aboutsummaryrefslogtreecommitdiffstats
path: root/include/llvm/IR/Value.h
blob: 67665bea7c1a5866155df8da9ba788991e81f785 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
//===-- llvm/Value.h - Definition of the Value class ------------*- C++ -*-===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file declares the Value class.
//
//===----------------------------------------------------------------------===//

#ifndef LLVM_IR_VALUE_H
#define LLVM_IR_VALUE_H

#include "llvm-c/Core.h"
#include "llvm/ADT/iterator_range.h"
#include "llvm/IR/Use.h"
#include "llvm/Support/CBindingWrapping.h"
#include "llvm/Support/Casting.h"
#include "llvm/Support/Compiler.h"

namespace llvm {

class APInt;
class Argument;
class AssemblyAnnotationWriter;
class BasicBlock;
class Constant;
class DataLayout;
class Function;
class GlobalAlias;
class GlobalObject;
class GlobalValue;
class GlobalVariable;
class InlineAsm;
class Instruction;
class LLVMContext;
class MDNode;
class Module;
class StringRef;
class Twine;
class Type;
class ValueHandleBase;
class ValueSymbolTable;
class raw_ostream;

template<typename ValueTy> class StringMapEntry;
typedef StringMapEntry<Value*> ValueName;

//===----------------------------------------------------------------------===//
//                                 Value Class
//===----------------------------------------------------------------------===//

/// \brief LLVM Value Representation
///
/// This is a very important LLVM class. It is the base class of all values
/// computed by a program that may be used as operands to other values. Value is
/// the super class of other important classes such as Instruction and Function.
/// All Values have a Type. Type is not a subclass of Value. Some values can
/// have a name and they belong to some Module.  Setting the name on the Value
/// automatically updates the module's symbol table.
///
/// Every value has a "use list" that keeps track of which other Values are
/// using this Value.  A Value can also have an arbitrary number of ValueHandle
/// objects that watch it and listen to RAUW and Destroy events.  See
/// llvm/IR/ValueHandle.h for details.
class Value {
  Type *VTy;
  Use *UseList;

  friend class ValueSymbolTable; // Allow ValueSymbolTable to directly mod Name.
  friend class ValueHandleBase;
  ValueName *Name;

  const unsigned char SubclassID;   // Subclass identifier (for isa/dyn_cast)
  unsigned char HasValueHandle : 1; // Has a ValueHandle pointing to this?
protected:
  /// \brief Hold subclass data that can be dropped.
  ///
  /// This member is similar to SubclassData, however it is for holding
  /// information which may be used to aid optimization, but which may be
  /// cleared to zero without affecting conservative interpretation.
  unsigned char SubclassOptionalData : 7;

private:
  /// \brief Hold arbitrary subclass data.
  ///
  /// This member is defined by this class, but is not used for anything.
  /// Subclasses can use it to hold whatever state they find useful.  This
  /// field is initialized to zero by the ctor.
  unsigned short SubclassData;

protected:
  /// \brief The number of operands in the subclass.
  ///
  /// This member is defined by this class, but not used for anything.
  /// Subclasses can use it to store their number of operands, if they have
  /// any.
  ///
  /// This is stored here to save space in User on 64-bit hosts.  Since most
  /// instances of Value have operands, 32-bit hosts aren't significantly
  /// affected.
  unsigned NumOperands;

private:
  template <typename UseT> // UseT == 'Use' or 'const Use'
  class use_iterator_impl
      : public std::iterator<std::forward_iterator_tag, UseT *, ptrdiff_t> {
    typedef std::iterator<std::forward_iterator_tag, UseT *, ptrdiff_t> super;

    UseT *U;
    explicit use_iterator_impl(UseT *u) : U(u) {}
    friend class Value;

  public:
    typedef typename super::reference reference;
    typedef typename super::pointer pointer;

    use_iterator_impl() : U() {}

    bool operator==(const use_iterator_impl &x) const { return U == x.U; }
    bool operator!=(const use_iterator_impl &x) const { return !operator==(x); }

    use_iterator_impl &operator++() { // Preincrement
      assert(U && "Cannot increment end iterator!");
      U = U->getNext();
      return *this;
    }
    use_iterator_impl operator++(int) { // Postincrement
      auto tmp = *this;
      ++*this;
      return tmp;
    }

    UseT &operator*() const {
      assert(U && "Cannot dereference end iterator!");
      return *U;
    }

    UseT *operator->() const { return &operator*(); }

    operator use_iterator_impl<const UseT>() const {
      return use_iterator_impl<const UseT>(U);
    }
  };

  template <typename UserTy> // UserTy == 'User' or 'const User'
  class user_iterator_impl
      : public std::iterator<std::forward_iterator_tag, UserTy *, ptrdiff_t> {
    typedef std::iterator<std::forward_iterator_tag, UserTy *, ptrdiff_t> super;

    use_iterator_impl<Use> UI;
    explicit user_iterator_impl(Use *U) : UI(U) {}
    friend class Value;

  public:
    typedef typename super::reference reference;
    typedef typename super::pointer pointer;

    user_iterator_impl() {}

    bool operator==(const user_iterator_impl &x) const { return UI == x.UI; }
    bool operator!=(const user_iterator_impl &x) const { return !operator==(x); }

    /// \brief Returns true if this iterator is equal to user_end() on the value.
    bool atEnd() const { return *this == user_iterator_impl(); }

    user_iterator_impl &operator++() { // Preincrement
      ++UI;
      return *this;
    }
    user_iterator_impl operator++(int) { // Postincrement
      auto tmp = *this;
      ++*this;
      return tmp;
    }

    // Retrieve a pointer to the current User.
    UserTy *operator*() const {
      return UI->getUser();
    }

    UserTy *operator->() const { return operator*(); }

    operator user_iterator_impl<const UserTy>() const {
      return user_iterator_impl<const UserTy>(*UI);
    }

    Use &getUse() const { return *UI; }

    /// \brief Return the operand # of this use in its User.
    ///
    /// FIXME: Replace all callers with a direct call to Use::getOperandNo.
    unsigned getOperandNo() const { return UI->getOperandNo(); }
  };

  void operator=(const Value &) LLVM_DELETED_FUNCTION;
  Value(const Value &) LLVM_DELETED_FUNCTION;

protected:
  Value(Type *Ty, unsigned scid);
public:
  virtual ~Value();

  /// \brief Support for debugging, callable in GDB: V->dump()
  void dump() const;

  /// \brief Implement operator<< on Value.
  void print(raw_ostream &O) const;

  /// \brief Print the name of this Value out to the specified raw_ostream.
  ///
  /// This is useful when you just want to print 'int %reg126', not the
  /// instruction that generated it. If you specify a Module for context, then
  /// even constanst get pretty-printed; for example, the type of a null
  /// pointer is printed symbolically.
  void printAsOperand(raw_ostream &O, bool PrintType = true,
                      const Module *M = nullptr) const;

  /// \brief All values are typed, get the type of this value.
  Type *getType() const { return VTy; }

  /// \brief All values hold a context through their type.
  LLVMContext &getContext() const;

  // \brief All values can potentially be named.
  bool hasName() const { return Name != nullptr; }
  ValueName *getValueName() const { return Name; }
  void setValueName(ValueName *VN) { Name = VN; }

  /// \brief Return a constant reference to the value's name.
  ///
  /// This is cheap and guaranteed to return the same reference as long as the
  /// value is not modified.
  StringRef getName() const;

  /// \brief Change the name of the value.
  ///
  /// Choose a new unique name if the provided name is taken.
  ///
  /// \param Name The new name; or "" if the value's name should be removed.
  void setName(const Twine &Name);


  /// \brief Transfer the name from V to this value.
  ///
  /// After taking V's name, sets V's name to empty.
  ///
  /// \note It is an error to call V->takeName(V).
  void takeName(Value *V);

  /// \brief Change all uses of this to point to a new Value.
  ///
  /// Go through the uses list for this definition and make each use point to
  /// "V" instead of "this".  After this completes, 'this's use list is
  /// guaranteed to be empty.
  void replaceAllUsesWith(Value *V);

  //----------------------------------------------------------------------
  // Methods for handling the chain of uses of this Value.
  //
  bool               use_empty() const { return UseList == nullptr; }

  typedef use_iterator_impl<Use>       use_iterator;
  typedef use_iterator_impl<const Use> const_use_iterator;
  use_iterator       use_begin()       { return use_iterator(UseList); }
  const_use_iterator use_begin() const { return const_use_iterator(UseList); }
  use_iterator       use_end()         { return use_iterator();   }
  const_use_iterator use_end()   const { return const_use_iterator();   }
  iterator_range<use_iterator> uses() {
    return iterator_range<use_iterator>(use_begin(), use_end());
  }
  iterator_range<const_use_iterator> uses() const {
    return iterator_range<const_use_iterator>(use_begin(), use_end());
  }

  typedef user_iterator_impl<User>       user_iterator;
  typedef user_iterator_impl<const User> const_user_iterator;
  user_iterator       user_begin()       { return user_iterator(UseList); }
  const_user_iterator user_begin() const { return const_user_iterator(UseList); }
  user_iterator       user_end()         { return user_iterator();   }
  const_user_iterator user_end()   const { return const_user_iterator();   }
  User               *user_back()        { return *user_begin(); }
  const User         *user_back()  const { return *user_begin(); }
  iterator_range<user_iterator> users() {
    return iterator_range<user_iterator>(user_begin(), user_end());
  }
  iterator_range<const_user_iterator> users() const {
    return iterator_range<const_user_iterator>(user_begin(), user_end());
  }

  /// \brief Return true if there is exactly one user of this value.
  ///
  /// This is specialized because it is a common request and does not require
  /// traversing the whole use list.
  bool hasOneUse() const {
    const_use_iterator I = use_begin(), E = use_end();
    if (I == E) return false;
    return ++I == E;
  }

  /// \brief Return true if this Value has exactly N users.
  bool hasNUses(unsigned N) const;

  /// \brief Return true if this value has N users or more.
  ///
  /// This is logically equivalent to getNumUses() >= N.
  bool hasNUsesOrMore(unsigned N) const;

  /// \brief Check if this value is used in the specified basic block.
  bool isUsedInBasicBlock(const BasicBlock *BB) const;

  /// \brief This method computes the number of uses of this Value.
  ///
  /// This is a linear time operation.  Use hasOneUse, hasNUses, or
  /// hasNUsesOrMore to check for specific values.
  unsigned getNumUses() const;

  /// \brief This method should only be used by the Use class.
  void addUse(Use &U) { U.addToList(&UseList); }

  /// \brief Concrete subclass of this.
  ///
  /// An enumeration for keeping track of the concrete subclass of Value that
  /// is actually instantiated. Values of this enumeration are kept in the
  /// Value classes SubclassID field. They are used for concrete type
  /// identification.
  enum ValueTy {
    ArgumentVal,              // This is an instance of Argument
    BasicBlockVal,            // This is an instance of BasicBlock
    FunctionVal,              // This is an instance of Function
    GlobalAliasVal,           // This is an instance of GlobalAlias
    GlobalVariableVal,        // This is an instance of GlobalVariable
    UndefValueVal,            // This is an instance of UndefValue
    BlockAddressVal,          // This is an instance of BlockAddress
    ConstantExprVal,          // This is an instance of ConstantExpr
    ConstantAggregateZeroVal, // This is an instance of ConstantAggregateZero
    ConstantDataArrayVal,     // This is an instance of ConstantDataArray
    ConstantDataVectorVal,    // This is an instance of ConstantDataVector
    ConstantIntVal,           // This is an instance of ConstantInt
    ConstantFPVal,            // This is an instance of ConstantFP
    ConstantArrayVal,         // This is an instance of ConstantArray
    ConstantStructVal,        // This is an instance of ConstantStruct
    ConstantVectorVal,        // This is an instance of ConstantVector
    ConstantPointerNullVal,   // This is an instance of ConstantPointerNull
    GenericMDNodeVal,         // This is an instance of GenericMDNode
    MDNodeFwdDeclVal,         // This is an instance of MDNodeFwdDecl
    MDStringVal,              // This is an instance of MDString
    InlineAsmVal,             // This is an instance of InlineAsm
    InstructionVal,           // This is an instance of Instruction
    // Enum values starting at InstructionVal are used for Instructions;
    // don't add new values here!

    // Markers:
    ConstantFirstVal = FunctionVal,
    ConstantLastVal  = ConstantPointerNullVal
  };

  /// \brief Return an ID for the concrete type of this object.
  ///
  /// This is used to implement the classof checks.  This should not be used
  /// for any other purpose, as the values may change as LLVM evolves.  Also,
  /// note that for instructions, the Instruction's opcode is added to
  /// InstructionVal. So this means three things:
  /// # there is no value with code InstructionVal (no opcode==0).
  /// # there are more possible values for the value type than in ValueTy enum.
  /// # the InstructionVal enumerator must be the highest valued enumerator in
  ///   the ValueTy enum.
  unsigned getValueID() const {
    return SubclassID;
  }

  /// \brief Return the raw optional flags value contained in this value.
  ///
  /// This should only be used when testing two Values for equivalence.
  unsigned getRawSubclassOptionalData() const {
    return SubclassOptionalData;
  }

  /// \brief Clear the optional flags contained in this value.
  void clearSubclassOptionalData() {
    SubclassOptionalData = 0;
  }

  /// \brief Check the optional flags for equality.
  bool hasSameSubclassOptionalData(const Value *V) const {
    return SubclassOptionalData == V->SubclassOptionalData;
  }

  /// \brief Clear any optional flags not set in the given Value.
  void intersectOptionalDataWith(const Value *V) {
    SubclassOptionalData &= V->SubclassOptionalData;
  }

  /// \brief Return true if there is a value handle associated with this value.
  bool hasValueHandle() const { return HasValueHandle; }

  /// \brief Strip off pointer casts, all-zero GEPs, and aliases.
  ///
  /// Returns the original uncasted value.  If this is called on a non-pointer
  /// value, it returns 'this'.
  Value *stripPointerCasts();
  const Value *stripPointerCasts() const {
    return const_cast<Value*>(this)->stripPointerCasts();
  }

  /// \brief Strip off pointer casts and all-zero GEPs.
  ///
  /// Returns the original uncasted value.  If this is called on a non-pointer
  /// value, it returns 'this'.
  Value *stripPointerCastsNoFollowAliases();
  const Value *stripPointerCastsNoFollowAliases() const {
    return const_cast<Value*>(this)->stripPointerCastsNoFollowAliases();
  }

  /// \brief Strip off pointer casts and all-constant inbounds GEPs.
  ///
  /// Returns the original pointer value.  If this is called on a non-pointer
  /// value, it returns 'this'.
  Value *stripInBoundsConstantOffsets();
  const Value *stripInBoundsConstantOffsets() const {
    return const_cast<Value*>(this)->stripInBoundsConstantOffsets();
  }

  /// \brief Accumulate offsets from \a stripInBoundsConstantOffsets().
  ///
  /// Stores the resulting constant offset stripped into the APInt provided.
  /// The provided APInt will be extended or truncated as needed to be the
  /// correct bitwidth for an offset of this pointer type.
  ///
  /// If this is called on a non-pointer value, it returns 'this'.
  Value *stripAndAccumulateInBoundsConstantOffsets(const DataLayout &DL,
                                                   APInt &Offset);
  const Value *stripAndAccumulateInBoundsConstantOffsets(const DataLayout &DL,
                                                         APInt &Offset) const {
    return const_cast<Value *>(this)
        ->stripAndAccumulateInBoundsConstantOffsets(DL, Offset);
  }

  /// \brief Strip off pointer casts and inbounds GEPs.
  ///
  /// Returns the original pointer value.  If this is called on a non-pointer
  /// value, it returns 'this'.
  Value *stripInBoundsOffsets();
  const Value *stripInBoundsOffsets() const {
    return const_cast<Value*>(this)->stripInBoundsOffsets();
  }

  /// \brief Check if this is always a dereferenceable pointer.
  ///
  /// Test if this value is always a pointer to allocated and suitably aligned
  /// memory for a simple load or store.
  bool isDereferenceablePointer(const DataLayout *DL = nullptr) const;

  /// \brief Translate PHI node to its predecessor from the given basic block.
  ///
  /// If this value is a PHI node with CurBB as its parent, return the value in
  /// the PHI node corresponding to PredBB.  If not, return ourself.  This is
  /// useful if you want to know the value something has in a predecessor
  /// block.
  Value *DoPHITranslation(const BasicBlock *CurBB, const BasicBlock *PredBB);

  const Value *DoPHITranslation(const BasicBlock *CurBB,
                                const BasicBlock *PredBB) const{
    return const_cast<Value*>(this)->DoPHITranslation(CurBB, PredBB);
  }

  /// \brief The maximum alignment for instructions.
  ///
  /// This is the greatest alignment value supported by load, store, and alloca
  /// instructions, and global values.
  static const unsigned MaximumAlignment = 1u << 29;

  /// \brief Mutate the type of this Value to be of the specified type.
  ///
  /// Note that this is an extremely dangerous operation which can create
  /// completely invalid IR very easily.  It is strongly recommended that you
  /// recreate IR objects with the right types instead of mutating them in
  /// place.
  void mutateType(Type *Ty) {
    VTy = Ty;
  }

  /// \brief Sort the use-list.
  ///
  /// Sorts the Value's use-list by Cmp using a stable mergesort.  Cmp is
  /// expected to compare two \a Use references.
  template <class Compare> void sortUseList(Compare Cmp);

  /// \brief Reverse the use-list.
  void reverseUseList();

private:
  /// \brief Merge two lists together.
  ///
  /// Merges \c L and \c R using \c Cmp.  To enable stable sorts, always pushes
  /// "equal" items from L before items from R.
  ///
  /// \return the first element in the list.
  ///
  /// \note Completely ignores \a Use::Prev (doesn't read, doesn't update).
  template <class Compare>
  static Use *mergeUseLists(Use *L, Use *R, Compare Cmp) {
    Use *Merged;
    mergeUseListsImpl(L, R, &Merged, Cmp);
    return Merged;
  }

  /// \brief Tail-recursive helper for \a mergeUseLists().
  ///
  /// \param[out] Next the first element in the list.
  template <class Compare>
  static void mergeUseListsImpl(Use *L, Use *R, Use **Next, Compare Cmp);

protected:
  unsigned short getSubclassDataFromValue() const { return SubclassData; }
  void setValueSubclassData(unsigned short D) { SubclassData = D; }
};

inline raw_ostream &operator<<(raw_ostream &OS, const Value &V) {
  V.print(OS);
  return OS;
}

void Use::set(Value *V) {
  if (Val) removeFromList();
  Val = V;
  if (V) V->addUse(*this);
}

template <class Compare> void Value::sortUseList(Compare Cmp) {
  if (!UseList || !UseList->Next)
    // No need to sort 0 or 1 uses.
    return;

  // Note: this function completely ignores Prev pointers until the end when
  // they're fixed en masse.

  // Create a binomial vector of sorted lists, visiting uses one at a time and
  // merging lists as necessary.
  const unsigned MaxSlots = 32;
  Use *Slots[MaxSlots];

  // Collect the first use, turning it into a single-item list.
  Use *Next = UseList->Next;
  UseList->Next = nullptr;
  unsigned NumSlots = 1;
  Slots[0] = UseList;

  // Collect all but the last use.
  while (Next->Next) {
    Use *Current = Next;
    Next = Current->Next;

    // Turn Current into a single-item list.
    Current->Next = nullptr;

    // Save Current in the first available slot, merging on collisions.
    unsigned I;
    for (I = 0; I < NumSlots; ++I) {
      if (!Slots[I])
        break;

      // Merge two lists, doubling the size of Current and emptying slot I.
      //
      // Since the uses in Slots[I] originally preceded those in Current, send
      // Slots[I] in as the left parameter to maintain a stable sort.
      Current = mergeUseLists(Slots[I], Current, Cmp);
      Slots[I] = nullptr;
    }
    // Check if this is a new slot.
    if (I == NumSlots) {
      ++NumSlots;
      assert(NumSlots <= MaxSlots && "Use list bigger than 2^32");
    }

    // Found an open slot.
    Slots[I] = Current;
  }

  // Merge all the lists together.
  assert(Next && "Expected one more Use");
  assert(!Next->Next && "Expected only one Use");
  UseList = Next;
  for (unsigned I = 0; I < NumSlots; ++I)
    if (Slots[I])
      // Since the uses in Slots[I] originally preceded those in UseList, send
      // Slots[I] in as the left parameter to maintain a stable sort.
      UseList = mergeUseLists(Slots[I], UseList, Cmp);

  // Fix the Prev pointers.
  for (Use *I = UseList, **Prev = &UseList; I; I = I->Next) {
    I->setPrev(Prev);
    Prev = &I->Next;
  }
}

template <class Compare>
void Value::mergeUseListsImpl(Use *L, Use *R, Use **Next, Compare Cmp) {
  if (!L) {
    *Next = R;
    return;
  }
  if (!R) {
    *Next = L;
    return;
  }
  if (Cmp(*R, *L)) {
    *Next = R;
    mergeUseListsImpl(L, R->Next, &R->Next, Cmp);
    return;
  }
  *Next = L;
  mergeUseListsImpl(L->Next, R, &L->Next, Cmp);
}

// isa - Provide some specializations of isa so that we don't have to include
// the subtype header files to test to see if the value is a subclass...
//
template <> struct isa_impl<Constant, Value> {
  static inline bool doit(const Value &Val) {
    return Val.getValueID() >= Value::ConstantFirstVal &&
      Val.getValueID() <= Value::ConstantLastVal;
  }
};

template <> struct isa_impl<Argument, Value> {
  static inline bool doit (const Value &Val) {
    return Val.getValueID() == Value::ArgumentVal;
  }
};

template <> struct isa_impl<InlineAsm, Value> {
  static inline bool doit(const Value &Val) {
    return Val.getValueID() == Value::InlineAsmVal;
  }
};

template <> struct isa_impl<Instruction, Value> {
  static inline bool doit(const Value &Val) {
    return Val.getValueID() >= Value::InstructionVal;
  }
};

template <> struct isa_impl<BasicBlock, Value> {
  static inline bool doit(const Value &Val) {
    return Val.getValueID() == Value::BasicBlockVal;
  }
};

template <> struct isa_impl<Function, Value> {
  static inline bool doit(const Value &Val) {
    return Val.getValueID() == Value::FunctionVal;
  }
};

template <> struct isa_impl<GlobalVariable, Value> {
  static inline bool doit(const Value &Val) {
    return Val.getValueID() == Value::GlobalVariableVal;
  }
};

template <> struct isa_impl<GlobalAlias, Value> {
  static inline bool doit(const Value &Val) {
    return Val.getValueID() == Value::GlobalAliasVal;
  }
};

template <> struct isa_impl<GlobalValue, Value> {
  static inline bool doit(const Value &Val) {
    return isa<GlobalObject>(Val) || isa<GlobalAlias>(Val);
  }
};

template <> struct isa_impl<GlobalObject, Value> {
  static inline bool doit(const Value &Val) {
    return isa<GlobalVariable>(Val) || isa<Function>(Val);
  }
};

template <> struct isa_impl<MDNode, Value> {
  static inline bool doit(const Value &Val) {
    return Val.getValueID() == Value::GenericMDNodeVal ||
           Val.getValueID() == Value::MDNodeFwdDeclVal;
  }
};

// Value* is only 4-byte aligned.
template<>
class PointerLikeTypeTraits<Value*> {
  typedef Value* PT;
public:
  static inline void *getAsVoidPointer(PT P) { return P; }
  static inline PT getFromVoidPointer(void *P) {
    return static_cast<PT>(P);
  }
  enum { NumLowBitsAvailable = 2 };
};

// Create wrappers for C Binding types (see CBindingWrapping.h).
DEFINE_ISA_CONVERSION_FUNCTIONS(Value, LLVMValueRef)

/* Specialized opaque value conversions.
 */
inline Value **unwrap(LLVMValueRef *Vals) {
  return reinterpret_cast<Value**>(Vals);
}

template<typename T>
inline T **unwrap(LLVMValueRef *Vals, unsigned Length) {
#ifdef DEBUG
  for (LLVMValueRef *I = Vals, *E = Vals + Length; I != E; ++I)
    cast<T>(*I);
#endif
  (void)Length;
  return reinterpret_cast<T**>(Vals);
}

inline LLVMValueRef *wrap(const Value **Vals) {
  return reinterpret_cast<LLVMValueRef*>(const_cast<Value**>(Vals));
}

} // End llvm namespace

#endif