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;
53 // TODO: expose remaining bits to subclasses.
55 unsigned short SubclassData16;
56 unsigned SubclassData32;
62 ConstantAsMetadataKind,
69 : SubclassID(ID), IsDistinctInContext(false), InRAUW(false),
70 SubclassData16(0), SubclassData32(0) {}
73 /// \brief Store this in a big non-uniqued untyped bucket.
74 bool isStoredDistinctInContext() const { return IsDistinctInContext; }
76 /// \brief Default handling of a changed operand, which asserts.
78 /// If subclasses pass themselves in as owners to a tracking node reference,
79 /// they must provide an implementation of this method.
80 void handleChangedOperand(void *, Metadata *) {
81 llvm_unreachable("Unimplemented in Metadata subclass");
85 unsigned getMetadataID() const { return SubclassID; }
87 /// \brief User-friendly dump.
89 void print(raw_ostream &OS) const;
90 void printAsOperand(raw_ostream &OS, bool PrintType = true,
91 const Module *M = nullptr) const;
94 #define HANDLE_METADATA(CLASS) class CLASS;
95 #include "llvm/IR/Metadata.def"
97 inline raw_ostream &operator<<(raw_ostream &OS, const Metadata &MD) {
102 /// \brief Metadata wrapper in the Value hierarchy.
104 /// A member of the \a Value hierarchy to represent a reference to metadata.
105 /// This allows, e.g., instrinsics to have metadata as operands.
107 /// Notably, this is the only thing in either hierarchy that is allowed to
108 /// reference \a LocalAsMetadata.
109 class MetadataAsValue : public Value {
110 friend class ReplaceableMetadataImpl;
111 friend class LLVMContextImpl;
115 MetadataAsValue(Type *Ty, Metadata *MD);
119 static MetadataAsValue *get(LLVMContext &Context, Metadata *MD);
120 static MetadataAsValue *getIfExists(LLVMContext &Context, Metadata *MD);
121 Metadata *getMetadata() const { return MD; }
123 static bool classof(const Value *V) {
124 return V->getValueID() == MetadataAsValueVal;
128 void handleChangedMetadata(Metadata *MD);
133 /// \brief Shared implementation of use-lists for replaceable metadata.
135 /// Most metadata cannot be RAUW'ed. This is a shared implementation of
136 /// use-lists and associated API for the two that support it (\a ValueAsMetadata
137 /// and \a TempMDNode).
138 class ReplaceableMetadataImpl {
139 friend class MetadataTracking;
142 typedef MetadataTracking::OwnerTy OwnerTy;
146 SmallDenseMap<void *, std::pair<OwnerTy, uint64_t>, 4> UseMap;
149 ReplaceableMetadataImpl() : NextIndex(0) {}
150 ~ReplaceableMetadataImpl() {
151 assert(UseMap.empty() && "Cannot destroy in-use replaceable metadata");
154 /// \brief Replace all uses of this with MD.
156 /// Replace all uses of this with \c MD, which is allowed to be null.
157 void replaceAllUsesWith(Metadata *MD);
159 /// \brief Resolve all uses of this.
161 /// Resolve all uses of this, turning off RAUW permanently. If \c
162 /// ResolveUsers, call \a GenericMDNode::resolve() on any users whose last
163 /// operand is resolved.
164 void resolveAllUses(bool ResolveUsers = true);
167 void addRef(void *Ref, OwnerTy Owner);
168 void dropRef(void *Ref);
169 void moveRef(void *Ref, void *New, const Metadata &MD);
171 static ReplaceableMetadataImpl *get(Metadata &MD);
174 /// \brief Value wrapper in the Metadata hierarchy.
176 /// This is a custom value handle that allows other metadata to refer to
177 /// classes in the Value hierarchy.
179 /// Because of full uniquing support, each value is only wrapped by a single \a
180 /// ValueAsMetadata object, so the lookup maps are far more efficient than
181 /// those using ValueHandleBase.
182 class ValueAsMetadata : public Metadata, ReplaceableMetadataImpl {
183 friend class ReplaceableMetadataImpl;
184 friend class LLVMContextImpl;
189 ValueAsMetadata(unsigned ID, Value *V)
190 : Metadata(ID), V(V) {
191 assert(V && "Expected valid value");
193 ~ValueAsMetadata() {}
196 static ValueAsMetadata *get(Value *V);
197 static ConstantAsMetadata *getConstant(Value *C) {
198 return cast<ConstantAsMetadata>(get(C));
200 static LocalAsMetadata *getLocal(Value *Local) {
201 return cast<LocalAsMetadata>(get(Local));
204 static ValueAsMetadata *getIfExists(Value *V);
205 static ConstantAsMetadata *getConstantIfExists(Value *C) {
206 return cast_or_null<ConstantAsMetadata>(getIfExists(C));
208 static LocalAsMetadata *getLocalIfExists(Value *Local) {
209 return cast_or_null<LocalAsMetadata>(getIfExists(Local));
212 Value *getValue() const { return V; }
213 Type *getType() const { return V->getType(); }
214 LLVMContext &getContext() const { return V->getContext(); }
216 static void handleDeletion(Value *V);
217 static void handleRAUW(Value *From, Value *To);
220 /// \brief Handle collisions after \a Value::replaceAllUsesWith().
222 /// RAUW isn't supported directly for \a ValueAsMetadata, but if the wrapped
223 /// \a Value gets RAUW'ed and the target already exists, this is used to
224 /// merge the two metadata nodes.
225 void replaceAllUsesWith(Metadata *MD) {
226 ReplaceableMetadataImpl::replaceAllUsesWith(MD);
230 static bool classof(const Metadata *MD) {
231 return MD->getMetadataID() == LocalAsMetadataKind ||
232 MD->getMetadataID() == ConstantAsMetadataKind;
236 class ConstantAsMetadata : public ValueAsMetadata {
237 friend class ValueAsMetadata;
239 ConstantAsMetadata(Constant *C)
240 : ValueAsMetadata(ConstantAsMetadataKind, C) {}
243 static ConstantAsMetadata *get(Constant *C) {
244 return ValueAsMetadata::getConstant(C);
246 static ConstantAsMetadata *getIfExists(Constant *C) {
247 return ValueAsMetadata::getConstantIfExists(C);
250 Constant *getValue() const {
251 return cast<Constant>(ValueAsMetadata::getValue());
254 static bool classof(const Metadata *MD) {
255 return MD->getMetadataID() == ConstantAsMetadataKind;
259 class LocalAsMetadata : public ValueAsMetadata {
260 friend class ValueAsMetadata;
262 LocalAsMetadata(Value *Local)
263 : ValueAsMetadata(LocalAsMetadataKind, Local) {
264 assert(!isa<Constant>(Local) && "Expected local value");
268 static LocalAsMetadata *get(Value *Local) {
269 return ValueAsMetadata::getLocal(Local);
271 static LocalAsMetadata *getIfExists(Value *Local) {
272 return ValueAsMetadata::getLocalIfExists(Local);
275 static bool classof(const Metadata *MD) {
276 return MD->getMetadataID() == LocalAsMetadataKind;
280 /// \brief Transitional API for extracting constants from Metadata.
282 /// This namespace contains transitional functions for metadata that points to
285 /// In prehistory -- when metadata was a subclass of \a Value -- \a MDNode
286 /// operands could refer to any \a Value. There's was a lot of code like this:
290 /// auto *CI = dyn_cast<ConstantInt>(N->getOperand(2));
293 /// Now that \a Value and \a Metadata are in separate hierarchies, maintaining
294 /// the semantics for \a isa(), \a cast(), \a dyn_cast() (etc.) requires three
295 /// steps: cast in the \a Metadata hierarchy, extraction of the \a Value, and
296 /// cast in the \a Value hierarchy. Besides creating boiler-plate, this
297 /// requires subtle control flow changes.
299 /// The end-goal is to create a new type of metadata, called (e.g.) \a MDInt,
300 /// so that metadata can refer to numbers without traversing a bridge to the \a
301 /// Value hierarchy. In this final state, the code above would look like this:
305 /// auto *MI = dyn_cast<MDInt>(N->getOperand(2));
308 /// The API in this namespace supports the transition. \a MDInt doesn't exist
309 /// yet, and even once it does, changing each metadata schema to use it is its
310 /// own mini-project. In the meantime this API prevents us from introducing
311 /// complex and bug-prone control flow that will disappear in the end. In
312 /// particular, the above code looks like this:
316 /// auto *CI = mdconst::dyn_extract<ConstantInt>(N->getOperand(2));
319 /// The full set of provided functions includes:
321 /// mdconst::hasa <=> isa
322 /// mdconst::extract <=> cast
323 /// mdconst::extract_or_null <=> cast_or_null
324 /// mdconst::dyn_extract <=> dyn_cast
325 /// mdconst::dyn_extract_or_null <=> dyn_cast_or_null
327 /// The target of the cast must be a subclass of \a Constant.
331 template <class T> T &make();
332 template <class T, class Result> struct HasDereference {
335 template <size_t N> struct SFINAE {};
337 template <class U, class V>
338 static Yes &hasDereference(SFINAE<sizeof(static_cast<V>(*make<U>()))> * = 0);
339 template <class U, class V> static No &hasDereference(...);
341 static const bool value =
342 sizeof(hasDereference<T, Result>(nullptr)) == sizeof(Yes);
344 template <class V, class M> struct IsValidPointer {
345 static const bool value = std::is_base_of<Constant, V>::value &&
346 HasDereference<M, const Metadata &>::value;
348 template <class V, class M> struct IsValidReference {
349 static const bool value = std::is_base_of<Constant, V>::value &&
350 std::is_convertible<M, const Metadata &>::value;
352 } // end namespace detail
354 /// \brief Check whether Metadata has a Value.
356 /// As an analogue to \a isa(), check whether \c MD has an \a Value inside of
358 template <class X, class Y>
359 inline typename std::enable_if<detail::IsValidPointer<X, Y>::value, bool>::type
361 assert(MD && "Null pointer sent into hasa");
362 if (auto *V = dyn_cast<ConstantAsMetadata>(MD))
363 return isa<X>(V->getValue());
366 template <class X, class Y>
368 typename std::enable_if<detail::IsValidReference<X, Y &>::value, bool>::type
373 /// \brief Extract a Value from Metadata.
375 /// As an analogue to \a cast(), extract the \a Value subclass \c X from \c MD.
376 template <class X, class Y>
377 inline typename std::enable_if<detail::IsValidPointer<X, Y>::value, X *>::type
379 return cast<X>(cast<ConstantAsMetadata>(MD)->getValue());
381 template <class X, class Y>
383 typename std::enable_if<detail::IsValidReference<X, Y &>::value, X *>::type
388 /// \brief Extract a Value from Metadata, allowing null.
390 /// As an analogue to \a cast_or_null(), extract the \a Value subclass \c X
391 /// from \c MD, allowing \c MD to be null.
392 template <class X, class Y>
393 inline typename std::enable_if<detail::IsValidPointer<X, Y>::value, X *>::type
394 extract_or_null(Y &&MD) {
395 if (auto *V = cast_or_null<ConstantAsMetadata>(MD))
396 return cast<X>(V->getValue());
400 /// \brief Extract a Value from Metadata, if any.
402 /// As an analogue to \a dyn_cast_or_null(), extract the \a Value subclass \c X
403 /// from \c MD, return null if \c MD doesn't contain a \a Value or if the \a
404 /// Value it does contain is of the wrong subclass.
405 template <class X, class Y>
406 inline typename std::enable_if<detail::IsValidPointer<X, Y>::value, X *>::type
407 dyn_extract(Y &&MD) {
408 if (auto *V = dyn_cast<ConstantAsMetadata>(MD))
409 return dyn_cast<X>(V->getValue());
413 /// \brief Extract a Value from Metadata, if any, allowing null.
415 /// As an analogue to \a dyn_cast_or_null(), extract the \a Value subclass \c X
416 /// from \c MD, return null if \c MD doesn't contain a \a Value or if the \a
417 /// Value it does contain is of the wrong subclass, allowing \c MD to be null.
418 template <class X, class Y>
419 inline typename std::enable_if<detail::IsValidPointer<X, Y>::value, X *>::type
420 dyn_extract_or_null(Y &&MD) {
421 if (auto *V = dyn_cast_or_null<ConstantAsMetadata>(MD))
422 return dyn_cast<X>(V->getValue());
426 } // end namespace mdconst
428 //===----------------------------------------------------------------------===//
429 /// \brief A single uniqued string.
431 /// These are used to efficiently contain a byte sequence for metadata.
432 /// MDString is always unnamed.
433 class MDString : public Metadata {
434 friend class StringMapEntry<MDString>;
436 MDString(const MDString &) LLVM_DELETED_FUNCTION;
437 MDString &operator=(MDString &&) LLVM_DELETED_FUNCTION;
438 MDString &operator=(const MDString &) LLVM_DELETED_FUNCTION;
440 StringMapEntry<MDString> *Entry;
441 MDString() : Metadata(MDStringKind), Entry(nullptr) {}
442 MDString(MDString &&) : Metadata(MDStringKind) {}
445 static MDString *get(LLVMContext &Context, StringRef Str);
446 static MDString *get(LLVMContext &Context, const char *Str) {
447 return get(Context, Str ? StringRef(Str) : StringRef());
450 StringRef getString() const;
452 unsigned getLength() const { return (unsigned)getString().size(); }
454 typedef StringRef::iterator iterator;
456 /// \brief Pointer to the first byte of the string.
457 iterator begin() const { return getString().begin(); }
459 /// \brief Pointer to one byte past the end of the string.
460 iterator end() const { return getString().end(); }
462 const unsigned char *bytes_begin() const { return getString().bytes_begin(); }
463 const unsigned char *bytes_end() const { return getString().bytes_end(); }
465 /// \brief Methods for support type inquiry through isa, cast, and dyn_cast.
466 static bool classof(const Metadata *MD) {
467 return MD->getMetadataID() == MDStringKind;
471 /// \brief A collection of metadata nodes that might be associated with a
472 /// memory access used by the alias-analysis infrastructure.
474 explicit AAMDNodes(MDNode *T = nullptr, MDNode *S = nullptr,
476 : TBAA(T), Scope(S), NoAlias(N) {}
478 bool operator==(const AAMDNodes &A) const {
479 return TBAA == A.TBAA && Scope == A.Scope && NoAlias == A.NoAlias;
482 bool operator!=(const AAMDNodes &A) const { return !(*this == A); }
484 LLVM_EXPLICIT operator bool() const { return TBAA || Scope || NoAlias; }
486 /// \brief The tag for type-based alias analysis.
489 /// \brief The tag for alias scope specification (used with noalias).
492 /// \brief The tag specifying the noalias scope.
496 // Specialize DenseMapInfo for AAMDNodes.
498 struct DenseMapInfo<AAMDNodes> {
499 static inline AAMDNodes getEmptyKey() {
500 return AAMDNodes(DenseMapInfo<MDNode *>::getEmptyKey(), 0, 0);
502 static inline AAMDNodes getTombstoneKey() {
503 return AAMDNodes(DenseMapInfo<MDNode *>::getTombstoneKey(), 0, 0);
505 static unsigned getHashValue(const AAMDNodes &Val) {
506 return DenseMapInfo<MDNode *>::getHashValue(Val.TBAA) ^
507 DenseMapInfo<MDNode *>::getHashValue(Val.Scope) ^
508 DenseMapInfo<MDNode *>::getHashValue(Val.NoAlias);
510 static bool isEqual(const AAMDNodes &LHS, const AAMDNodes &RHS) {
515 /// \brief Tracking metadata reference owned by Metadata.
517 /// Similar to \a TrackingMDRef, but it's expected to be owned by an instance
518 /// of \a Metadata, which has the option of registering itself for callbacks to
519 /// re-unique itself.
521 /// In particular, this is used by \a MDNode.
523 MDOperand(MDOperand &&) LLVM_DELETED_FUNCTION;
524 MDOperand(const MDOperand &) LLVM_DELETED_FUNCTION;
525 MDOperand &operator=(MDOperand &&) LLVM_DELETED_FUNCTION;
526 MDOperand &operator=(const MDOperand &) LLVM_DELETED_FUNCTION;
531 MDOperand() : MD(nullptr) {}
532 ~MDOperand() { untrack(); }
534 Metadata *get() const { return MD; }
535 operator Metadata *() const { return get(); }
536 Metadata *operator->() const { return get(); }
537 Metadata &operator*() const { return *get(); }
543 void reset(Metadata *MD, Metadata *Owner) {
550 void track(Metadata *Owner) {
553 MetadataTracking::track(this, *MD, *Owner);
555 MetadataTracking::track(MD);
559 assert(static_cast<void *>(this) == &MD && "Expected same address");
561 MetadataTracking::untrack(MD);
565 template <> struct simplify_type<MDOperand> {
566 typedef Metadata *SimpleType;
567 static SimpleType getSimplifiedValue(MDOperand &MD) { return MD.get(); }
570 template <> struct simplify_type<const MDOperand> {
571 typedef Metadata *SimpleType;
572 static SimpleType getSimplifiedValue(const MDOperand &MD) { return MD.get(); }
575 //===----------------------------------------------------------------------===//
576 /// \brief Tuple of metadata.
577 class MDNode : public Metadata {
578 MDNode(const MDNode &) LLVM_DELETED_FUNCTION;
579 void operator=(const MDNode &) LLVM_DELETED_FUNCTION;
580 void *operator new(size_t) LLVM_DELETED_FUNCTION;
582 LLVMContext &Context;
583 unsigned NumOperands;
586 unsigned MDNodeSubclassData;
588 void *operator new(size_t Size, unsigned NumOps);
590 /// \brief Required by std, but never called.
591 void operator delete(void *Mem);
593 /// \brief Required by std, but never called.
594 void operator delete(void *, unsigned) {
595 llvm_unreachable("Constructor throws?");
598 /// \brief Required by std, but never called.
599 void operator delete(void *, unsigned, bool) {
600 llvm_unreachable("Constructor throws?");
603 MDNode(LLVMContext &Context, unsigned ID, ArrayRef<Metadata *> MDs);
606 void dropAllReferences();
607 void storeDistinctInContext();
609 static MDNode *getMDNode(LLVMContext &C, ArrayRef<Metadata *> MDs,
612 MDOperand *mutable_begin() { return mutable_end() - NumOperands; }
613 MDOperand *mutable_end() { return reinterpret_cast<MDOperand *>(this); }
616 static MDNode *get(LLVMContext &Context, ArrayRef<Metadata *> MDs) {
617 return getMDNode(Context, MDs, true);
619 static MDNode *getWhenValsUnresolved(LLVMContext &Context,
620 ArrayRef<Metadata *> MDs) {
621 // TODO: Remove this.
622 return get(Context, MDs);
625 static MDNode *getIfExists(LLVMContext &Context, ArrayRef<Metadata *> MDs) {
626 return getMDNode(Context, MDs, false);
629 /// \brief Return a temporary MDNode
631 /// For use in constructing cyclic MDNode structures. A temporary MDNode is
632 /// not uniqued, may be RAUW'd, and must be manually deleted with
634 static MDNodeFwdDecl *getTemporary(LLVMContext &Context,
635 ArrayRef<Metadata *> MDs);
637 /// \brief Deallocate a node created by getTemporary.
639 /// The node must not have any users.
640 static void deleteTemporary(MDNode *N);
642 LLVMContext &getContext() const { return Context; }
644 /// \brief Replace a specific operand.
645 void replaceOperandWith(unsigned I, Metadata *New);
647 /// \brief Check if node is fully resolved.
648 bool isResolved() const;
651 /// \brief Set an operand.
653 /// Sets the operand directly, without worrying about uniquing.
654 void setOperand(unsigned I, Metadata *New);
657 typedef const MDOperand *op_iterator;
658 typedef iterator_range<op_iterator> op_range;
660 op_iterator op_begin() const {
661 return const_cast<MDNode *>(this)->mutable_begin();
663 op_iterator op_end() const {
664 return const_cast<MDNode *>(this)->mutable_end();
666 op_range operands() const { return op_range(op_begin(), op_end()); }
668 const MDOperand &getOperand(unsigned I) const {
669 assert(I < NumOperands && "Out of range");
670 return op_begin()[I];
673 /// \brief Return number of MDNode operands.
674 unsigned getNumOperands() const { return NumOperands; }
676 /// \brief Methods for support type inquiry through isa, cast, and dyn_cast:
677 static bool classof(const Metadata *MD) {
678 return MD->getMetadataID() == GenericMDNodeKind ||
679 MD->getMetadataID() == MDNodeFwdDeclKind;
682 /// \brief Check whether MDNode is a vtable access.
683 bool isTBAAVtableAccess() const;
685 /// \brief Methods for metadata merging.
686 static MDNode *concatenate(MDNode *A, MDNode *B);
687 static MDNode *intersect(MDNode *A, MDNode *B);
688 static MDNode *getMostGenericTBAA(MDNode *A, MDNode *B);
689 static AAMDNodes getMostGenericAA(const AAMDNodes &A, const AAMDNodes &B);
690 static MDNode *getMostGenericFPMath(MDNode *A, MDNode *B);
691 static MDNode *getMostGenericRange(MDNode *A, MDNode *B);
694 /// \brief Generic metadata node.
696 /// Generic metadata nodes, with opt-out support for uniquing.
698 /// Although nodes are uniqued by default, \a GenericMDNode has no support for
699 /// RAUW. If an operand change (due to RAUW or otherwise) causes a uniquing
700 /// collision, the uniquing bit is dropped.
702 /// TODO: Make uniquing opt-out (status: mandatory, sometimes dropped).
703 class GenericMDNode : public MDNode {
704 friend class Metadata;
706 friend class LLVMContextImpl;
707 friend class ReplaceableMetadataImpl;
709 /// \brief Support RAUW as long as one of its arguments is replaceable.
711 /// If an operand is an \a MDNodeFwdDecl (or a replaceable \a GenericMDNode),
712 /// support RAUW to support uniquing as forward declarations are resolved.
713 /// As soon as operands have been resolved, drop support.
715 /// FIXME: Save memory by storing this in a pointer union with the
716 /// LLVMContext, and adding an LLVMContext reference to RMI.
717 std::unique_ptr<ReplaceableMetadataImpl> ReplaceableUses;
719 GenericMDNode(LLVMContext &C, ArrayRef<Metadata *> Vals);
722 void setHash(unsigned Hash) { MDNodeSubclassData = Hash; }
725 /// \brief Get the hash, if any.
726 unsigned getHash() const { return MDNodeSubclassData; }
728 static bool classof(const Metadata *MD) {
729 return MD->getMetadataID() == GenericMDNodeKind;
732 /// \brief Check whether any operands are forward declarations.
734 /// Returns \c true as long as any operands (or their operands, etc.) are \a
737 /// As forward declarations are resolved, their containers should get
738 /// resolved automatically. However, if this (or one of its operands) is
739 /// involved in a cycle, \a resolveCycles() needs to be called explicitly.
740 bool isResolved() const { return !ReplaceableUses; }
742 /// \brief Resolve cycles.
744 /// Once all forward declarations have been resolved, force cycles to be
747 /// \pre No operands (or operands' operands, etc.) are \a MDNodeFwdDecl.
748 void resolveCycles();
751 void handleChangedOperand(void *Ref, Metadata *New);
753 bool hasUnresolvedOperands() const { return SubclassData32; }
754 void incrementUnresolvedOperands() { ++SubclassData32; }
755 void decrementUnresolvedOperands() { --SubclassData32; }
759 /// \brief Forward declaration of metadata.
761 /// Forward declaration of metadata, in the form of a metadata node. Unlike \a
762 /// GenericMDNode, this class has support for RAUW and is suitable for forward
764 class MDNodeFwdDecl : public MDNode, ReplaceableMetadataImpl {
765 friend class Metadata;
767 friend class ReplaceableMetadataImpl;
769 MDNodeFwdDecl(LLVMContext &C, ArrayRef<Metadata *> Vals)
770 : MDNode(C, MDNodeFwdDeclKind, Vals) {}
771 ~MDNodeFwdDecl() { dropAllReferences(); }
774 static bool classof(const Metadata *MD) {
775 return MD->getMetadataID() == MDNodeFwdDeclKind;
778 using ReplaceableMetadataImpl::replaceAllUsesWith;
781 //===----------------------------------------------------------------------===//
782 /// \brief A tuple of MDNodes.
784 /// Despite its name, a NamedMDNode isn't itself an MDNode. NamedMDNodes belong
785 /// to modules, have names, and contain lists of MDNodes.
787 /// TODO: Inherit from Metadata.
788 class NamedMDNode : public ilist_node<NamedMDNode> {
789 friend class SymbolTableListTraits<NamedMDNode, Module>;
790 friend struct ilist_traits<NamedMDNode>;
791 friend class LLVMContextImpl;
793 NamedMDNode(const NamedMDNode &) LLVM_DELETED_FUNCTION;
797 void *Operands; // SmallVector<TrackingMDRef, 4>
799 void setParent(Module *M) { Parent = M; }
801 explicit NamedMDNode(const Twine &N);
803 template<class T1, class T2>
804 class op_iterator_impl :
805 public std::iterator<std::bidirectional_iterator_tag, T2> {
806 const NamedMDNode *Node;
808 op_iterator_impl(const NamedMDNode *N, unsigned i) : Node(N), Idx(i) { }
810 friend class NamedMDNode;
813 op_iterator_impl() : Node(nullptr), Idx(0) { }
815 bool operator==(const op_iterator_impl &o) const { return Idx == o.Idx; }
816 bool operator!=(const op_iterator_impl &o) const { return Idx != o.Idx; }
817 op_iterator_impl &operator++() {
821 op_iterator_impl operator++(int) {
822 op_iterator_impl tmp(*this);
826 op_iterator_impl &operator--() {
830 op_iterator_impl operator--(int) {
831 op_iterator_impl tmp(*this);
836 T1 operator*() const { return Node->getOperand(Idx); }
840 /// \brief Drop all references and remove the node from parent module.
841 void eraseFromParent();
843 /// \brief Remove all uses and clear node vector.
844 void dropAllReferences();
848 /// \brief Get the module that holds this named metadata collection.
849 inline Module *getParent() { return Parent; }
850 inline const Module *getParent() const { return Parent; }
852 MDNode *getOperand(unsigned i) const;
853 unsigned getNumOperands() const;
854 void addOperand(MDNode *M);
855 StringRef getName() const;
856 void print(raw_ostream &ROS) const;
859 // ---------------------------------------------------------------------------
860 // Operand Iterator interface...
862 typedef op_iterator_impl<MDNode *, MDNode> op_iterator;
863 op_iterator op_begin() { return op_iterator(this, 0); }
864 op_iterator op_end() { return op_iterator(this, getNumOperands()); }
866 typedef op_iterator_impl<const MDNode *, MDNode> const_op_iterator;
867 const_op_iterator op_begin() const { return const_op_iterator(this, 0); }
868 const_op_iterator op_end() const { return const_op_iterator(this, getNumOperands()); }
870 inline iterator_range<op_iterator> operands() {
871 return iterator_range<op_iterator>(op_begin(), op_end());
873 inline iterator_range<const_op_iterator> operands() const {
874 return iterator_range<const_op_iterator>(op_begin(), op_end());
878 } // end llvm namespace