1//===-- Metadata.cpp - Implement Metadata classes -------------------------===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10// This file implements the Metadata classes.
11//
12//===----------------------------------------------------------------------===//
13
14#include "llvm/IR/Metadata.h"
15#include "LLVMContextImpl.h"
16#include "SymbolTableListTraitsImpl.h"
17#include "llvm/ADT/DenseMap.h"
18#include "llvm/ADT/STLExtras.h"
19#include "llvm/ADT/SmallString.h"
20#include "llvm/ADT/StringMap.h"
21#include "llvm/IR/Instruction.h"
22#include "llvm/IR/LLVMContext.h"
23#include "llvm/IR/Module.h"
24#include "llvm/Support/ConstantRange.h"
25#include "llvm/Support/LeakDetector.h"
26#include "llvm/Support/ValueHandle.h"
27using namespace llvm;
28
29//===----------------------------------------------------------------------===//
30// MDString implementation.
31//
32
33void MDString::anchor() { }
34
35MDString::MDString(LLVMContext &C)
36  : Value(Type::getMetadataTy(C), Value::MDStringVal) {}
37
38MDString *MDString::get(LLVMContext &Context, StringRef Str) {
39  LLVMContextImpl *pImpl = Context.pImpl;
40  StringMapEntry<Value*> &Entry =
41    pImpl->MDStringCache.GetOrCreateValue(Str);
42  Value *&S = Entry.getValue();
43  if (!S) S = new MDString(Context);
44  S->setValueName(&Entry);
45  return cast<MDString>(S);
46}
47
48//===----------------------------------------------------------------------===//
49// MDNodeOperand implementation.
50//
51
52// Use CallbackVH to hold MDNode operands.
53namespace llvm {
54class MDNodeOperand : public CallbackVH {
55  MDNode *getParent() {
56    MDNodeOperand *Cur = this;
57
58    while (Cur->getValPtrInt() != 1)
59      --Cur;
60
61    assert(Cur->getValPtrInt() == 1 &&
62           "Couldn't find the beginning of the operand list!");
63    return reinterpret_cast<MDNode*>(Cur) - 1;
64  }
65
66public:
67  MDNodeOperand(Value *V) : CallbackVH(V) {}
68  ~MDNodeOperand() {}
69
70  void set(Value *V) {
71    unsigned IsFirst = this->getValPtrInt();
72    this->setValPtr(V);
73    this->setAsFirstOperand(IsFirst);
74  }
75
76  /// setAsFirstOperand - Accessor method to mark the operand as the first in
77  /// the list.
78  void setAsFirstOperand(unsigned V) { this->setValPtrInt(V); }
79
80  virtual void deleted();
81  virtual void allUsesReplacedWith(Value *NV);
82};
83} // end namespace llvm.
84
85
86void MDNodeOperand::deleted() {
87  getParent()->replaceOperand(this, 0);
88}
89
90void MDNodeOperand::allUsesReplacedWith(Value *NV) {
91  getParent()->replaceOperand(this, NV);
92}
93
94//===----------------------------------------------------------------------===//
95// MDNode implementation.
96//
97
98/// getOperandPtr - Helper function to get the MDNodeOperand's coallocated on
99/// the end of the MDNode.
100static MDNodeOperand *getOperandPtr(MDNode *N, unsigned Op) {
101  // Use <= instead of < to permit a one-past-the-end address.
102  assert(Op <= N->getNumOperands() && "Invalid operand number");
103  return reinterpret_cast<MDNodeOperand*>(N + 1) + Op;
104}
105
106void MDNode::replaceOperandWith(unsigned i, Value *Val) {
107  MDNodeOperand *Op = getOperandPtr(this, i);
108  replaceOperand(Op, Val);
109}
110
111MDNode::MDNode(LLVMContext &C, ArrayRef<Value*> Vals, bool isFunctionLocal)
112: Value(Type::getMetadataTy(C), Value::MDNodeVal) {
113  NumOperands = Vals.size();
114
115  if (isFunctionLocal)
116    setValueSubclassData(getSubclassDataFromValue() | FunctionLocalBit);
117
118  // Initialize the operand list, which is co-allocated on the end of the node.
119  unsigned i = 0;
120  for (MDNodeOperand *Op = getOperandPtr(this, 0), *E = Op+NumOperands;
121       Op != E; ++Op, ++i) {
122    new (Op) MDNodeOperand(Vals[i]);
123
124    // Mark the first MDNodeOperand as being the first in the list of operands.
125    if (i == 0)
126      Op->setAsFirstOperand(1);
127  }
128}
129
130/// ~MDNode - Destroy MDNode.
131MDNode::~MDNode() {
132  assert((getSubclassDataFromValue() & DestroyFlag) != 0 &&
133         "Not being destroyed through destroy()?");
134  LLVMContextImpl *pImpl = getType()->getContext().pImpl;
135  if (isNotUniqued()) {
136    pImpl->NonUniquedMDNodes.erase(this);
137  } else {
138    pImpl->MDNodeSet.RemoveNode(this);
139  }
140
141  // Destroy the operands.
142  for (MDNodeOperand *Op = getOperandPtr(this, 0), *E = Op+NumOperands;
143       Op != E; ++Op)
144    Op->~MDNodeOperand();
145}
146
147static const Function *getFunctionForValue(Value *V) {
148  if (!V) return NULL;
149  if (Instruction *I = dyn_cast<Instruction>(V)) {
150    BasicBlock *BB = I->getParent();
151    return BB ? BB->getParent() : 0;
152  }
153  if (Argument *A = dyn_cast<Argument>(V))
154    return A->getParent();
155  if (BasicBlock *BB = dyn_cast<BasicBlock>(V))
156    return BB->getParent();
157  if (MDNode *MD = dyn_cast<MDNode>(V))
158    return MD->getFunction();
159  return NULL;
160}
161
162#ifndef NDEBUG
163static const Function *assertLocalFunction(const MDNode *N) {
164  if (!N->isFunctionLocal()) return 0;
165
166  // FIXME: This does not handle cyclic function local metadata.
167  const Function *F = 0, *NewF = 0;
168  for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) {
169    if (Value *V = N->getOperand(i)) {
170      if (MDNode *MD = dyn_cast<MDNode>(V))
171        NewF = assertLocalFunction(MD);
172      else
173        NewF = getFunctionForValue(V);
174    }
175    if (F == 0)
176      F = NewF;
177    else
178      assert((NewF == 0 || F == NewF) &&"inconsistent function-local metadata");
179  }
180  return F;
181}
182#endif
183
184// getFunction - If this metadata is function-local and recursively has a
185// function-local operand, return the first such operand's parent function.
186// Otherwise, return null. getFunction() should not be used for performance-
187// critical code because it recursively visits all the MDNode's operands.
188const Function *MDNode::getFunction() const {
189#ifndef NDEBUG
190  return assertLocalFunction(this);
191#else
192  if (!isFunctionLocal()) return NULL;
193  for (unsigned i = 0, e = getNumOperands(); i != e; ++i)
194    if (const Function *F = getFunctionForValue(getOperand(i)))
195      return F;
196  return NULL;
197#endif
198}
199
200// destroy - Delete this node.  Only when there are no uses.
201void MDNode::destroy() {
202  setValueSubclassData(getSubclassDataFromValue() | DestroyFlag);
203  // Placement delete, then free the memory.
204  this->~MDNode();
205  free(this);
206}
207
208/// isFunctionLocalValue - Return true if this is a value that would require a
209/// function-local MDNode.
210static bool isFunctionLocalValue(Value *V) {
211  return isa<Instruction>(V) || isa<Argument>(V) || isa<BasicBlock>(V) ||
212         (isa<MDNode>(V) && cast<MDNode>(V)->isFunctionLocal());
213}
214
215MDNode *MDNode::getMDNode(LLVMContext &Context, ArrayRef<Value*> Vals,
216                          FunctionLocalness FL, bool Insert) {
217  LLVMContextImpl *pImpl = Context.pImpl;
218
219  // Add all the operand pointers. Note that we don't have to add the
220  // isFunctionLocal bit because that's implied by the operands.
221  // Note that if the operands are later nulled out, the node will be
222  // removed from the uniquing map.
223  FoldingSetNodeID ID;
224  for (unsigned i = 0; i != Vals.size(); ++i)
225    ID.AddPointer(Vals[i]);
226
227  void *InsertPoint;
228  MDNode *N = pImpl->MDNodeSet.FindNodeOrInsertPos(ID, InsertPoint);
229
230  if (N || !Insert)
231    return N;
232
233  bool isFunctionLocal = false;
234  switch (FL) {
235  case FL_Unknown:
236    for (unsigned i = 0; i != Vals.size(); ++i) {
237      Value *V = Vals[i];
238      if (!V) continue;
239      if (isFunctionLocalValue(V)) {
240        isFunctionLocal = true;
241        break;
242      }
243    }
244    break;
245  case FL_No:
246    isFunctionLocal = false;
247    break;
248  case FL_Yes:
249    isFunctionLocal = true;
250    break;
251  }
252
253  // Coallocate space for the node and Operands together, then placement new.
254  void *Ptr = malloc(sizeof(MDNode) + Vals.size() * sizeof(MDNodeOperand));
255  N = new (Ptr) MDNode(Context, Vals, isFunctionLocal);
256
257  // Cache the operand hash.
258  N->Hash = ID.ComputeHash();
259
260  // InsertPoint will have been set by the FindNodeOrInsertPos call.
261  pImpl->MDNodeSet.InsertNode(N, InsertPoint);
262
263  return N;
264}
265
266MDNode *MDNode::get(LLVMContext &Context, ArrayRef<Value*> Vals) {
267  return getMDNode(Context, Vals, FL_Unknown);
268}
269
270MDNode *MDNode::getWhenValsUnresolved(LLVMContext &Context,
271                                      ArrayRef<Value*> Vals,
272                                      bool isFunctionLocal) {
273  return getMDNode(Context, Vals, isFunctionLocal ? FL_Yes : FL_No);
274}
275
276MDNode *MDNode::getIfExists(LLVMContext &Context, ArrayRef<Value*> Vals) {
277  return getMDNode(Context, Vals, FL_Unknown, false);
278}
279
280MDNode *MDNode::getTemporary(LLVMContext &Context, ArrayRef<Value*> Vals) {
281  MDNode *N =
282    (MDNode *)malloc(sizeof(MDNode) + Vals.size() * sizeof(MDNodeOperand));
283  N = new (N) MDNode(Context, Vals, FL_No);
284  N->setValueSubclassData(N->getSubclassDataFromValue() |
285                          NotUniquedBit);
286  LeakDetector::addGarbageObject(N);
287  return N;
288}
289
290void MDNode::deleteTemporary(MDNode *N) {
291  assert(N->use_empty() && "Temporary MDNode has uses!");
292  assert(!N->getContext().pImpl->MDNodeSet.RemoveNode(N) &&
293         "Deleting a non-temporary uniqued node!");
294  assert(!N->getContext().pImpl->NonUniquedMDNodes.erase(N) &&
295         "Deleting a non-temporary non-uniqued node!");
296  assert((N->getSubclassDataFromValue() & NotUniquedBit) &&
297         "Temporary MDNode does not have NotUniquedBit set!");
298  assert((N->getSubclassDataFromValue() & DestroyFlag) == 0 &&
299         "Temporary MDNode has DestroyFlag set!");
300  LeakDetector::removeGarbageObject(N);
301  N->destroy();
302}
303
304/// getOperand - Return specified operand.
305Value *MDNode::getOperand(unsigned i) const {
306  assert(i < getNumOperands() && "Invalid operand number");
307  return *getOperandPtr(const_cast<MDNode*>(this), i);
308}
309
310void MDNode::Profile(FoldingSetNodeID &ID) const {
311  // Add all the operand pointers. Note that we don't have to add the
312  // isFunctionLocal bit because that's implied by the operands.
313  // Note that if the operands are later nulled out, the node will be
314  // removed from the uniquing map.
315  for (unsigned i = 0, e = getNumOperands(); i != e; ++i)
316    ID.AddPointer(getOperand(i));
317}
318
319void MDNode::setIsNotUniqued() {
320  setValueSubclassData(getSubclassDataFromValue() | NotUniquedBit);
321  LLVMContextImpl *pImpl = getType()->getContext().pImpl;
322  pImpl->NonUniquedMDNodes.insert(this);
323}
324
325// Replace value from this node's operand list.
326void MDNode::replaceOperand(MDNodeOperand *Op, Value *To) {
327  Value *From = *Op;
328
329  // If is possible that someone did GV->RAUW(inst), replacing a global variable
330  // with an instruction or some other function-local object.  If this is a
331  // non-function-local MDNode, it can't point to a function-local object.
332  // Handle this case by implicitly dropping the MDNode reference to null.
333  // Likewise if the MDNode is function-local but for a different function.
334  if (To && isFunctionLocalValue(To)) {
335    if (!isFunctionLocal())
336      To = 0;
337    else {
338      const Function *F = getFunction();
339      const Function *FV = getFunctionForValue(To);
340      // Metadata can be function-local without having an associated function.
341      // So only consider functions to have changed if non-null.
342      if (F && FV && F != FV)
343        To = 0;
344    }
345  }
346
347  if (From == To)
348    return;
349
350  // Update the operand.
351  Op->set(To);
352
353  // If this node is already not being uniqued (because one of the operands
354  // already went to null), then there is nothing else to do here.
355  if (isNotUniqued()) return;
356
357  LLVMContextImpl *pImpl = getType()->getContext().pImpl;
358
359  // Remove "this" from the context map.  FoldingSet doesn't have to reprofile
360  // this node to remove it, so we don't care what state the operands are in.
361  pImpl->MDNodeSet.RemoveNode(this);
362
363  // If we are dropping an argument to null, we choose to not unique the MDNode
364  // anymore.  This commonly occurs during destruction, and uniquing these
365  // brings little reuse.  Also, this means we don't need to include
366  // isFunctionLocal bits in FoldingSetNodeIDs for MDNodes.
367  if (To == 0) {
368    setIsNotUniqued();
369    return;
370  }
371
372  // Now that the node is out of the folding set, get ready to reinsert it.
373  // First, check to see if another node with the same operands already exists
374  // in the set.  If so, then this node is redundant.
375  FoldingSetNodeID ID;
376  Profile(ID);
377  void *InsertPoint;
378  if (MDNode *N = pImpl->MDNodeSet.FindNodeOrInsertPos(ID, InsertPoint)) {
379    replaceAllUsesWith(N);
380    destroy();
381    return;
382  }
383
384  // Cache the operand hash.
385  Hash = ID.ComputeHash();
386  // InsertPoint will have been set by the FindNodeOrInsertPos call.
387  pImpl->MDNodeSet.InsertNode(this, InsertPoint);
388
389  // If this MDValue was previously function-local but no longer is, clear
390  // its function-local flag.
391  if (isFunctionLocal() && !isFunctionLocalValue(To)) {
392    bool isStillFunctionLocal = false;
393    for (unsigned i = 0, e = getNumOperands(); i != e; ++i) {
394      Value *V = getOperand(i);
395      if (!V) continue;
396      if (isFunctionLocalValue(V)) {
397        isStillFunctionLocal = true;
398        break;
399      }
400    }
401    if (!isStillFunctionLocal)
402      setValueSubclassData(getSubclassDataFromValue() & ~FunctionLocalBit);
403  }
404}
405
406MDNode *MDNode::getMostGenericTBAA(MDNode *A, MDNode *B) {
407  if (!A || !B)
408    return NULL;
409
410  if (A == B)
411    return A;
412
413  SmallVector<MDNode *, 4> PathA;
414  MDNode *T = A;
415  while (T) {
416    PathA.push_back(T);
417    T = T->getNumOperands() >= 2 ? cast_or_null<MDNode>(T->getOperand(1)) : 0;
418  }
419
420  SmallVector<MDNode *, 4> PathB;
421  T = B;
422  while (T) {
423    PathB.push_back(T);
424    T = T->getNumOperands() >= 2 ? cast_or_null<MDNode>(T->getOperand(1)) : 0;
425  }
426
427  int IA = PathA.size() - 1;
428  int IB = PathB.size() - 1;
429
430  MDNode *Ret = 0;
431  while (IA >= 0 && IB >=0) {
432    if (PathA[IA] == PathB[IB])
433      Ret = PathA[IA];
434    else
435      break;
436    --IA;
437    --IB;
438  }
439  return Ret;
440}
441
442MDNode *MDNode::getMostGenericFPMath(MDNode *A, MDNode *B) {
443  if (!A || !B)
444    return NULL;
445
446  APFloat AVal = cast<ConstantFP>(A->getOperand(0))->getValueAPF();
447  APFloat BVal = cast<ConstantFP>(B->getOperand(0))->getValueAPF();
448  if (AVal.compare(BVal) == APFloat::cmpLessThan)
449    return A;
450  return B;
451}
452
453static bool isContiguous(const ConstantRange &A, const ConstantRange &B) {
454  return A.getUpper() == B.getLower() || A.getLower() == B.getUpper();
455}
456
457static bool canBeMerged(const ConstantRange &A, const ConstantRange &B) {
458  return !A.intersectWith(B).isEmptySet() || isContiguous(A, B);
459}
460
461static bool tryMergeRange(SmallVector<Value*, 4> &EndPoints, ConstantInt *Low,
462                          ConstantInt *High) {
463  ConstantRange NewRange(Low->getValue(), High->getValue());
464  unsigned Size = EndPoints.size();
465  APInt LB = cast<ConstantInt>(EndPoints[Size - 2])->getValue();
466  APInt LE = cast<ConstantInt>(EndPoints[Size - 1])->getValue();
467  ConstantRange LastRange(LB, LE);
468  if (canBeMerged(NewRange, LastRange)) {
469    ConstantRange Union = LastRange.unionWith(NewRange);
470    Type *Ty = High->getType();
471    EndPoints[Size - 2] = ConstantInt::get(Ty, Union.getLower());
472    EndPoints[Size - 1] = ConstantInt::get(Ty, Union.getUpper());
473    return true;
474  }
475  return false;
476}
477
478static void addRange(SmallVector<Value*, 4> &EndPoints, ConstantInt *Low,
479                     ConstantInt *High) {
480  if (!EndPoints.empty())
481    if (tryMergeRange(EndPoints, Low, High))
482      return;
483
484  EndPoints.push_back(Low);
485  EndPoints.push_back(High);
486}
487
488MDNode *MDNode::getMostGenericRange(MDNode *A, MDNode *B) {
489  // Given two ranges, we want to compute the union of the ranges. This
490  // is slightly complitade by having to combine the intervals and merge
491  // the ones that overlap.
492
493  if (!A || !B)
494    return NULL;
495
496  if (A == B)
497    return A;
498
499  // First, walk both lists in older of the lower boundary of each interval.
500  // At each step, try to merge the new interval to the last one we adedd.
501  SmallVector<Value*, 4> EndPoints;
502  int AI = 0;
503  int BI = 0;
504  int AN = A->getNumOperands() / 2;
505  int BN = B->getNumOperands() / 2;
506  while (AI < AN && BI < BN) {
507    ConstantInt *ALow = cast<ConstantInt>(A->getOperand(2 * AI));
508    ConstantInt *BLow = cast<ConstantInt>(B->getOperand(2 * BI));
509
510    if (ALow->getValue().slt(BLow->getValue())) {
511      addRange(EndPoints, ALow, cast<ConstantInt>(A->getOperand(2 * AI + 1)));
512      ++AI;
513    } else {
514      addRange(EndPoints, BLow, cast<ConstantInt>(B->getOperand(2 * BI + 1)));
515      ++BI;
516    }
517  }
518  while (AI < AN) {
519    addRange(EndPoints, cast<ConstantInt>(A->getOperand(2 * AI)),
520             cast<ConstantInt>(A->getOperand(2 * AI + 1)));
521    ++AI;
522  }
523  while (BI < BN) {
524    addRange(EndPoints, cast<ConstantInt>(B->getOperand(2 * BI)),
525             cast<ConstantInt>(B->getOperand(2 * BI + 1)));
526    ++BI;
527  }
528
529  // If we have more than 2 ranges (4 endpoints) we have to try to merge
530  // the last and first ones.
531  unsigned Size = EndPoints.size();
532  if (Size > 4) {
533    ConstantInt *FB = cast<ConstantInt>(EndPoints[0]);
534    ConstantInt *FE = cast<ConstantInt>(EndPoints[1]);
535    if (tryMergeRange(EndPoints, FB, FE)) {
536      for (unsigned i = 0; i < Size - 2; ++i) {
537        EndPoints[i] = EndPoints[i + 2];
538      }
539      EndPoints.resize(Size - 2);
540    }
541  }
542
543  // If in the end we have a single range, it is possible that it is now the
544  // full range. Just drop the metadata in that case.
545  if (EndPoints.size() == 2) {
546    ConstantRange Range(cast<ConstantInt>(EndPoints[0])->getValue(),
547                        cast<ConstantInt>(EndPoints[1])->getValue());
548    if (Range.isFullSet())
549      return NULL;
550  }
551
552  return MDNode::get(A->getContext(), EndPoints);
553}
554
555//===----------------------------------------------------------------------===//
556// NamedMDNode implementation.
557//
558
559static SmallVector<TrackingVH<MDNode>, 4> &getNMDOps(void *Operands) {
560  return *(SmallVector<TrackingVH<MDNode>, 4>*)Operands;
561}
562
563NamedMDNode::NamedMDNode(const Twine &N)
564  : Name(N.str()), Parent(0),
565    Operands(new SmallVector<TrackingVH<MDNode>, 4>()) {
566}
567
568NamedMDNode::~NamedMDNode() {
569  dropAllReferences();
570  delete &getNMDOps(Operands);
571}
572
573/// getNumOperands - Return number of NamedMDNode operands.
574unsigned NamedMDNode::getNumOperands() const {
575  return (unsigned)getNMDOps(Operands).size();
576}
577
578/// getOperand - Return specified operand.
579MDNode *NamedMDNode::getOperand(unsigned i) const {
580  assert(i < getNumOperands() && "Invalid Operand number!");
581  return dyn_cast<MDNode>(&*getNMDOps(Operands)[i]);
582}
583
584/// addOperand - Add metadata Operand.
585void NamedMDNode::addOperand(MDNode *M) {
586  assert(!M->isFunctionLocal() &&
587         "NamedMDNode operands must not be function-local!");
588  getNMDOps(Operands).push_back(TrackingVH<MDNode>(M));
589}
590
591/// eraseFromParent - Drop all references and remove the node from parent
592/// module.
593void NamedMDNode::eraseFromParent() {
594  getParent()->eraseNamedMetadata(this);
595}
596
597/// dropAllReferences - Remove all uses and clear node vector.
598void NamedMDNode::dropAllReferences() {
599  getNMDOps(Operands).clear();
600}
601
602/// getName - Return a constant reference to this named metadata's name.
603StringRef NamedMDNode::getName() const {
604  return StringRef(Name);
605}
606
607//===----------------------------------------------------------------------===//
608// Instruction Metadata method implementations.
609//
610
611void Instruction::setMetadata(StringRef Kind, MDNode *Node) {
612  if (Node == 0 && !hasMetadata()) return;
613  setMetadata(getContext().getMDKindID(Kind), Node);
614}
615
616MDNode *Instruction::getMetadataImpl(StringRef Kind) const {
617  return getMetadataImpl(getContext().getMDKindID(Kind));
618}
619
620/// setMetadata - Set the metadata of of the specified kind to the specified
621/// node.  This updates/replaces metadata if already present, or removes it if
622/// Node is null.
623void Instruction::setMetadata(unsigned KindID, MDNode *Node) {
624  if (Node == 0 && !hasMetadata()) return;
625
626  // Handle 'dbg' as a special case since it is not stored in the hash table.
627  if (KindID == LLVMContext::MD_dbg) {
628    DbgLoc = DebugLoc::getFromDILocation(Node);
629    return;
630  }
631
632  // Handle the case when we're adding/updating metadata on an instruction.
633  if (Node) {
634    LLVMContextImpl::MDMapTy &Info = getContext().pImpl->MetadataStore[this];
635    assert(!Info.empty() == hasMetadataHashEntry() &&
636           "HasMetadata bit is wonked");
637    if (Info.empty()) {
638      setHasMetadataHashEntry(true);
639    } else {
640      // Handle replacement of an existing value.
641      for (unsigned i = 0, e = Info.size(); i != e; ++i)
642        if (Info[i].first == KindID) {
643          Info[i].second = Node;
644          return;
645        }
646    }
647
648    // No replacement, just add it to the list.
649    Info.push_back(std::make_pair(KindID, Node));
650    return;
651  }
652
653  // Otherwise, we're removing metadata from an instruction.
654  assert((hasMetadataHashEntry() ==
655          getContext().pImpl->MetadataStore.count(this)) &&
656         "HasMetadata bit out of date!");
657  if (!hasMetadataHashEntry())
658    return;  // Nothing to remove!
659  LLVMContextImpl::MDMapTy &Info = getContext().pImpl->MetadataStore[this];
660
661  // Common case is removing the only entry.
662  if (Info.size() == 1 && Info[0].first == KindID) {
663    getContext().pImpl->MetadataStore.erase(this);
664    setHasMetadataHashEntry(false);
665    return;
666  }
667
668  // Handle removal of an existing value.
669  for (unsigned i = 0, e = Info.size(); i != e; ++i)
670    if (Info[i].first == KindID) {
671      Info[i] = Info.back();
672      Info.pop_back();
673      assert(!Info.empty() && "Removing last entry should be handled above");
674      return;
675    }
676  // Otherwise, removing an entry that doesn't exist on the instruction.
677}
678
679MDNode *Instruction::getMetadataImpl(unsigned KindID) const {
680  // Handle 'dbg' as a special case since it is not stored in the hash table.
681  if (KindID == LLVMContext::MD_dbg)
682    return DbgLoc.getAsMDNode(getContext());
683
684  if (!hasMetadataHashEntry()) return 0;
685
686  LLVMContextImpl::MDMapTy &Info = getContext().pImpl->MetadataStore[this];
687  assert(!Info.empty() && "bit out of sync with hash table");
688
689  for (LLVMContextImpl::MDMapTy::iterator I = Info.begin(), E = Info.end();
690       I != E; ++I)
691    if (I->first == KindID)
692      return I->second;
693  return 0;
694}
695
696void Instruction::getAllMetadataImpl(SmallVectorImpl<std::pair<unsigned,
697                                       MDNode*> > &Result) const {
698  Result.clear();
699
700  // Handle 'dbg' as a special case since it is not stored in the hash table.
701  if (!DbgLoc.isUnknown()) {
702    Result.push_back(std::make_pair((unsigned)LLVMContext::MD_dbg,
703                                    DbgLoc.getAsMDNode(getContext())));
704    if (!hasMetadataHashEntry()) return;
705  }
706
707  assert(hasMetadataHashEntry() &&
708         getContext().pImpl->MetadataStore.count(this) &&
709         "Shouldn't have called this");
710  const LLVMContextImpl::MDMapTy &Info =
711    getContext().pImpl->MetadataStore.find(this)->second;
712  assert(!Info.empty() && "Shouldn't have called this");
713
714  Result.append(Info.begin(), Info.end());
715
716  // Sort the resulting array so it is stable.
717  if (Result.size() > 1)
718    array_pod_sort(Result.begin(), Result.end());
719}
720
721void Instruction::
722getAllMetadataOtherThanDebugLocImpl(SmallVectorImpl<std::pair<unsigned,
723                                    MDNode*> > &Result) const {
724  Result.clear();
725  assert(hasMetadataHashEntry() &&
726         getContext().pImpl->MetadataStore.count(this) &&
727         "Shouldn't have called this");
728  const LLVMContextImpl::MDMapTy &Info =
729    getContext().pImpl->MetadataStore.find(this)->second;
730  assert(!Info.empty() && "Shouldn't have called this");
731  Result.append(Info.begin(), Info.end());
732
733  // Sort the resulting array so it is stable.
734  if (Result.size() > 1)
735    array_pod_sort(Result.begin(), Result.end());
736}
737
738/// clearMetadataHashEntries - Clear all hashtable-based metadata from
739/// this instruction.
740void Instruction::clearMetadataHashEntries() {
741  assert(hasMetadataHashEntry() && "Caller should check");
742  getContext().pImpl->MetadataStore.erase(this);
743  setHasMetadataHashEntry(false);
744}
745
746