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 //===----------------------------------------------------------------------===//
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/SmallSet.h"
20 #include "llvm/ADT/SmallString.h"
21 #include "llvm/ADT/StringMap.h"
22 #include "llvm/IR/ConstantRange.h"
23 #include "llvm/IR/Instruction.h"
24 #include "llvm/IR/LLVMContext.h"
25 #include "llvm/IR/LeakDetector.h"
26 #include "llvm/IR/Module.h"
27 #include "llvm/IR/ValueHandle.h"
29 using namespace llvm;
31 MetadataAsValue::MetadataAsValue(Type *Ty, Metadata *MD)
32 : Value(Ty, MetadataAsValueVal), MD(MD) {
33 track();
34 }
36 MetadataAsValue::~MetadataAsValue() {
37 getType()->getContext().pImpl->MetadataAsValues.erase(MD);
38 untrack();
39 }
41 /// \brief Canonicalize metadata arguments to intrinsics.
42 ///
43 /// To support bitcode upgrades (and assembly semantic sugar) for \a
44 /// MetadataAsValue, we need to canonicalize certain metadata.
45 ///
46 /// - nullptr is replaced by an empty MDNode.
47 /// - An MDNode with a single null operand is replaced by an empty MDNode.
48 /// - An MDNode whose only operand is a \a ConstantAsMetadata gets skipped.
49 ///
50 /// This maintains readability of bitcode from when metadata was a type of
51 /// value, and these bridges were unnecessary.
52 static Metadata *canonicalizeMetadataForValue(LLVMContext &Context,
53 Metadata *MD) {
54 if (!MD)
55 // !{}
56 return MDNode::get(Context, None);
58 // Return early if this isn't a single-operand MDNode.
59 auto *N = dyn_cast<MDNode>(MD);
60 if (!N || N->getNumOperands() != 1)
61 return MD;
63 if (!N->getOperand(0))
64 // !{}
65 return MDNode::get(Context, None);
67 if (auto *C = dyn_cast<ConstantAsMetadata>(N->getOperand(0)))
68 // Look through the MDNode.
69 return C;
71 return MD;
72 }
74 MetadataAsValue *MetadataAsValue::get(LLVMContext &Context, Metadata *MD) {
75 MD = canonicalizeMetadataForValue(Context, MD);
76 auto *&Entry = Context.pImpl->MetadataAsValues[MD];
77 if (!Entry)
78 Entry = new MetadataAsValue(Type::getMetadataTy(Context), MD);
79 return Entry;
80 }
82 MetadataAsValue *MetadataAsValue::getIfExists(LLVMContext &Context,
83 Metadata *MD) {
84 MD = canonicalizeMetadataForValue(Context, MD);
85 auto &Store = Context.pImpl->MetadataAsValues;
86 auto I = Store.find(MD);
87 return I == Store.end() ? nullptr : I->second;
88 }
90 void MetadataAsValue::handleChangedMetadata(Metadata *MD) {
91 LLVMContext &Context = getContext();
92 MD = canonicalizeMetadataForValue(Context, MD);
93 auto &Store = Context.pImpl->MetadataAsValues;
95 // Stop tracking the old metadata.
96 Store.erase(this->MD);
97 untrack();
98 this->MD = nullptr;
100 // Start tracking MD, or RAUW if necessary.
101 auto *&Entry = Store[MD];
102 if (Entry) {
103 replaceAllUsesWith(Entry);
104 delete this;
105 return;
106 }
108 this->MD = MD;
109 track();
110 Entry = this;
111 }
113 void MetadataAsValue::track() {
114 if (MD)
115 MetadataTracking::track(&MD, *MD, *this);
116 }
118 void MetadataAsValue::untrack() {
119 if (MD)
120 MetadataTracking::untrack(MD);
121 }
123 void ReplaceableMetadataImpl::addRef(void *Ref, OwnerTy Owner) {
124 bool WasInserted =
125 UseMap.insert(std::make_pair(Ref, std::make_pair(Owner, NextIndex)))
126 .second;
127 (void)WasInserted;
128 assert(WasInserted && "Expected to add a reference");
130 ++NextIndex;
131 assert(NextIndex != 0 && "Unexpected overflow");
132 }
134 void ReplaceableMetadataImpl::dropRef(void *Ref) {
135 bool WasErased = UseMap.erase(Ref);
136 (void)WasErased;
137 assert(WasErased && "Expected to drop a reference");
138 }
140 void ReplaceableMetadataImpl::moveRef(void *Ref, void *New,
141 const Metadata &MD) {
142 auto I = UseMap.find(Ref);
143 assert(I != UseMap.end() && "Expected to move a reference");
144 auto OwnerAndIndex = I->second;
145 UseMap.erase(I);
146 bool WasInserted = UseMap.insert(std::make_pair(New, OwnerAndIndex)).second;
147 (void)WasInserted;
148 assert(WasInserted && "Expected to add a reference");
150 // Check that the references are direct if there's no owner.
151 (void)MD;
152 assert((OwnerAndIndex.first || *static_cast<Metadata **>(Ref) == &MD) &&
153 "Reference without owner must be direct");
154 assert((OwnerAndIndex.first || *static_cast<Metadata **>(New) == &MD) &&
155 "Reference without owner must be direct");
156 }
158 void ReplaceableMetadataImpl::replaceAllUsesWith(Metadata *MD) {
159 assert(!(MD && isa<MDNodeFwdDecl>(MD)) && "Expected non-temp node");
161 if (UseMap.empty())
162 return;
164 // Copy out uses since UseMap will get touched below.
165 typedef std::pair<void *, std::pair<OwnerTy, uint64_t>> UseTy;
166 SmallVector<UseTy, 8> Uses(UseMap.begin(), UseMap.end());
167 std::sort(Uses.begin(), Uses.end(), [](const UseTy &L, const UseTy &R) {
168 return L.second.second < R.second.second;
169 });
170 for (const auto &Pair : Uses) {
171 OwnerTy Owner = Pair.second.first;
172 if (!Owner) {
173 // Update unowned tracking references directly.
174 Metadata *&Ref = *static_cast<Metadata **>(Pair.first);
175 Ref = MD;
176 MetadataTracking::track(Ref);
177 UseMap.erase(Pair.first);
178 continue;
179 }
181 // Check for MetadataAsValue.
182 if (Owner.is<MetadataAsValue *>()) {
183 Owner.get<MetadataAsValue *>()->handleChangedMetadata(MD);
184 continue;
185 }
187 // There's a Metadata owner -- dispatch.
188 Metadata *OwnerMD = Owner.get<Metadata *>();
189 switch (OwnerMD->getMetadataID()) {
190 #define HANDLE_METADATA_LEAF(CLASS) \
191 case Metadata::CLASS##Kind: \
192 cast<CLASS>(OwnerMD)->handleChangedOperand(Pair.first, MD); \
193 continue;
194 #include "llvm/IR/Metadata.def"
195 default:
196 llvm_unreachable("Invalid metadata subclass");
197 }
198 }
199 assert(UseMap.empty() && "Expected all uses to be replaced");
200 }
202 void ReplaceableMetadataImpl::resolveAllUses(bool ResolveUsers) {
203 if (UseMap.empty())
204 return;
206 if (!ResolveUsers) {
207 UseMap.clear();
208 return;
209 }
211 // Copy out uses since UseMap could get touched below.
212 typedef std::pair<void *, std::pair<OwnerTy, uint64_t>> UseTy;
213 SmallVector<UseTy, 8> Uses(UseMap.begin(), UseMap.end());
214 std::sort(Uses.begin(), Uses.end(), [](const UseTy &L, const UseTy &R) {
215 return L.second.second < R.second.second;
216 });
217 UseMap.clear();
218 for (const auto &Pair : Uses) {
219 auto Owner = Pair.second.first;
220 if (!Owner)
221 continue;
222 if (Owner.is<MetadataAsValue *>())
223 continue;
225 // Resolve GenericMDNodes that point at this.
226 auto *OwnerMD = dyn_cast<GenericMDNode>(Owner.get<Metadata *>());
227 if (!OwnerMD)
228 continue;
229 if (OwnerMD->isResolved())
230 continue;
231 OwnerMD->decrementUnresolvedOperands();
232 if (!OwnerMD->hasUnresolvedOperands())
233 OwnerMD->resolve();
234 }
235 }
237 static Function *getLocalFunction(Value *V) {
238 assert(V && "Expected value");
239 if (auto *A = dyn_cast<Argument>(V))
240 return A->getParent();
241 if (BasicBlock *BB = cast<Instruction>(V)->getParent())
242 return BB->getParent();
243 return nullptr;
244 }
246 ValueAsMetadata *ValueAsMetadata::get(Value *V) {
247 assert(V && "Unexpected null Value");
249 auto &Context = V->getContext();
250 auto *&Entry = Context.pImpl->ValuesAsMetadata[V];
251 if (!Entry) {
252 assert((isa<Constant>(V) || isa<Argument>(V) || isa<Instruction>(V)) &&
253 "Expected constant or function-local value");
254 assert(!V->NameAndIsUsedByMD.getInt() &&
255 "Expected this to be the only metadata use");
256 V->NameAndIsUsedByMD.setInt(true);
257 if (auto *C = dyn_cast<Constant>(V))
258 Entry = new ConstantAsMetadata(Context, C);
259 else
260 Entry = new LocalAsMetadata(Context, V);
261 }
263 return Entry;
264 }
266 ValueAsMetadata *ValueAsMetadata::getIfExists(Value *V) {
267 assert(V && "Unexpected null Value");
268 return V->getContext().pImpl->ValuesAsMetadata.lookup(V);
269 }
271 void ValueAsMetadata::handleDeletion(Value *V) {
272 assert(V && "Expected valid value");
274 auto &Store = V->getType()->getContext().pImpl->ValuesAsMetadata;
275 auto I = Store.find(V);
276 if (I == Store.end())
277 return;
279 // Remove old entry from the map.
280 ValueAsMetadata *MD = I->second;
281 assert(MD && "Expected valid metadata");
282 assert(MD->getValue() == V && "Expected valid mapping");
283 Store.erase(I);
285 // Delete the metadata.
286 MD->replaceAllUsesWith(nullptr);
287 delete MD;
288 }
290 void ValueAsMetadata::handleRAUW(Value *From, Value *To) {
291 assert(From && "Expected valid value");
292 assert(To && "Expected valid value");
293 assert(From != To && "Expected changed value");
294 assert(From->getType() == To->getType() && "Unexpected type change");
296 LLVMContext &Context = From->getType()->getContext();
297 auto &Store = Context.pImpl->ValuesAsMetadata;
298 auto I = Store.find(From);
299 if (I == Store.end()) {
300 assert(!From->NameAndIsUsedByMD.getInt() &&
301 "Expected From not to be used by metadata");
302 return;
303 }
305 // Remove old entry from the map.
306 assert(From->NameAndIsUsedByMD.getInt() &&
307 "Expected From to be used by metadata");
308 From->NameAndIsUsedByMD.setInt(false);
309 ValueAsMetadata *MD = I->second;
310 assert(MD && "Expected valid metadata");
311 assert(MD->getValue() == From && "Expected valid mapping");
312 Store.erase(I);
314 if (isa<LocalAsMetadata>(MD)) {
315 if (auto *C = dyn_cast<Constant>(To)) {
316 // Local became a constant.
317 MD->replaceAllUsesWith(ConstantAsMetadata::get(C));
318 delete MD;
319 return;
320 }
321 if (getLocalFunction(From) && getLocalFunction(To) &&
322 getLocalFunction(From) != getLocalFunction(To)) {
323 // Function changed.
324 MD->replaceAllUsesWith(nullptr);
325 delete MD;
326 return;
327 }
328 } else if (!isa<Constant>(To)) {
329 // Changed to function-local value.
330 MD->replaceAllUsesWith(nullptr);
331 delete MD;
332 return;
333 }
335 auto *&Entry = Store[To];
336 if (Entry) {
337 // The target already exists.
338 MD->replaceAllUsesWith(Entry);
339 delete MD;
340 return;
341 }
343 // Update MD in place (and update the map entry).
344 assert(!To->NameAndIsUsedByMD.getInt() &&
345 "Expected this to be the only metadata use");
346 To->NameAndIsUsedByMD.setInt(true);
347 MD->V = To;
348 Entry = MD;
349 }
351 //===----------------------------------------------------------------------===//
352 // MDString implementation.
353 //
355 MDString *MDString::get(LLVMContext &Context, StringRef Str) {
356 auto &Store = Context.pImpl->MDStringCache;
357 auto I = Store.find(Str);
358 if (I != Store.end())
359 return &I->second;
361 auto *Entry =
362 StringMapEntry<MDString>::Create(Str, Store.getAllocator(), MDString());
363 bool WasInserted = Store.insert(Entry);
364 (void)WasInserted;
365 assert(WasInserted && "Expected entry to be inserted");
366 Entry->second.Entry = Entry;
367 return &Entry->second;
368 }
370 StringRef MDString::getString() const {
371 assert(Entry && "Expected to find string map entry");
372 return Entry->first();
373 }
375 //===----------------------------------------------------------------------===//
376 // MDNode implementation.
377 //
379 void *MDNode::operator new(size_t Size, unsigned NumOps) {
380 void *Ptr = ::operator new(Size + NumOps * sizeof(MDOperand));
381 MDOperand *O = static_cast<MDOperand *>(Ptr);
382 for (MDOperand *E = O + NumOps; O != E; ++O)
383 (void)new (O) MDOperand;
384 return O;
385 }
387 void MDNode::operator delete(void *Mem) {
388 MDNode *N = static_cast<MDNode *>(Mem);
389 MDOperand *O = static_cast<MDOperand *>(Mem);
390 for (MDOperand *E = O - N->NumOperands; O != E; --O)
391 (O - 1)->~MDOperand();
392 ::operator delete(O);
393 }
395 MDNode::MDNode(LLVMContext &Context, unsigned ID, ArrayRef<Metadata *> MDs)
396 : Metadata(ID), Context(Context), NumOperands(MDs.size()),
397 MDNodeSubclassData(0) {
398 for (unsigned I = 0, E = MDs.size(); I != E; ++I)
399 setOperand(I, MDs[I]);
400 }
402 bool MDNode::isResolved() const {
403 if (isa<MDNodeFwdDecl>(this))
404 return false;
405 return cast<GenericMDNode>(this)->isResolved();
406 }
408 static bool isOperandUnresolved(Metadata *Op) {
409 if (auto *N = dyn_cast_or_null<MDNode>(Op))
410 return !N->isResolved();
411 return false;
412 }
414 GenericMDNode::GenericMDNode(LLVMContext &C, ArrayRef<Metadata *> Vals)
415 : MDNode(C, GenericMDNodeKind, Vals) {
416 // Check whether any operands are unresolved, requiring re-uniquing.
417 for (const auto &Op : operands())
418 if (isOperandUnresolved(Op))
419 incrementUnresolvedOperands();
421 if (hasUnresolvedOperands())
422 ReplaceableUses.reset(new ReplaceableMetadataImpl);
423 }
425 GenericMDNode::~GenericMDNode() {
426 LLVMContextImpl *pImpl = getContext().pImpl;
427 if (isStoredDistinctInContext())
428 pImpl->NonUniquedMDNodes.erase(this);
429 else
430 pImpl->MDNodeSet.erase(this);
431 }
433 void GenericMDNode::resolve() {
434 assert(!isResolved() && "Expected this to be unresolved");
436 // Move the map, so that this immediately looks resolved.
437 auto Uses = std::move(ReplaceableUses);
438 SubclassData32 = 0;
439 assert(isResolved() && "Expected this to be resolved");
441 // Drop RAUW support.
442 Uses->resolveAllUses();
443 }
445 void GenericMDNode::resolveCycles() {
446 if (isResolved())
447 return;
449 // Resolve this node immediately.
450 resolve();
452 // Resolve all operands.
453 for (const auto &Op : operands()) {
454 if (!Op)
455 continue;
456 assert(!isa<MDNodeFwdDecl>(Op) &&
457 "Expected all forward declarations to be resolved");
458 if (auto *N = dyn_cast<GenericMDNode>(Op))
459 if (!N->isResolved())
460 N->resolveCycles();
461 }
462 }
464 void MDNode::dropAllReferences() {
465 for (unsigned I = 0, E = NumOperands; I != E; ++I)
466 setOperand(I, nullptr);
467 if (auto *G = dyn_cast<GenericMDNode>(this))
468 if (!G->isResolved()) {
469 G->ReplaceableUses->resolveAllUses(/* ResolveUsers */ false);
470 G->ReplaceableUses.reset();
471 }
472 }
474 namespace llvm {
475 /// \brief Make MDOperand transparent for hashing.
476 ///
477 /// This overload of an implementation detail of the hashing library makes
478 /// MDOperand hash to the same value as a \a Metadata pointer.
479 ///
480 /// Note that overloading \a hash_value() as follows:
481 ///
482 /// \code
483 /// size_t hash_value(const MDOperand &X) { return hash_value(X.get()); }
484 /// \endcode
485 ///
486 /// does not cause MDOperand to be transparent. In particular, a bare pointer
487 /// doesn't get hashed before it's combined, whereas \a MDOperand would.
488 static const Metadata *get_hashable_data(const MDOperand &X) { return X.get(); }
489 }
491 void GenericMDNode::handleChangedOperand(void *Ref, Metadata *New) {
492 unsigned Op = static_cast<MDOperand *>(Ref) - op_begin();
493 assert(Op < getNumOperands() && "Expected valid operand");
495 if (isStoredDistinctInContext()) {
496 assert(isResolved() && "Expected distinct node to be resolved");
498 // This node is not uniqued. Just set the operand and be done with it.
499 setOperand(Op, New);
500 return;
501 }
502 if (InRAUW) {
503 // We just hit a recursion due to RAUW. Set the operand and move on, since
504 // we're about to be deleted.
505 //
506 // FIXME: Can this cycle really happen?
507 setOperand(Op, New);
508 return;
509 }
511 auto &Store = getContext().pImpl->MDNodeSet;
512 Store.erase(this);
514 Metadata *Old = getOperand(Op);
515 setOperand(Op, New);
517 // Drop uniquing for self-reference cycles or if an operand drops to null.
518 //
519 // FIXME: Stop dropping uniquing when an operand drops to null. The original
520 // motivation was to prevent madness during teardown of LLVMContextImpl, but
521 // dropAllReferences() fixes that problem in a better way. (It's just here
522 // now for better staging of semantic changes.)
523 if (New == this || !New) {
524 storeDistinctInContext();
525 setHash(0);
526 if (!isResolved())
527 resolve();
528 return;
529 }
531 // Re-calculate the hash.
532 setHash(hash_combine_range(op_begin(), op_end()));
533 #ifndef NDEBUG
534 {
535 SmallVector<Metadata *, 8> MDs(op_begin(), op_end());
536 unsigned RawHash = hash_combine_range(MDs.begin(), MDs.end());
537 assert(getHash() == RawHash &&
538 "Expected hash of MDOperand to equal hash of Metadata*");
539 }
540 #endif
542 // Re-unique the node.
543 GenericMDNodeInfo::KeyTy Key(this);
544 auto I = Store.find_as(Key);
545 if (I == Store.end()) {
546 Store.insert(this);
548 if (!isResolved()) {
549 // Check if the last unresolved operand has just been resolved; if so,
550 // resolve this as well.
551 if (isOperandUnresolved(Old))
552 decrementUnresolvedOperands();
553 if (isOperandUnresolved(New))
554 incrementUnresolvedOperands();
555 if (!hasUnresolvedOperands())
556 resolve();
557 }
559 return;
560 }
562 // Collision.
563 if (!isResolved()) {
564 // Still unresolved, so RAUW.
565 InRAUW = true;
566 ReplaceableUses->replaceAllUsesWith(*I);
567 delete this;
568 return;
569 }
571 // Store in non-uniqued form if this node has already been resolved.
572 setHash(0);
573 storeDistinctInContext();
574 }
576 MDNode *MDNode::getMDNode(LLVMContext &Context, ArrayRef<Metadata *> MDs,
577 bool Insert) {
578 auto &Store = Context.pImpl->MDNodeSet;
580 GenericMDNodeInfo::KeyTy Key(MDs);
581 auto I = Store.find_as(Key);
582 if (I != Store.end())
583 return *I;
584 if (!Insert)
585 return nullptr;
587 // Coallocate space for the node and Operands together, then placement new.
588 GenericMDNode *N = new (MDs.size()) GenericMDNode(Context, MDs);
589 N->setHash(Key.Hash);
590 Store.insert(N);
591 return N;
592 }
594 MDNodeFwdDecl *MDNode::getTemporary(LLVMContext &Context,
595 ArrayRef<Metadata *> MDs) {
596 MDNodeFwdDecl *N = new (MDs.size()) MDNodeFwdDecl(Context, MDs);
597 LeakDetector::addGarbageObject(N);
598 return N;
599 }
601 void MDNode::deleteTemporary(MDNode *N) {
602 assert(isa<MDNodeFwdDecl>(N) && "Expected forward declaration");
603 LeakDetector::removeGarbageObject(N);
604 delete cast<MDNodeFwdDecl>(N);
605 }
607 void MDNode::storeDistinctInContext() {
608 assert(!IsDistinctInContext && "Expected newly distinct metadata");
609 IsDistinctInContext = true;
610 auto *G = cast<GenericMDNode>(this);
611 G->setHash(0);
612 getContext().pImpl->NonUniquedMDNodes.insert(G);
613 }
615 // Replace value from this node's operand list.
616 void MDNode::replaceOperandWith(unsigned I, Metadata *New) {
617 if (getOperand(I) == New)
618 return;
620 if (auto *N = dyn_cast<GenericMDNode>(this)) {
621 N->handleChangedOperand(mutable_begin() + I, New);
622 return;
623 }
625 assert(isa<MDNodeFwdDecl>(this) && "Expected an MDNode");
626 setOperand(I, New);
627 }
629 void MDNode::setOperand(unsigned I, Metadata *New) {
630 assert(I < NumOperands);
631 if (isStoredDistinctInContext() || isa<MDNodeFwdDecl>(this))
632 // No need for a callback, this isn't uniqued.
633 mutable_begin()[I].reset(New, nullptr);
634 else
635 mutable_begin()[I].reset(New, this);
636 }
638 /// \brief Get a node, or a self-reference that looks like it.
639 ///
640 /// Special handling for finding self-references, for use by \a
641 /// MDNode::concatenate() and \a MDNode::intersect() to maintain behaviour from
642 /// when self-referencing nodes were still uniqued. If the first operand has
643 /// the same operands as \c Ops, return the first operand instead.
644 static MDNode *getOrSelfReference(LLVMContext &Context,
645 ArrayRef<Metadata *> Ops) {
646 if (!Ops.empty())
647 if (MDNode *N = dyn_cast_or_null<MDNode>(Ops[0]))
648 if (N->getNumOperands() == Ops.size() && N == N->getOperand(0)) {
649 for (unsigned I = 1, E = Ops.size(); I != E; ++I)
650 if (Ops[I] != N->getOperand(I))
651 return MDNode::get(Context, Ops);
652 return N;
653 }
655 return MDNode::get(Context, Ops);
656 }
658 MDNode *MDNode::concatenate(MDNode *A, MDNode *B) {
659 if (!A)
660 return B;
661 if (!B)
662 return A;
664 SmallVector<Metadata *, 4> MDs(A->getNumOperands() + B->getNumOperands());
666 unsigned j = 0;
667 for (unsigned i = 0, ie = A->getNumOperands(); i != ie; ++i)
668 MDs[j++] = A->getOperand(i);
669 for (unsigned i = 0, ie = B->getNumOperands(); i != ie; ++i)
670 MDs[j++] = B->getOperand(i);
672 // FIXME: This preserves long-standing behaviour, but is it really the right
673 // behaviour? Or was that an unintended side-effect of node uniquing?
674 return getOrSelfReference(A->getContext(), MDs);
675 }
677 MDNode *MDNode::intersect(MDNode *A, MDNode *B) {
678 if (!A || !B)
679 return nullptr;
681 SmallVector<Metadata *, 4> MDs;
682 for (unsigned i = 0, ie = A->getNumOperands(); i != ie; ++i) {
683 Metadata *MD = A->getOperand(i);
684 for (unsigned j = 0, je = B->getNumOperands(); j != je; ++j)
685 if (MD == B->getOperand(j)) {
686 MDs.push_back(MD);
687 break;
688 }
689 }
691 // FIXME: This preserves long-standing behaviour, but is it really the right
692 // behaviour? Or was that an unintended side-effect of node uniquing?
693 return getOrSelfReference(A->getContext(), MDs);
694 }
696 MDNode *MDNode::getMostGenericFPMath(MDNode *A, MDNode *B) {
697 if (!A || !B)
698 return nullptr;
700 APFloat AVal = mdconst::extract<ConstantFP>(A->getOperand(0))->getValueAPF();
701 APFloat BVal = mdconst::extract<ConstantFP>(B->getOperand(0))->getValueAPF();
702 if (AVal.compare(BVal) == APFloat::cmpLessThan)
703 return A;
704 return B;
705 }
707 static bool isContiguous(const ConstantRange &A, const ConstantRange &B) {
708 return A.getUpper() == B.getLower() || A.getLower() == B.getUpper();
709 }
711 static bool canBeMerged(const ConstantRange &A, const ConstantRange &B) {
712 return !A.intersectWith(B).isEmptySet() || isContiguous(A, B);
713 }
715 static bool tryMergeRange(SmallVectorImpl<ConstantInt *> &EndPoints,
716 ConstantInt *Low, ConstantInt *High) {
717 ConstantRange NewRange(Low->getValue(), High->getValue());
718 unsigned Size = EndPoints.size();
719 APInt LB = EndPoints[Size - 2]->getValue();
720 APInt LE = EndPoints[Size - 1]->getValue();
721 ConstantRange LastRange(LB, LE);
722 if (canBeMerged(NewRange, LastRange)) {
723 ConstantRange Union = LastRange.unionWith(NewRange);
724 Type *Ty = High->getType();
725 EndPoints[Size - 2] =
726 cast<ConstantInt>(ConstantInt::get(Ty, Union.getLower()));
727 EndPoints[Size - 1] =
728 cast<ConstantInt>(ConstantInt::get(Ty, Union.getUpper()));
729 return true;
730 }
731 return false;
732 }
734 static void addRange(SmallVectorImpl<ConstantInt *> &EndPoints,
735 ConstantInt *Low, ConstantInt *High) {
736 if (!EndPoints.empty())
737 if (tryMergeRange(EndPoints, Low, High))
738 return;
740 EndPoints.push_back(Low);
741 EndPoints.push_back(High);
742 }
744 MDNode *MDNode::getMostGenericRange(MDNode *A, MDNode *B) {
745 // Given two ranges, we want to compute the union of the ranges. This
746 // is slightly complitade by having to combine the intervals and merge
747 // the ones that overlap.
749 if (!A || !B)
750 return nullptr;
752 if (A == B)
753 return A;
755 // First, walk both lists in older of the lower boundary of each interval.
756 // At each step, try to merge the new interval to the last one we adedd.
757 SmallVector<ConstantInt *, 4> EndPoints;
758 int AI = 0;
759 int BI = 0;
760 int AN = A->getNumOperands() / 2;
761 int BN = B->getNumOperands() / 2;
762 while (AI < AN && BI < BN) {
763 ConstantInt *ALow = mdconst::extract<ConstantInt>(A->getOperand(2 * AI));
764 ConstantInt *BLow = mdconst::extract<ConstantInt>(B->getOperand(2 * BI));
766 if (ALow->getValue().slt(BLow->getValue())) {
767 addRange(EndPoints, ALow,
768 mdconst::extract<ConstantInt>(A->getOperand(2 * AI + 1)));
769 ++AI;
770 } else {
771 addRange(EndPoints, BLow,
772 mdconst::extract<ConstantInt>(B->getOperand(2 * BI + 1)));
773 ++BI;
774 }
775 }
776 while (AI < AN) {
777 addRange(EndPoints, mdconst::extract<ConstantInt>(A->getOperand(2 * AI)),
778 mdconst::extract<ConstantInt>(A->getOperand(2 * AI + 1)));
779 ++AI;
780 }
781 while (BI < BN) {
782 addRange(EndPoints, mdconst::extract<ConstantInt>(B->getOperand(2 * BI)),
783 mdconst::extract<ConstantInt>(B->getOperand(2 * BI + 1)));
784 ++BI;
785 }
787 // If we have more than 2 ranges (4 endpoints) we have to try to merge
788 // the last and first ones.
789 unsigned Size = EndPoints.size();
790 if (Size > 4) {
791 ConstantInt *FB = EndPoints[0];
792 ConstantInt *FE = EndPoints[1];
793 if (tryMergeRange(EndPoints, FB, FE)) {
794 for (unsigned i = 0; i < Size - 2; ++i) {
795 EndPoints[i] = EndPoints[i + 2];
796 }
797 EndPoints.resize(Size - 2);
798 }
799 }
801 // If in the end we have a single range, it is possible that it is now the
802 // full range. Just drop the metadata in that case.
803 if (EndPoints.size() == 2) {
804 ConstantRange Range(EndPoints[0]->getValue(), EndPoints[1]->getValue());
805 if (Range.isFullSet())
806 return nullptr;
807 }
809 SmallVector<Metadata *, 4> MDs;
810 MDs.reserve(EndPoints.size());
811 for (auto *I : EndPoints)
812 MDs.push_back(ConstantAsMetadata::get(I));
813 return MDNode::get(A->getContext(), MDs);
814 }
816 //===----------------------------------------------------------------------===//
817 // NamedMDNode implementation.
818 //
820 static SmallVector<TrackingMDRef, 4> &getNMDOps(void *Operands) {
821 return *(SmallVector<TrackingMDRef, 4> *)Operands;
822 }
824 NamedMDNode::NamedMDNode(const Twine &N)
825 : Name(N.str()), Parent(nullptr),
826 Operands(new SmallVector<TrackingMDRef, 4>()) {}
828 NamedMDNode::~NamedMDNode() {
829 dropAllReferences();
830 delete &getNMDOps(Operands);
831 }
833 unsigned NamedMDNode::getNumOperands() const {
834 return (unsigned)getNMDOps(Operands).size();
835 }
837 MDNode *NamedMDNode::getOperand(unsigned i) const {
838 assert(i < getNumOperands() && "Invalid Operand number!");
839 auto *N = getNMDOps(Operands)[i].get();
840 if (N && i > 10000)
841 N->dump();
842 return cast_or_null<MDNode>(N);
843 }
845 void NamedMDNode::addOperand(MDNode *M) { getNMDOps(Operands).emplace_back(M); }
847 void NamedMDNode::eraseFromParent() {
848 getParent()->eraseNamedMetadata(this);
849 }
851 void NamedMDNode::dropAllReferences() {
852 getNMDOps(Operands).clear();
853 }
855 StringRef NamedMDNode::getName() const {
856 return StringRef(Name);
857 }
859 //===----------------------------------------------------------------------===//
860 // Instruction Metadata method implementations.
861 //
863 void Instruction::setMetadata(StringRef Kind, MDNode *Node) {
864 if (!Node && !hasMetadata())
865 return;
866 setMetadata(getContext().getMDKindID(Kind), Node);
867 }
869 MDNode *Instruction::getMetadataImpl(StringRef Kind) const {
870 return getMetadataImpl(getContext().getMDKindID(Kind));
871 }
873 void Instruction::dropUnknownMetadata(ArrayRef<unsigned> KnownIDs) {
874 SmallSet<unsigned, 5> KnownSet;
875 KnownSet.insert(KnownIDs.begin(), KnownIDs.end());
877 // Drop debug if needed
878 if (KnownSet.erase(LLVMContext::MD_dbg))
879 DbgLoc = DebugLoc();
881 if (!hasMetadataHashEntry())
882 return; // Nothing to remove!
884 DenseMap<const Instruction *, LLVMContextImpl::MDMapTy> &MetadataStore =
885 getContext().pImpl->MetadataStore;
887 if (KnownSet.empty()) {
888 // Just drop our entry at the store.
889 MetadataStore.erase(this);
890 setHasMetadataHashEntry(false);
891 return;
892 }
894 LLVMContextImpl::MDMapTy &Info = MetadataStore[this];
895 unsigned I;
896 unsigned E;
897 // Walk the array and drop any metadata we don't know.
898 for (I = 0, E = Info.size(); I != E;) {
899 if (KnownSet.count(Info[I].first)) {
900 ++I;
901 continue;
902 }
904 Info[I] = std::move(Info.back());
905 Info.pop_back();
906 --E;
907 }
908 assert(E == Info.size());
910 if (E == 0) {
911 // Drop our entry at the store.
912 MetadataStore.erase(this);
913 setHasMetadataHashEntry(false);
914 }
915 }
917 /// setMetadata - Set the metadata of of the specified kind to the specified
918 /// node. This updates/replaces metadata if already present, or removes it if
919 /// Node is null.
920 void Instruction::setMetadata(unsigned KindID, MDNode *Node) {
921 if (!Node && !hasMetadata())
922 return;
924 // Handle 'dbg' as a special case since it is not stored in the hash table.
925 if (KindID == LLVMContext::MD_dbg) {
926 DbgLoc = DebugLoc::getFromDILocation(Node);
927 return;
928 }
930 // Handle the case when we're adding/updating metadata on an instruction.
931 if (Node) {
932 LLVMContextImpl::MDMapTy &Info = getContext().pImpl->MetadataStore[this];
933 assert(!Info.empty() == hasMetadataHashEntry() &&
934 "HasMetadata bit is wonked");
935 if (Info.empty()) {
936 setHasMetadataHashEntry(true);
937 } else {
938 // Handle replacement of an existing value.
939 for (auto &P : Info)
940 if (P.first == KindID) {
941 P.second.reset(Node);
942 return;
943 }
944 }
946 // No replacement, just add it to the list.
947 Info.emplace_back(std::piecewise_construct, std::make_tuple(KindID),
948 std::make_tuple(Node));
949 return;
950 }
952 // Otherwise, we're removing metadata from an instruction.
953 assert((hasMetadataHashEntry() ==
954 (getContext().pImpl->MetadataStore.count(this) > 0)) &&
955 "HasMetadata bit out of date!");
956 if (!hasMetadataHashEntry())
957 return; // Nothing to remove!
958 LLVMContextImpl::MDMapTy &Info = getContext().pImpl->MetadataStore[this];
960 // Common case is removing the only entry.
961 if (Info.size() == 1 && Info[0].first == KindID) {
962 getContext().pImpl->MetadataStore.erase(this);
963 setHasMetadataHashEntry(false);
964 return;
965 }
967 // Handle removal of an existing value.
968 for (unsigned i = 0, e = Info.size(); i != e; ++i)
969 if (Info[i].first == KindID) {
970 Info[i] = std::move(Info.back());
971 Info.pop_back();
972 assert(!Info.empty() && "Removing last entry should be handled above");
973 return;
974 }
975 // Otherwise, removing an entry that doesn't exist on the instruction.
976 }
978 void Instruction::setAAMetadata(const AAMDNodes &N) {
979 setMetadata(LLVMContext::MD_tbaa, N.TBAA);
980 setMetadata(LLVMContext::MD_alias_scope, N.Scope);
981 setMetadata(LLVMContext::MD_noalias, N.NoAlias);
982 }
984 MDNode *Instruction::getMetadataImpl(unsigned KindID) const {
985 // Handle 'dbg' as a special case since it is not stored in the hash table.
986 if (KindID == LLVMContext::MD_dbg)
987 return DbgLoc.getAsMDNode();
989 if (!hasMetadataHashEntry()) return nullptr;
991 LLVMContextImpl::MDMapTy &Info = getContext().pImpl->MetadataStore[this];
992 assert(!Info.empty() && "bit out of sync with hash table");
994 for (const auto &I : Info)
995 if (I.first == KindID)
996 return I.second;
997 return nullptr;
998 }
1000 void Instruction::getAllMetadataImpl(
1001 SmallVectorImpl<std::pair<unsigned, MDNode *>> &Result) const {
1002 Result.clear();
1004 // Handle 'dbg' as a special case since it is not stored in the hash table.
1005 if (!DbgLoc.isUnknown()) {
1006 Result.push_back(
1007 std::make_pair((unsigned)LLVMContext::MD_dbg, DbgLoc.getAsMDNode()));
1008 if (!hasMetadataHashEntry()) return;
1009 }
1011 assert(hasMetadataHashEntry() &&
1012 getContext().pImpl->MetadataStore.count(this) &&
1013 "Shouldn't have called this");
1014 const LLVMContextImpl::MDMapTy &Info =
1015 getContext().pImpl->MetadataStore.find(this)->second;
1016 assert(!Info.empty() && "Shouldn't have called this");
1018 Result.reserve(Result.size() + Info.size());
1019 for (auto &I : Info)
1020 Result.push_back(std::make_pair(I.first, cast<MDNode>(I.second.get())));
1022 // Sort the resulting array so it is stable.
1023 if (Result.size() > 1)
1024 array_pod_sort(Result.begin(), Result.end());
1025 }
1027 void Instruction::getAllMetadataOtherThanDebugLocImpl(
1028 SmallVectorImpl<std::pair<unsigned, MDNode *>> &Result) const {
1029 Result.clear();
1030 assert(hasMetadataHashEntry() &&
1031 getContext().pImpl->MetadataStore.count(this) &&
1032 "Shouldn't have called this");
1033 const LLVMContextImpl::MDMapTy &Info =
1034 getContext().pImpl->MetadataStore.find(this)->second;
1035 assert(!Info.empty() && "Shouldn't have called this");
1036 Result.reserve(Result.size() + Info.size());
1037 for (auto &I : Info)
1038 Result.push_back(std::make_pair(I.first, cast<MDNode>(I.second.get())));
1040 // Sort the resulting array so it is stable.
1041 if (Result.size() > 1)
1042 array_pod_sort(Result.begin(), Result.end());
1043 }
1045 /// clearMetadataHashEntries - Clear all hashtable-based metadata from
1046 /// this instruction.
1047 void Instruction::clearMetadataHashEntries() {
1048 assert(hasMetadataHashEntry() && "Caller should check");
1049 getContext().pImpl->MetadataStore.erase(this);
1050 setHasMetadataHashEntry(false);
1051 }