARCPreciseLifetime_t(!ImpreciseLifetime);
 302   }
 303   void setARCPreciseLifetime(ARCPreciseLifetime_t value) {
 304     ImpreciseLifetime = (value == ARCImpreciseLifetime);
 305   }
 306   bool isNontemporal() const { return Nontemporal; }
 307   void setNontemporal(bool Value) { Nontemporal = Value; }
 308
 309   bool isObjCWeak() const {
 310     return Quals.getObjCGCAttr() == Qualifiers::Weak;
 311   }
 312   bool isObjCStrong() const {
 313     return Quals.getObjCGCAttr() == Qualifiers::Strong;
 314   }
 315
 316   bool isVolatile() const {
 317     return Quals.hasVolatile();
 318   }
 319
 320   Expr *getBaseIvarExp() const { return BaseIvarExp; }
 321   void setBaseIvarExp(Expr *V) { BaseIvarExp = V; }
 322
 323   TBAAAccessInfo getTBAAInfo() const { return TBAAInfo; }
 324   void setTBAAInfo(TBAAAccessInfo Info) { TBAAInfo = Info; }
 325
 326   const Qualifiers &getQuals() const { return Quals; }
 327   Qualifiers &getQuals() { return Quals; }
 328
 329   LangAS getAddressSpace() const { return Quals.getAddressSpace(); }
 330
 331   CharUnits getAlignment() const { return CharUnits::fromQuantity(Alignment); }
 332   void setAlignment(CharUnits A) { Alignment = A.getQuantity(); }
 333
 334   LValueBaseInfo getBaseInfo() const { return BaseInfo; }
 335   void setBaseInfo(LValueBaseInfo Info) { BaseInfo = Info; }
 336
 337   KnownNonNull_t isKnownNonNull() const {
 338     return (KnownNonNull_t)IsKnownNonNull;
 339   }
 340   LValue setKnownNonNull() {
 341     IsKnownNonNull = true;
 342     return *this;
 343   }
 344
 345   // simple lvalue
 346   llvm::Value *getPointer(CodeGenFunction &CGF) const {
 347     assert(isSimple());
 348     return V;
 349   }
 350   Address getAddress(CodeGenFunction &CGF) const {
 351     return Address(getPointer(CGF), ElementType, getAlignment(),
 352                    isKnownNonNull());
 353   }
 354   void setAddress(Address address) {
 355     assert(isSimple());
 356     V = address.getPointer();
 357     ElementType = address.getElementType();
 358     Alignment = address.getAlignment().getQuantity();
 359     IsKnownNonNull = address.isKnownNonNull();
 360   }
 361
 362   // vector elt lvalue
 363   Address getVectorAddress() const {
 364     return Address(getVectorPointer(), ElementType, getAlignment(),
 365                    (KnownNonNull_t)isKnownNonNull());
 366   }
 367   llvm::Value *getVectorPointer() const {
 368     assert(isVectorElt());
 369     return V;
 370   }
 371   llvm::Value *getVectorIdx() const {
 372     assert(isVectorElt());
 373     return VectorIdx;
 374   }
 375
 376   Address getMatrixAddress() const {
 377     return Address(getMatrixPointer(), ElementType, getAlignment(),
 378                    (KnownNonNull_t)isKnownNonNull());
 379   }
 380   llvm::Value *getMatrixPointer() const {
 381     assert(isMatrixElt());
 382     return V;
 383   }
 384   llvm::Value *getMatrixIdx() const {
 385     assert(isMatrixElt());
 386     return VectorIdx;
 387   }
 388
 389   // extended vector elements.
 390   Address getExtVectorAddress() const {
 391     return Address(getExtVectorPointer(), ElementType, getAlignment(),
 392                    (KnownNonNull_t)isKnownNonNull());
 393   }
 394   llvm::Value *getExtVectorPointer() const {
 395     assert(isExtVectorElt());
 396     return V;
 397   }
 398   llvm::Constant *getExtVectorElts() const {
 399     assert(isExtVectorElt());
 400     return VectorElts;
 401   }
 402
 403   // bitfield lvalue
 404   Address getBitFieldAddress() const {
 405     return Address(getBitFieldPointer(), ElementType, getAlignment(),
 406                    (KnownNonNull_t)isKnownNonNull());
 407   }
 408   llvm::Value *getBitFieldPointer() const { assert(isBitField()); return V; }
 409   const CGBitFieldInfo &getBitFieldInfo() const {
 410     assert(isBitField());
 411     return *BitFieldInfo;
 412   }
 413
 414   // global register lvalue
 415   llvm::Value *getGlobalReg() const { assert(isGlobalReg()); return V; }
 416
 417   static LValue MakeAddr(Address address, QualType type, ASTContext &Context,
 418                          LValueBaseInfo BaseInfo, TBAAAccessInfo TBAAInfo) {
 419     Qualifiers qs = type.getQualifiers();
 420     qs.setObjCGCAttr(Context.getObjCGCAttrKind(type));
 421
 422     LValue R;
 423     R.LVType = Simple;
 424     assert(address.getPointer()->getType()->isPointerTy());
 425     R.V = address.getPointer();
 426     R.ElementType = address.getElementType();
 427     R.IsKnownNonNull = address.isKnownNonNull();
 428     R.Initialize(type, qs, address.getAlignment(), BaseInfo, TBAAInfo);
 429     return R;
 430   }
 431
 432   static LValue MakeVectorElt(Address vecAddress, llvm::Value *Idx,
 433                               QualType type, LValueBaseInfo BaseInfo,
 434                               TBAAAccessInfo TBAAInfo) {
 435     LValue R;
 436     R.LVType = VectorElt;
 437     R.V = vecAddress.getPointer();
 438     R.ElementType = vecAddress.getElementType();
 439     R.VectorIdx = Idx;
 440     R.IsKnownNonNull = vecAddress.isKnownNonNull();
 441     R.Initialize(type, type.getQualifiers(), vecAddress.getAlignment(),
 442                  BaseInfo, TBAAInfo);
 443     return R;
 444   }
 445
 446   static LValue MakeExtVectorElt(Address vecAddress, llvm::Constant *Elts,
 447                                  QualType type, LValueBaseInfo BaseInfo,
 448                                  TBAAAccessInfo TBAAInfo) {
 449     LValue R;
 450     R.LVType = ExtVectorElt;
 451     R.V = vecAddress.getPointer();
 452     R.ElementType = vecAddress.getElementType();
 453     R.VectorElts = Elts;
 454     R.IsKnownNonNull = vecAddress.isKnownNonNull();
 455     R.Initialize(type, type.getQualifiers(), vecAddress.getAlignment(),
 456                  BaseInfo, TBAAInfo);
 457     return R;
 458   }
 459
 460   /// Create a new object to represent a bit-field access.
 461   ///
 462   /// \param Addr - The base address of the bit-field sequence this
 463   /// bit-field refers to.
 464   /// \param Info - The information describing how to perform the bit-field
 465   /// access.
 466   static LValue MakeBitfield(Address Addr, const CGBitFieldInfo &Info,
 467                              QualType type, LValueBaseInfo BaseInfo,
 468                              TBAAAccessInfo TBAAInfo) {
 469     LValue R;
 470     R.LVType = BitField;
 471     R.V = Addr.getPointer();
 472     R.ElementType = Addr.getElementType();
 473     R.BitFieldInfo = &Info;
 474     R.IsKnownNonNull = Addr.isKnownNonNull();
 475     R.Initialize(type, type.getQualifiers(), Addr.getAlignment(), BaseInfo,
 476                  TBAAInfo);
 477     return R;
 478   }
 479
 480   static LValue MakeGlobalReg(llvm::Value *V, CharUnits alignment,
 481                               QualType type) {
 482     LValue R;
 483     R.LVType = GlobalReg;
 484     R.V = V;
 485     R.ElementType = nullptr;
 486     R.IsKnownNonNull = true;
 487     R.Initialize(type, type.getQualifiers(), alignment,
 488                  LValueBaseInfo(AlignmentSource::Decl), TBAAAccessInfo());
 489     return R;
 490   }
 491
 492   static LValue MakeMatrixElt(Address matAddress, llvm::Value *Idx,
 493                               QualType type, LValueBaseInfo BaseInfo,
 494                               TBAAAccessInfo TBAAInfo) {
 495     LValue R;
 496     R.LVType = MatrixElt;
 497     R.V = matAddress.getPointer();
 498     R.ElementType = matAddress.getElementType();
 499     R.VectorIdx = Idx;
 500     R.IsKnownNonNull = matAddress.isKnownNonNull();
 501     R.Initialize(type, type.getQualifiers(), matAddress.getAlignment(),
 502                  BaseInfo, TBAAInfo);
 503     return R;
 504   }
 505
 506   RValue asAggregateRValue(CodeGenFunction &CGF) const {
 507     return RValue::getAggregate(getAddress(CGF), isVolatileQualified());
 508   }
 509 };
 510
 511 /// An aggregate value slot.
 512 class AggValueSlot {
 513   /// The address.
 514   Address Addr;
 515
 516   // Qualifiers
 517   Qualifiers Quals;
 518
 519   /// DestructedFlag - This is set to true if some external code is
 520   /// responsible for setting up a destructor for the slot.  Otherwise
 521   /// the code which constructs it should push the appropriate cleanup.
 522   bool DestructedFlag : 1;
 523
 524   /// ObjCGCFlag - This is set to true if writing to the memory in the
 525   /// slot might require calling an appropriate Objective-C GC
 526   /// barrier.  The exact interaction here is unnecessarily mysterious.
 527   bool ObjCGCFlag : 1;
 528
 529   /// ZeroedFlag - This is set to true if the memory in the slot is
 530   /// known to be zero before the assignment into it.  This means that
 531   /// zero fields don't need to be set.
 532   bool ZeroedFlag : 1;
 533
 534   /// AliasedFlag - This is set to true if the slot might be aliased
 535   /// and it's not undefined behavior to access it through such an
 536   /// alias.  Note that it's always undefined behavior to access a C++
 537   /// object that's under construction through an alias derived from
 538   /// outside the construction process.
 539   ///
 540   /// This flag controls whether calls that produce the aggregate
 541   /// value may be evaluated directly into the slot, or whether they
 542   /// must be evaluated into an unaliased temporary and then memcpy'ed
 543   /// over.  Since it's invalid in general to memcpy a non-POD C++
 544   /// object, it's important that this flag never be set when
 545   /// evaluating an expression which constructs such an object.
 546   bool AliasedFlag : 1;
 547
 548   /// This is set to true if the tail padding of this slot might overlap
 549   /// another object that may have already been initialized (and whose
 550   /// value must be preserved by this initialization). If so, we may only
 551   /// store up to the dsize of the type. Otherwise we can widen stores to
 552   /// the size of the type.
 553   bool OverlapFlag : 1;
 554
 555   /// If is set to true, sanitizer checks are already generated for this address
 556   /// or not required. For instance, if this address represents an object
 557   /// created in 'new' expression, sanitizer checks for memory is made as a part
 558   /// of 'operator new' emission and object constructor should not generate
 559   /// them.
 560   bool SanitizerCheckedFlag : 1;
 561
 562   AggValueSlot(Address Addr, Qualifiers Quals, bool DestructedFlag,
 563                bool ObjCGCFlag, bool ZeroedFlag, bool AliasedFlag,
 564                bool OverlapFlag, bool SanitizerCheckedFlag)
 565       : Addr(Addr), Quals(Quals), DestructedFlag(DestructedFlag),
 566         ObjCGCFlag(ObjCGCFlag), ZeroedFlag(ZeroedFlag),
 567         AliasedFlag(AliasedFlag), OverlapFlag(OverlapFlag),
 568         SanitizerCheckedFlag(SanitizerCheckedFlag) {}
 569
 570 public:
 571   enum IsAliased_t { IsNotAliased, IsAliased };
 572   enum IsDestructed_t { IsNotDestructed, IsDestructed };
 573   enum IsZeroed_t { IsNotZeroed, IsZeroed };
 574   enum Overlap_t { DoesNotOverlap, MayOverlap };
 575   enum NeedsGCBarriers_t { DoesNotNeedGCBarriers, NeedsGCBarriers };
 576   enum IsSanitizerChecked_t { IsNotSanitizerChecked, IsSanitizerChecked };
 577
 578   /// ignored - Returns an aggregate value slot indicating that the
 579   /// aggregate value is being ignored.
 580   static AggValueSlot ignored() {
 581     return forAddr(Address::invalid(), Qualifiers(), IsNotDestructed,
 582                    DoesNotNeedGCBarriers, IsNotAliased, DoesNotOverlap);
 583   }
 584
 585   /// forAddr - Make a slot for an aggregate value.
 586   ///
 587   /// \param quals - The qualifiers that dictate how the slot should
 588   /// be initialied. Only 'volatile' and the Objective-C lifetime
 589   /// qualifiers matter.
 590   ///
 591   /// \param isDestructed - true if something else is responsible
 592   ///   for calling destructors on this object
 593   /// \param needsGC - true if the slot is potentially located
 594   ///   somewhere that ObjC GC calls should be emitted for
 595   static AggValueSlot forAddr(Address addr,
 596                               Qualifiers quals,
 597                               IsDestructed_t isDestructed,
 598                               NeedsGCBarriers_t needsGC,
 599                               IsAliased_t isAliased,
 600                               Overlap_t mayOverlap,
 601                               IsZeroed_t isZeroed = IsNotZeroed,
 602                        IsSanitizerChecked_t isChecked = IsNotSanitizerChecked) {
 603     if (addr.isValid())
 604       addr.setKnownNonNull();
 605     return AggValueSlot(addr, quals, isDestructed, needsGC, isZeroed, isAliased,
 606                         mayOverlap, isChecked);
 607   }
 608
 609   static AggValueSlot
 610   forLValue(const LValue &LV, CodeGenFunction &CGF, IsDestructed_t isDestructed,
 611             NeedsGCBarriers_t needsGC, IsAliased_t isAliased,
 612             Overlap_t mayOverlap, IsZeroed_t isZeroed = IsNotZeroed,
 613             IsSanitizerChecked_t isChecked = IsNotSanitizerChecked) {
 614     return forAddr(LV.getAddress(CGF), LV.getQuals(), isDestructed, needsGC,
 615                    isAliased, mayOverlap, isZeroed, isChecked);
 616   }
 617
 618   IsDestructed_t isExternallyDestructed() const {
 619     return IsDestructed_t(DestructedFlag);
 620   }
 621   void setExternallyDestructed(bool destructed = true) {
 622     DestructedFlag = destructed;
 623   }
 624
 625   Qualifiers getQualifiers() const { return Quals; }
 626
 627   bool isVolatile() const {
 628     return Quals.hasVolatile();
 629   }
 630
 631   void setVolatile(bool flag) {
 632     if (flag)
 633       Quals.addVolatile();
 634     else
 635       Quals.removeVolatile();
 636   }
 637
 638   Qualifiers::ObjCLifetime getObjCLifetime() const {
 639     return Quals.getObjCLifetime();
 640   }
 641
 642   NeedsGCBarriers_t requiresGCollection() const {
 643     return NeedsGCBarriers_t(ObjCGCFlag);
 644   }
 645
 646   llvm::Value *getPointer() const {
 647     return Addr.getPointer();
 648   }
 649
 650   Address getAddress() const {
 651     return Addr;
 652   }
 653
 654   bool isIgnored() const {
 655     return !Addr.isValid();
 656   }
 657
 658   CharUnits getAlignment() const {
 659     return Addr.getAlignment();
 660   }
 661
 662   IsAliased_t isPotentiallyAliased() const {
 663     return IsAliased_t(AliasedFlag);
 664   }
 665
 666   Overlap_t mayOverlap() const {
 667     return Overlap_t(OverlapFlag);
 668   }
 669
 670   bool isSanitizerChecked() const {
 671     return SanitizerCheckedFlag;
 672   }
 673
 674   RValue asRValue() const {
 675     if (isIgnored()) {
 676       return RValue::getIgnored();
 677     } else {
 678       return RValue::getAggregate(getAddress(), isVolatile());
 679     }
 680   }
 681
 682   void setZeroed(bool V = true) { ZeroedFlag = V; }
 683   IsZeroed_t isZeroed() const {
 684     return IsZeroed_t(ZeroedFlag);
 685   }
 686
 687   /// Get the preferred size to use when storing a value to this slot. This
 688   /// is the type size unless that might overlap another object, in which
 689   /// case it's the dsize.
 690   CharUnits getPreferredSize(ASTContext &Ctx, QualType Type) const {
 691     return mayOverlap() ? Ctx.getTypeInfoDataSizeInChars(Type).Width
 692                         : Ctx.getTypeSizeInChars(Type);
 693   }
 694 };
 695
 696 }  // end namespace CodeGen
 697 }  // end namespace clang
 698
 699 #endif