1 //===-- llvm/Metadata.h - Metadata definitions ------------------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
11 /// This file contains the declarations for metadata subclasses.
12 /// They represent the different flavors of metadata that live in LLVM.
14 //===----------------------------------------------------------------------===//
16 #ifndef LLVM_IR_METADATA_H
17 #define LLVM_IR_METADATA_H
19 #include "llvm/ADT/ArrayRef.h"
20 #include "llvm/ADT/DenseMap.h"
21 #include "llvm/ADT/ilist_node.h"
22 #include "llvm/ADT/iterator_range.h"
23 #include "llvm/IR/Constant.h"
24 #include "llvm/IR/MetadataTracking.h"
25 #include "llvm/IR/Value.h"
26 #include "llvm/Support/ErrorHandling.h"
27 #include <type_traits>
32 template<typename ValueSubClass, typename ItemParentClass>
33 class SymbolTableListTraits;
36 enum LLVMConstants : uint32_t {
37 DEBUG_METADATA_VERSION = 2 // Current debug info version number.
40 /// \brief Root of the metadata hierarchy.
42 /// This is a root class for typeless data in the IR.
44 friend class ReplaceableMetadataImpl;
47 const unsigned char SubclassID;
50 /// \brief Storage flag for non-uniqued, otherwise unowned, metadata.
51 bool IsDistinctInContext : 1;
52 // TODO: expose remaining bits to subclasses.
54 unsigned short SubclassData16;
55 unsigned SubclassData32;
61 ConstantAsMetadataKind,
68 : SubclassID(ID), IsDistinctInContext(false), SubclassData16(0),
72 /// \brief Store this in a big non-uniqued untyped bucket.
73 bool isStoredDistinctInContext() const { return IsDistinctInContext; }
75 /// \brief Default handling of a changed operand, which asserts.
77 /// If subclasses pass themselves in as owners to a tracking node reference,
78 /// they must provide an implementation of this method.
79 void handleChangedOperand(void *, Metadata *) {
80 llvm_unreachable("Unimplemented in Metadata subclass");
84 unsigned getMetadataID() const { return SubclassID; }
86 /// \brief User-friendly dump.
88 void print(raw_ostream &OS) const;
89 void printAsOperand(raw_ostream &OS, bool PrintType = true,
90 const Module *M = nullptr) const;
93 #define HANDLE_METADATA(CLASS) class CLASS;
94 #include "llvm/IR/Metadata.def"
96 inline raw_ostream &operator<<(raw_ostream &OS, const Metadata &MD) {
101 /// \brief Metadata wrapper in the Value hierarchy.
103 /// A member of the \a Value hierarchy to represent a reference to metadata.
104 /// This allows, e.g., instrinsics to have metadata as operands.
106 /// Notably, this is the only thing in either hierarchy that is allowed to
107 /// reference \a LocalAsMetadata.
108 class MetadataAsValue : public Value {
109 friend class ReplaceableMetadataImpl;
110 friend class LLVMContextImpl;
114 MetadataAsValue(Type *Ty, Metadata *MD);
118 static MetadataAsValue *get(LLVMContext &Context, Metadata *MD);
119 static MetadataAsValue *getIfExists(LLVMContext &Context, Metadata *MD);
120 Metadata *getMetadata() const { return MD; }
122 static bool classof(const Value *V) {
123 return V->getValueID() == MetadataAsValueVal;
127 void handleChangedMetadata(Metadata *MD);
132 /// \brief Shared implementation of use-lists for replaceable metadata.
134 /// Most metadata cannot be RAUW'ed. This is a shared implementation of
135 /// use-lists and associated API for the two that support it (\a ValueAsMetadata
136 /// and \a TempMDNode).
137 class ReplaceableMetadataImpl {
138 friend class MetadataTracking;
141 typedef MetadataTracking::OwnerTy OwnerTy;
145 SmallDenseMap<void *, std::pair<OwnerTy, uint64_t>, 4> UseMap;
148 ReplaceableMetadataImpl() : NextIndex(0) {}
149 ~ReplaceableMetadataImpl() {
150 assert(UseMap.empty() && "Cannot destroy in-use replaceable metadata");
153 /// \brief Replace all uses of this with MD.
155 /// Replace all uses of this with \c MD, which is allowed to be null.
156 void replaceAllUsesWith(Metadata *MD);
158 /// \brief Resolve all uses of this.
160 /// Resolve all uses of this, turning off RAUW permanently. If \c
161 /// ResolveUsers, call \a GenericMDNode::resolve() on any users whose last
162 /// operand is resolved.
163 void resolveAllUses(bool ResolveUsers = true);
166 void addRef(void *Ref, OwnerTy Owner);
167 void dropRef(void *Ref);
168 void moveRef(void *Ref, void *New, const Metadata &MD);
170 static ReplaceableMetadataImpl *get(Metadata &MD);
173 /// \brief Value wrapper in the Metadata hierarchy.
175 /// This is a custom value handle that allows other metadata to refer to
176 /// classes in the Value hierarchy.
178 /// Because of full uniquing support, each value is only wrapped by a single \a
179 /// ValueAsMetadata object, so the lookup maps are far more efficient than
180 /// those using ValueHandleBase.
181 class ValueAsMetadata : public Metadata, ReplaceableMetadataImpl {
182 friend class ReplaceableMetadataImpl;
183 friend class LLVMContextImpl;
188 ValueAsMetadata(LLVMContext &Context, unsigned ID, Value *V)
189 : Metadata(ID), V(V) {
190 assert(V && "Expected valid value");
192 ~ValueAsMetadata() {}
195 static ValueAsMetadata *get(Value *V);
196 static ConstantAsMetadata *getConstant(Value *C) {
197 return cast<ConstantAsMetadata>(get(C));
199 static LocalAsMetadata *getLocal(Value *Local) {
200 return cast<LocalAsMetadata>(get(Local));
203 static ValueAsMetadata *getIfExists(Value *V);
204 static ConstantAsMetadata *getConstantIfExists(Value *C) {
205 return cast_or_null<ConstantAsMetadata>(getIfExists(C));
207 static LocalAsMetadata *getLocalIfExists(Value *Local) {
208 return cast_or_null<LocalAsMetadata>(getIfExists(Local));
211 Value *getValue() const { return V; }
212 Type *getType() const { return V->getType(); }
213 LLVMContext &getContext() const { return V->getContext(); }
215 static void handleDeletion(Value *V);
216 static void handleRAUW(Value *From, Value *To);
219 /// \brief Handle collisions after \a Value::replaceAllUsesWith().
221 /// RAUW isn't supported directly for \a ValueAsMetadata, but if the wrapped
222 /// \a Value gets RAUW'ed and the target already exists, this is used to
223 /// merge the two metadata nodes.
224 void replaceAllUsesWith(Metadata *MD) {
225 ReplaceableMetadataImpl::replaceAllUsesWith(MD);
229 static bool classof(const Metadata *MD) {
230 return MD->getMetadataID() == LocalAsMetadataKind ||
231 MD->getMetadataID() == ConstantAsMetadataKind;
235 class ConstantAsMetadata : public ValueAsMetadata {
236 friend class ValueAsMetadata;
238 ConstantAsMetadata(LLVMContext &Context, Constant *C)
239 : ValueAsMetadata(Context, ConstantAsMetadataKind, C) {}
242 static ConstantAsMetadata *get(Constant *C) {
243 return ValueAsMetadata::getConstant(C);
245 static ConstantAsMetadata *getIfExists(Constant *C) {
246 return ValueAsMetadata::getConstantIfExists(C);
249 Constant *getValue() const {
250 return cast<Constant>(ValueAsMetadata::getValue());
253 static bool classof(const Metadata *MD) {
254 return MD->getMetadataID() == ConstantAsMetadataKind;
258 class LocalAsMetadata : public ValueAsMetadata {
259 friend class ValueAsMetadata;
261 LocalAsMetadata(LLVMContext &Context, Value *Local)
262 : ValueAsMetadata(Context, LocalAsMetadataKind, Local) {
263 assert(!isa<Constant>(Local) && "Expected local value");
267 static LocalAsMetadata *get(Value *Local) {
268 return ValueAsMetadata::getLocal(Local);
270 static LocalAsMetadata *getIfExists(Value *Local) {
271 return ValueAsMetadata::getLocalIfExists(Local);
274 static bool classof(const Metadata *MD) {
275 return MD->getMetadataID() == LocalAsMetadataKind;
279 /// \brief Transitional API for extracting constants from Metadata.
281 /// This namespace contains transitional functions for metadata that points to
284 /// In prehistory -- when metadata was a subclass of \a Value -- \a MDNode
285 /// operands could refer to any \a Value. There's was a lot of code like this:
289 /// auto *CI = dyn_cast<ConstantInt>(N->getOperand(2));
292 /// Now that \a Value and \a Metadata are in separate hierarchies, maintaining
293 /// the semantics for \a isa(), \a cast(), \a dyn_cast() (etc.) requires three
294 /// steps: cast in the \a Metadata hierarchy, extraction of the \a Value, and
295 /// cast in the \a Value hierarchy. Besides creating boiler-plate, this
296 /// requires subtle control flow changes.
298 /// The end-goal is to create a new type of metadata, called (e.g.) \a MDInt,
299 /// so that metadata can refer to numbers without traversing a bridge to the \a
300 /// Value hierarchy. In this final state, the code above would look like this:
304 /// auto *MI = dyn_cast<MDInt>(N->getOperand(2));
307 /// The API in this namespace supports the transition. \a MDInt doesn't exist
308 /// yet, and even once it does, changing each metadata schema to use it is its
309 /// own mini-project. In the meantime this API prevents us from introducing
310 /// complex and bug-prone control flow that will disappear in the end. In
311 /// particular, the above code looks like this:
315 /// auto *CI = mdconst::dyn_extract<ConstantInt>(N->getOperand(2));
318 /// The full set of provided functions includes:
320 /// mdconst::hasa <=> isa
321 /// mdconst::extract <=> cast
322 /// mdconst::extract_or_null <=> cast_or_null
323 /// mdconst::dyn_extract <=> dyn_cast
324 /// mdconst::dyn_extract_or_null <=> dyn_cast_or_null
326 /// The target of the cast must be a subclass of \a Constant.
330 template <class T> T &make();
331 template <class T, class Result> struct HasDereference {
334 template <size_t N> struct SFINAE {};
336 template <class U, class V>
337 static Yes &hasDereference(SFINAE<sizeof(static_cast<V>(*make<U>()))> * = 0);
338 template <class U, class V> static No &hasDereference(...);
340 static const bool value =
341 sizeof(hasDereference<T, Result>(nullptr)) == sizeof(Yes);
343 template <class V, class M> struct IsValidPointer {
344 static const bool value = std::is_base_of<Constant, V>::value &&
345 HasDereference<M, const Metadata &>::value;
347 template <class V, class M> struct IsValidReference {
348 static const bool value = std::is_base_of<Constant, V>::value &&
349 std::is_convertible<M, const Metadata &>::value;
351 } // end namespace detail
353 /// \brief Check whether Metadata has a Value.
355 /// As an analogue to \a isa(), check whether \c MD has an \a Value inside of
357 template <class X, class Y>
358 inline typename std::enable_if<detail::IsValidPointer<X, Y>::value, bool>::type
360 assert(MD && "Null pointer sent into hasa");
361 if (auto *V = dyn_cast<ConstantAsMetadata>(MD))
362 return isa<X>(V->getValue());
365 template <class X, class Y>
367 typename std::enable_if<detail::IsValidReference<X, Y &>::value, bool>::type
372 /// \brief Extract a Value from Metadata.
374 /// As an analogue to \a cast(), extract the \a Value subclass \c X from \c MD.
375 template <class X, class Y>
376 inline typename std::enable_if<detail::IsValidPointer<X, Y>::value, X *>::type
378 return cast<X>(cast<ConstantAsMetadata>(MD)->getValue());
380 template <class X, class Y>
382 typename std::enable_if<detail::IsValidReference<X, Y &>::value, X *>::type
387 /// \brief Extract a Value from Metadata, allowing null.
389 /// As an analogue to \a cast_or_null(), extract the \a Value subclass \c X
390 /// from \c MD, allowing \c MD to be null.
391 template <class X, class Y>
392 inline typename std::enable_if<detail::IsValidPointer<X, Y>::value, X *>::type
393 extract_or_null(Y &&MD) {
394 if (auto *V = cast_or_null<ConstantAsMetadata>(MD))
395 return cast<X>(V->getValue());
399 /// \brief Extract a Value from Metadata, if any.
401 /// As an analogue to \a dyn_cast_or_null(), extract the \a Value subclass \c X
402 /// from \c MD, return null if \c MD doesn't contain a \a Value or if the \a
403 /// Value it does contain is of the wrong subclass.
404 template <class X, class Y>
405 inline typename std::enable_if<detail::IsValidPointer<X, Y>::value, X *>::type
406 dyn_extract(Y &&MD) {
407 if (auto *V = dyn_cast<ConstantAsMetadata>(MD))
408 return dyn_cast<X>(V->getValue());
412 /// \brief Extract a Value from Metadata, if any, allowing null.
414 /// As an analogue to \a dyn_cast_or_null(), extract the \a Value subclass \c X
415 /// from \c MD, return null if \c MD doesn't contain a \a Value or if the \a
416 /// Value it does contain is of the wrong subclass, allowing \c MD to be null.
417 template <class X, class Y>
418 inline typename std::enable_if<detail::IsValidPointer<X, Y>::value, X *>::type
419 dyn_extract_or_null(Y &&MD) {
420 if (auto *V = dyn_cast_or_null<ConstantAsMetadata>(MD))
421 return dyn_cast<X>(V->getValue());
425 } // end namespace mdconst
427 //===----------------------------------------------------------------------===//
428 /// \brief A single uniqued string.
430 /// These are used to efficiently contain a byte sequence for metadata.
431 /// MDString is always unnamed.
432 class MDString : public Metadata {
433 friend class StringMapEntry<MDString>;
435 MDString(const MDString &) LLVM_DELETED_FUNCTION;
436 MDString &operator=(MDString &&) LLVM_DELETED_FUNCTION;
437 MDString &operator=(const MDString &) LLVM_DELETED_FUNCTION;
439 StringMapEntry<MDString> *Entry;
440 MDString() : Metadata(MDStringKind), Entry(nullptr) {}
441 MDString(MDString &&) : Metadata(MDStringKind) {}
444 static MDString *get(LLVMContext &Context, StringRef Str);
445 static MDString *get(LLVMContext &Context, const char *Str) {
446 return get(Context, Str ? StringRef(Str) : StringRef());
449 StringRef getString() const;
451 unsigned getLength() const { return (unsigned)getString().size(); }
453 typedef StringRef::iterator iterator;
455 /// \brief Pointer to the first byte of the string.
456 iterator begin() const { return getString().begin(); }
458 /// \brief Pointer to one byte past the end of the string.
459 iterator end() const { return getString().end(); }
461 /// \brief Methods for support type inquiry through isa, cast, and dyn_cast.
462 static bool classof(const Metadata *MD) {
463 return MD->getMetadataID() == MDStringKind;
467 /// \brief A collection of metadata nodes that might be associated with a
468 /// memory access used by the alias-analysis infrastructure.
470 explicit AAMDNodes(MDNode *T = nullptr, MDNode *S = nullptr,
472 : TBAA(T), Scope(S), NoAlias(N) {}
474 bool operator==(const AAMDNodes &A) const {
475 return TBAA == A.TBAA && Scope == A.Scope && NoAlias == A.NoAlias;
478 bool operator!=(const AAMDNodes &A) const { return !(*this == A); }
480 LLVM_EXPLICIT operator bool() const { return TBAA || Scope || NoAlias; }
482 /// \brief The tag for type-based alias analysis.
485 /// \brief The tag for alias scope specification (used with noalias).
488 /// \brief The tag specifying the noalias scope.
492 // Specialize DenseMapInfo for AAMDNodes.
494 struct DenseMapInfo<AAMDNodes> {
495 static inline AAMDNodes getEmptyKey() {
496 return AAMDNodes(DenseMapInfo<MDNode *>::getEmptyKey(), 0, 0);
498 static inline AAMDNodes getTombstoneKey() {
499 return AAMDNodes(DenseMapInfo<MDNode *>::getTombstoneKey(), 0, 0);
501 static unsigned getHashValue(const AAMDNodes &Val) {
502 return DenseMapInfo<MDNode *>::getHashValue(Val.TBAA) ^
503 DenseMapInfo<MDNode *>::getHashValue(Val.Scope) ^
504 DenseMapInfo<MDNode *>::getHashValue(Val.NoAlias);
506 static bool isEqual(const AAMDNodes &LHS, const AAMDNodes &RHS) {
511 /// \brief Tracking metadata reference owned by Metadata.
513 /// Similar to \a TrackingMDRef, but it's expected to be owned by an instance
514 /// of \a Metadata, which has the option of registering itself for callbacks to
515 /// re-unique itself.
517 /// In particular, this is used by \a MDNode.
519 MDOperand(MDOperand &&) LLVM_DELETED_FUNCTION;
520 MDOperand(const MDOperand &) LLVM_DELETED_FUNCTION;
521 MDOperand &operator=(MDOperand &&) LLVM_DELETED_FUNCTION;
522 MDOperand &operator=(const MDOperand &) LLVM_DELETED_FUNCTION;
527 MDOperand() : MD(nullptr) {}
528 ~MDOperand() { untrack(); }
530 Metadata *get() const { return MD; }
531 operator Metadata *() const { return get(); }
532 Metadata *operator->() const { return get(); }
533 Metadata &operator*() const { return *get(); }
539 void reset(Metadata *MD, Metadata *Owner) {
546 void track(Metadata *Owner) {
549 MetadataTracking::track(this, *MD, *Owner);
551 MetadataTracking::track(MD);
555 assert(static_cast<void *>(this) == &MD && "Expected same address");
557 MetadataTracking::untrack(MD);
561 template <> struct simplify_type<MDOperand> {
562 typedef Metadata *SimpleType;
563 static SimpleType getSimplifiedValue(MDOperand &MD) { return MD.get(); }
566 template <> struct simplify_type<const MDOperand> {
567 typedef Metadata *SimpleType;
568 static SimpleType getSimplifiedValue(const MDOperand &MD) { return MD.get(); }
571 //===----------------------------------------------------------------------===//
572 /// \brief Tuple of metadata.
573 class MDNode : public Metadata {
574 MDNode(const MDNode &) LLVM_DELETED_FUNCTION;
575 void operator=(const MDNode &) LLVM_DELETED_FUNCTION;
576 void *operator new(size_t) LLVM_DELETED_FUNCTION;
578 LLVMContext &Context;
579 unsigned NumOperands;
582 unsigned MDNodeSubclassData;
584 void *operator new(size_t Size, unsigned NumOps);
586 /// \brief Required by std, but never called.
587 void operator delete(void *Mem);
589 /// \brief Required by std, but never called.
590 void operator delete(void *, unsigned) {
591 llvm_unreachable("Constructor throws?");
594 /// \brief Required by std, but never called.
595 void operator delete(void *, unsigned, bool) {
596 llvm_unreachable("Constructor throws?");
599 MDNode(LLVMContext &Context, unsigned ID, ArrayRef<Metadata *> MDs);
600 ~MDNode() { dropAllReferences(); }
602 void dropAllReferences();
603 void storeDistinctInContext();
605 static MDNode *getMDNode(LLVMContext &C, ArrayRef<Metadata *> MDs,
608 MDOperand *mutable_begin() { return mutable_end() - NumOperands; }
609 MDOperand *mutable_end() { return reinterpret_cast<MDOperand *>(this); }
612 static MDNode *get(LLVMContext &Context, ArrayRef<Metadata *> MDs) {
613 return getMDNode(Context, MDs, true);
615 static MDNode *getWhenValsUnresolved(LLVMContext &Context,
616 ArrayRef<Metadata *> MDs) {
617 // TODO: Remove this.
618 return get(Context, MDs);
621 static MDNode *getIfExists(LLVMContext &Context, ArrayRef<Metadata *> MDs) {
622 return getMDNode(Context, MDs, false);
625 /// \brief Return a temporary MDNode
627 /// For use in constructing cyclic MDNode structures. A temporary MDNode is
628 /// not uniqued, may be RAUW'd, and must be manually deleted with
630 static MDNodeFwdDecl *getTemporary(LLVMContext &Context,
631 ArrayRef<Metadata *> MDs);
633 /// \brief Deallocate a node created by getTemporary.
635 /// The node must not have any users.
636 static void deleteTemporary(MDNode *N);
638 LLVMContext &getContext() const { return Context; }
640 /// \brief Replace a specific operand.
641 void replaceOperandWith(unsigned I, Metadata *New);
643 /// \brief Check if node is fully resolved.
644 bool isResolved() const;
647 /// \brief Set an operand.
649 /// Sets the operand directly, without worrying about uniquing.
650 void setOperand(unsigned I, Metadata *New);
653 typedef const MDOperand *op_iterator;
654 typedef iterator_range<op_iterator> op_range;
656 op_iterator op_begin() const {
657 return const_cast<MDNode *>(this)->mutable_begin();
659 op_iterator op_end() const {
660 return const_cast<MDNode *>(this)->mutable_end();
662 op_range operands() const { return op_range(op_begin(), op_end()); }
664 const MDOperand &getOperand(unsigned I) const {
665 assert(I < NumOperands && "Out of range");
666 return op_begin()[I];
669 /// \brief Return number of MDNode operands.
670 unsigned getNumOperands() const { return NumOperands; }
672 /// \brief Methods for support type inquiry through isa, cast, and dyn_cast:
673 static bool classof(const Metadata *MD) {
674 return MD->getMetadataID() == GenericMDNodeKind ||
675 MD->getMetadataID() == MDNodeFwdDeclKind;
678 /// \brief Check whether MDNode is a vtable access.
679 bool isTBAAVtableAccess() const;
681 /// \brief Methods for metadata merging.
682 static MDNode *concatenate(MDNode *A, MDNode *B);
683 static MDNode *intersect(MDNode *A, MDNode *B);
684 static MDNode *getMostGenericTBAA(MDNode *A, MDNode *B);
685 static AAMDNodes getMostGenericAA(const AAMDNodes &A, const AAMDNodes &B);
686 static MDNode *getMostGenericFPMath(MDNode *A, MDNode *B);
687 static MDNode *getMostGenericRange(MDNode *A, MDNode *B);
690 /// \brief Generic metadata node.
692 /// Generic metadata nodes, with opt-out support for uniquing.
694 /// Although nodes are uniqued by default, \a GenericMDNode has no support for
695 /// RAUW. If an operand change (due to RAUW or otherwise) causes a uniquing
696 /// collision, the uniquing bit is dropped.
698 /// TODO: Make uniquing opt-out (status: mandatory, sometimes dropped).
699 /// TODO: Drop support for RAUW.
700 class GenericMDNode : public MDNode {
701 friend class Metadata;
703 friend class LLVMContextImpl;
704 friend class ReplaceableMetadataImpl;
706 /// \brief Support RAUW as long as one of its arguments is replaceable.
708 /// If an operand is an \a MDNodeFwdDecl (or a replaceable \a GenericMDNode),
709 /// support RAUW to support uniquing as forward declarations are resolved.
710 /// As soon as operands have been resolved, drop support.
712 /// FIXME: Save memory by storing this in a pointer union with the
713 /// LLVMContext, and adding an LLVMContext reference to RMI.
714 std::unique_ptr<ReplaceableMetadataImpl> ReplaceableUses;
716 GenericMDNode(LLVMContext &C, ArrayRef<Metadata *> Vals);
719 void setHash(unsigned Hash) { MDNodeSubclassData = Hash; }
722 /// \brief Get the hash, if any.
723 unsigned getHash() const { return MDNodeSubclassData; }
725 static bool classof(const Metadata *MD) {
726 return MD->getMetadataID() == GenericMDNodeKind;
729 /// \brief Check whether any operands are forward declarations.
731 /// Returns \c true as long as any operands (or their operands, etc.) are \a
734 /// As forward declarations are resolved, their containers should get
735 /// resolved automatically. However, if this (or one of its operands) is
736 /// involved in a cycle, \a resolveCycles() needs to be called explicitly.
737 bool isResolved() const { return !ReplaceableUses; }
739 /// \brief Resolve cycles.
741 /// Once all forward declarations have been resolved, force cycles to be
744 /// \pre No operands (or operands' operands, etc.) are \a MDNodeFwdDecl.
745 void resolveCycles();
748 void handleChangedOperand(void *Ref, Metadata *New);
750 bool hasUnresolvedOperands() const { return SubclassData32; }
751 void incrementUnresolvedOperands() { ++SubclassData32; }
752 void decrementUnresolvedOperands() { --SubclassData32; }
756 /// \brief Forward declaration of metadata.
758 /// Forward declaration of metadata, in the form of a metadata node. Unlike \a
759 /// GenericMDNode, this class has support for RAUW and is suitable for forward
761 class MDNodeFwdDecl : public MDNode, ReplaceableMetadataImpl {
762 friend class Metadata;
764 friend class ReplaceableMetadataImpl;
766 MDNodeFwdDecl(LLVMContext &C, ArrayRef<Metadata *> Vals)
767 : MDNode(C, MDNodeFwdDeclKind, Vals) {}
771 static bool classof(const Metadata *MD) {
772 return MD->getMetadataID() == MDNodeFwdDeclKind;
775 using ReplaceableMetadataImpl::replaceAllUsesWith;
778 //===----------------------------------------------------------------------===//
779 /// \brief A tuple of MDNodes.
781 /// Despite its name, a NamedMDNode isn't itself an MDNode. NamedMDNodes belong
782 /// to modules, have names, and contain lists of MDNodes.
784 /// TODO: Inherit from Metadata.
785 class NamedMDNode : public ilist_node<NamedMDNode> {
786 friend class SymbolTableListTraits<NamedMDNode, Module>;
787 friend struct ilist_traits<NamedMDNode>;
788 friend class LLVMContextImpl;
790 NamedMDNode(const NamedMDNode &) LLVM_DELETED_FUNCTION;
794 void *Operands; // SmallVector<TrackingMDRef, 4>
796 void setParent(Module *M) { Parent = M; }
798 explicit NamedMDNode(const Twine &N);
800 template<class T1, class T2>
801 class op_iterator_impl :
802 public std::iterator<std::bidirectional_iterator_tag, T2> {
803 const NamedMDNode *Node;
805 op_iterator_impl(const NamedMDNode *N, unsigned i) : Node(N), Idx(i) { }
807 friend class NamedMDNode;
810 op_iterator_impl() : Node(nullptr), Idx(0) { }
812 bool operator==(const op_iterator_impl &o) const { return Idx == o.Idx; }
813 bool operator!=(const op_iterator_impl &o) const { return Idx != o.Idx; }
814 op_iterator_impl &operator++() {
818 op_iterator_impl operator++(int) {
819 op_iterator_impl tmp(*this);
823 op_iterator_impl &operator--() {
827 op_iterator_impl operator--(int) {
828 op_iterator_impl tmp(*this);
833 T1 operator*() const { return Node->getOperand(Idx); }
837 /// \brief Drop all references and remove the node from parent module.
838 void eraseFromParent();
840 /// \brief Remove all uses and clear node vector.
841 void dropAllReferences();
845 /// \brief Get the module that holds this named metadata collection.
846 inline Module *getParent() { return Parent; }
847 inline const Module *getParent() const { return Parent; }
849 MDNode *getOperand(unsigned i) const;
850 unsigned getNumOperands() const;
851 void addOperand(MDNode *M);
852 StringRef getName() const;
853 void print(raw_ostream &ROS) const;
856 // ---------------------------------------------------------------------------
857 // Operand Iterator interface...
859 typedef op_iterator_impl<MDNode *, MDNode> op_iterator;
860 op_iterator op_begin() { return op_iterator(this, 0); }
861 op_iterator op_end() { return op_iterator(this, getNumOperands()); }
863 typedef op_iterator_impl<const MDNode *, MDNode> const_op_iterator;
864 const_op_iterator op_begin() const { return const_op_iterator(this, 0); }
865 const_op_iterator op_end() const { return const_op_iterator(this, getNumOperands()); }
867 inline iterator_range<op_iterator> operands() {
868 return iterator_range<op_iterator>(op_begin(), op_end());
870 inline iterator_range<const_op_iterator> operands() const {
871 return iterator_range<const_op_iterator>(op_begin(), op_end());
875 } // end llvm namespace