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 Active type of storage.
51 enum StorageType { Uniqued, Distinct, Temporary };
53 /// \brief Storage flag for non-uniqued, otherwise unowned, metadata.
54 StorageType Storage : 2;
55 // TODO: expose remaining bits to subclasses.
57 unsigned short SubclassData16;
58 unsigned SubclassData32;
65 ConstantAsMetadataKind,
71 Metadata(unsigned ID, StorageType Storage)
72 : SubclassID(ID), Storage(Storage), SubclassData16(0), SubclassData32(0) {
76 /// \brief Store this in a big non-uniqued untyped bucket.
77 bool isStoredDistinctInContext() const { return Storage == Distinct; }
79 /// \brief Default handling of a changed operand, which asserts.
81 /// If subclasses pass themselves in as owners to a tracking node reference,
82 /// they must provide an implementation of this method.
83 void handleChangedOperand(void *, Metadata *) {
84 llvm_unreachable("Unimplemented in Metadata subclass");
88 unsigned getMetadataID() const { return SubclassID; }
90 /// \brief User-friendly dump.
92 void print(raw_ostream &OS) const;
93 void printAsOperand(raw_ostream &OS, bool PrintType = true,
94 const Module *M = nullptr) const;
97 #define HANDLE_METADATA(CLASS) class CLASS;
98 #include "llvm/IR/Metadata.def"
100 inline raw_ostream &operator<<(raw_ostream &OS, const Metadata &MD) {
105 /// \brief Metadata wrapper in the Value hierarchy.
107 /// A member of the \a Value hierarchy to represent a reference to metadata.
108 /// This allows, e.g., instrinsics to have metadata as operands.
110 /// Notably, this is the only thing in either hierarchy that is allowed to
111 /// reference \a LocalAsMetadata.
112 class MetadataAsValue : public Value {
113 friend class ReplaceableMetadataImpl;
114 friend class LLVMContextImpl;
118 MetadataAsValue(Type *Ty, Metadata *MD);
121 /// \brief Drop use of metadata (during teardown).
122 void dropUse() { MD = nullptr; }
125 static MetadataAsValue *get(LLVMContext &Context, Metadata *MD);
126 static MetadataAsValue *getIfExists(LLVMContext &Context, Metadata *MD);
127 Metadata *getMetadata() const { return MD; }
129 static bool classof(const Value *V) {
130 return V->getValueID() == MetadataAsValueVal;
134 void handleChangedMetadata(Metadata *MD);
139 /// \brief Shared implementation of use-lists for replaceable metadata.
141 /// Most metadata cannot be RAUW'ed. This is a shared implementation of
142 /// use-lists and associated API for the two that support it (\a ValueAsMetadata
143 /// and \a TempMDNode).
144 class ReplaceableMetadataImpl {
145 friend class MetadataTracking;
148 typedef MetadataTracking::OwnerTy OwnerTy;
152 SmallDenseMap<void *, std::pair<OwnerTy, uint64_t>, 4> UseMap;
155 ReplaceableMetadataImpl() : NextIndex(0) {}
156 ~ReplaceableMetadataImpl() {
157 assert(UseMap.empty() && "Cannot destroy in-use replaceable metadata");
160 /// \brief Replace all uses of this with MD.
162 /// Replace all uses of this with \c MD, which is allowed to be null.
163 void replaceAllUsesWith(Metadata *MD);
165 /// \brief Resolve all uses of this.
167 /// Resolve all uses of this, turning off RAUW permanently. If \c
168 /// ResolveUsers, call \a UniquableMDNode::resolve() on any users whose last
169 /// operand is resolved.
170 void resolveAllUses(bool ResolveUsers = true);
173 void addRef(void *Ref, OwnerTy Owner);
174 void dropRef(void *Ref);
175 void moveRef(void *Ref, void *New, const Metadata &MD);
177 static ReplaceableMetadataImpl *get(Metadata &MD);
180 /// \brief Value wrapper in the Metadata hierarchy.
182 /// This is a custom value handle that allows other metadata to refer to
183 /// classes in the Value hierarchy.
185 /// Because of full uniquing support, each value is only wrapped by a single \a
186 /// ValueAsMetadata object, so the lookup maps are far more efficient than
187 /// those using ValueHandleBase.
188 class ValueAsMetadata : public Metadata, ReplaceableMetadataImpl {
189 friend class ReplaceableMetadataImpl;
190 friend class LLVMContextImpl;
194 /// \brief Drop users without RAUW (during teardown).
196 ReplaceableMetadataImpl::resolveAllUses(/* ResolveUsers */ false);
200 ValueAsMetadata(unsigned ID, Value *V)
201 : Metadata(ID, Uniqued), V(V) {
202 assert(V && "Expected valid value");
204 ~ValueAsMetadata() {}
207 static ValueAsMetadata *get(Value *V);
208 static ConstantAsMetadata *getConstant(Value *C) {
209 return cast<ConstantAsMetadata>(get(C));
211 static LocalAsMetadata *getLocal(Value *Local) {
212 return cast<LocalAsMetadata>(get(Local));
215 static ValueAsMetadata *getIfExists(Value *V);
216 static ConstantAsMetadata *getConstantIfExists(Value *C) {
217 return cast_or_null<ConstantAsMetadata>(getIfExists(C));
219 static LocalAsMetadata *getLocalIfExists(Value *Local) {
220 return cast_or_null<LocalAsMetadata>(getIfExists(Local));
223 Value *getValue() const { return V; }
224 Type *getType() const { return V->getType(); }
225 LLVMContext &getContext() const { return V->getContext(); }
227 static void handleDeletion(Value *V);
228 static void handleRAUW(Value *From, Value *To);
231 /// \brief Handle collisions after \a Value::replaceAllUsesWith().
233 /// RAUW isn't supported directly for \a ValueAsMetadata, but if the wrapped
234 /// \a Value gets RAUW'ed and the target already exists, this is used to
235 /// merge the two metadata nodes.
236 void replaceAllUsesWith(Metadata *MD) {
237 ReplaceableMetadataImpl::replaceAllUsesWith(MD);
241 static bool classof(const Metadata *MD) {
242 return MD->getMetadataID() == LocalAsMetadataKind ||
243 MD->getMetadataID() == ConstantAsMetadataKind;
247 class ConstantAsMetadata : public ValueAsMetadata {
248 friend class ValueAsMetadata;
250 ConstantAsMetadata(Constant *C)
251 : ValueAsMetadata(ConstantAsMetadataKind, C) {}
254 static ConstantAsMetadata *get(Constant *C) {
255 return ValueAsMetadata::getConstant(C);
257 static ConstantAsMetadata *getIfExists(Constant *C) {
258 return ValueAsMetadata::getConstantIfExists(C);
261 Constant *getValue() const {
262 return cast<Constant>(ValueAsMetadata::getValue());
265 static bool classof(const Metadata *MD) {
266 return MD->getMetadataID() == ConstantAsMetadataKind;
270 class LocalAsMetadata : public ValueAsMetadata {
271 friend class ValueAsMetadata;
273 LocalAsMetadata(Value *Local)
274 : ValueAsMetadata(LocalAsMetadataKind, Local) {
275 assert(!isa<Constant>(Local) && "Expected local value");
279 static LocalAsMetadata *get(Value *Local) {
280 return ValueAsMetadata::getLocal(Local);
282 static LocalAsMetadata *getIfExists(Value *Local) {
283 return ValueAsMetadata::getLocalIfExists(Local);
286 static bool classof(const Metadata *MD) {
287 return MD->getMetadataID() == LocalAsMetadataKind;
291 /// \brief Transitional API for extracting constants from Metadata.
293 /// This namespace contains transitional functions for metadata that points to
296 /// In prehistory -- when metadata was a subclass of \a Value -- \a MDNode
297 /// operands could refer to any \a Value. There's was a lot of code like this:
301 /// auto *CI = dyn_cast<ConstantInt>(N->getOperand(2));
304 /// Now that \a Value and \a Metadata are in separate hierarchies, maintaining
305 /// the semantics for \a isa(), \a cast(), \a dyn_cast() (etc.) requires three
306 /// steps: cast in the \a Metadata hierarchy, extraction of the \a Value, and
307 /// cast in the \a Value hierarchy. Besides creating boiler-plate, this
308 /// requires subtle control flow changes.
310 /// The end-goal is to create a new type of metadata, called (e.g.) \a MDInt,
311 /// so that metadata can refer to numbers without traversing a bridge to the \a
312 /// Value hierarchy. In this final state, the code above would look like this:
316 /// auto *MI = dyn_cast<MDInt>(N->getOperand(2));
319 /// The API in this namespace supports the transition. \a MDInt doesn't exist
320 /// yet, and even once it does, changing each metadata schema to use it is its
321 /// own mini-project. In the meantime this API prevents us from introducing
322 /// complex and bug-prone control flow that will disappear in the end. In
323 /// particular, the above code looks like this:
327 /// auto *CI = mdconst::dyn_extract<ConstantInt>(N->getOperand(2));
330 /// The full set of provided functions includes:
332 /// mdconst::hasa <=> isa
333 /// mdconst::extract <=> cast
334 /// mdconst::extract_or_null <=> cast_or_null
335 /// mdconst::dyn_extract <=> dyn_cast
336 /// mdconst::dyn_extract_or_null <=> dyn_cast_or_null
338 /// The target of the cast must be a subclass of \a Constant.
342 template <class T> T &make();
343 template <class T, class Result> struct HasDereference {
346 template <size_t N> struct SFINAE {};
348 template <class U, class V>
349 static Yes &hasDereference(SFINAE<sizeof(static_cast<V>(*make<U>()))> * = 0);
350 template <class U, class V> static No &hasDereference(...);
352 static const bool value =
353 sizeof(hasDereference<T, Result>(nullptr)) == sizeof(Yes);
355 template <class V, class M> struct IsValidPointer {
356 static const bool value = std::is_base_of<Constant, V>::value &&
357 HasDereference<M, const Metadata &>::value;
359 template <class V, class M> struct IsValidReference {
360 static const bool value = std::is_base_of<Constant, V>::value &&
361 std::is_convertible<M, const Metadata &>::value;
363 } // end namespace detail
365 /// \brief Check whether Metadata has a Value.
367 /// As an analogue to \a isa(), check whether \c MD has an \a Value inside of
369 template <class X, class Y>
370 inline typename std::enable_if<detail::IsValidPointer<X, Y>::value, bool>::type
372 assert(MD && "Null pointer sent into hasa");
373 if (auto *V = dyn_cast<ConstantAsMetadata>(MD))
374 return isa<X>(V->getValue());
377 template <class X, class Y>
379 typename std::enable_if<detail::IsValidReference<X, Y &>::value, bool>::type
384 /// \brief Extract a Value from Metadata.
386 /// As an analogue to \a cast(), extract the \a Value subclass \c X from \c MD.
387 template <class X, class Y>
388 inline typename std::enable_if<detail::IsValidPointer<X, Y>::value, X *>::type
390 return cast<X>(cast<ConstantAsMetadata>(MD)->getValue());
392 template <class X, class Y>
394 typename std::enable_if<detail::IsValidReference<X, Y &>::value, X *>::type
399 /// \brief Extract a Value from Metadata, allowing null.
401 /// As an analogue to \a cast_or_null(), extract the \a Value subclass \c X
402 /// from \c MD, allowing \c MD to be null.
403 template <class X, class Y>
404 inline typename std::enable_if<detail::IsValidPointer<X, Y>::value, X *>::type
405 extract_or_null(Y &&MD) {
406 if (auto *V = cast_or_null<ConstantAsMetadata>(MD))
407 return cast<X>(V->getValue());
411 /// \brief Extract a Value from Metadata, if any.
413 /// As an analogue to \a dyn_cast_or_null(), extract the \a Value subclass \c X
414 /// from \c MD, return null if \c MD doesn't contain a \a Value or if the \a
415 /// Value it does contain is of the wrong subclass.
416 template <class X, class Y>
417 inline typename std::enable_if<detail::IsValidPointer<X, Y>::value, X *>::type
418 dyn_extract(Y &&MD) {
419 if (auto *V = dyn_cast<ConstantAsMetadata>(MD))
420 return dyn_cast<X>(V->getValue());
424 /// \brief Extract a Value from Metadata, if any, allowing null.
426 /// As an analogue to \a dyn_cast_or_null(), extract the \a Value subclass \c X
427 /// from \c MD, return null if \c MD doesn't contain a \a Value or if the \a
428 /// Value it does contain is of the wrong subclass, allowing \c MD to be null.
429 template <class X, class Y>
430 inline typename std::enable_if<detail::IsValidPointer<X, Y>::value, X *>::type
431 dyn_extract_or_null(Y &&MD) {
432 if (auto *V = dyn_cast_or_null<ConstantAsMetadata>(MD))
433 return dyn_cast<X>(V->getValue());
437 } // end namespace mdconst
439 //===----------------------------------------------------------------------===//
440 /// \brief A single uniqued string.
442 /// These are used to efficiently contain a byte sequence for metadata.
443 /// MDString is always unnamed.
444 class MDString : public Metadata {
445 friend class StringMapEntry<MDString>;
447 MDString(const MDString &) LLVM_DELETED_FUNCTION;
448 MDString &operator=(MDString &&) LLVM_DELETED_FUNCTION;
449 MDString &operator=(const MDString &) LLVM_DELETED_FUNCTION;
451 StringMapEntry<MDString> *Entry;
452 MDString() : Metadata(MDStringKind, Uniqued), Entry(nullptr) {}
453 MDString(MDString &&) : Metadata(MDStringKind, Uniqued) {}
456 static MDString *get(LLVMContext &Context, StringRef Str);
457 static MDString *get(LLVMContext &Context, const char *Str) {
458 return get(Context, Str ? StringRef(Str) : StringRef());
461 StringRef getString() const;
463 unsigned getLength() const { return (unsigned)getString().size(); }
465 typedef StringRef::iterator iterator;
467 /// \brief Pointer to the first byte of the string.
468 iterator begin() const { return getString().begin(); }
470 /// \brief Pointer to one byte past the end of the string.
471 iterator end() const { return getString().end(); }
473 const unsigned char *bytes_begin() const { return getString().bytes_begin(); }
474 const unsigned char *bytes_end() const { return getString().bytes_end(); }
476 /// \brief Methods for support type inquiry through isa, cast, and dyn_cast.
477 static bool classof(const Metadata *MD) {
478 return MD->getMetadataID() == MDStringKind;
482 /// \brief A collection of metadata nodes that might be associated with a
483 /// memory access used by the alias-analysis infrastructure.
485 explicit AAMDNodes(MDNode *T = nullptr, MDNode *S = nullptr,
487 : TBAA(T), Scope(S), NoAlias(N) {}
489 bool operator==(const AAMDNodes &A) const {
490 return TBAA == A.TBAA && Scope == A.Scope && NoAlias == A.NoAlias;
493 bool operator!=(const AAMDNodes &A) const { return !(*this == A); }
495 LLVM_EXPLICIT operator bool() const { return TBAA || Scope || NoAlias; }
497 /// \brief The tag for type-based alias analysis.
500 /// \brief The tag for alias scope specification (used with noalias).
503 /// \brief The tag specifying the noalias scope.
507 // Specialize DenseMapInfo for AAMDNodes.
509 struct DenseMapInfo<AAMDNodes> {
510 static inline AAMDNodes getEmptyKey() {
511 return AAMDNodes(DenseMapInfo<MDNode *>::getEmptyKey(), 0, 0);
513 static inline AAMDNodes getTombstoneKey() {
514 return AAMDNodes(DenseMapInfo<MDNode *>::getTombstoneKey(), 0, 0);
516 static unsigned getHashValue(const AAMDNodes &Val) {
517 return DenseMapInfo<MDNode *>::getHashValue(Val.TBAA) ^
518 DenseMapInfo<MDNode *>::getHashValue(Val.Scope) ^
519 DenseMapInfo<MDNode *>::getHashValue(Val.NoAlias);
521 static bool isEqual(const AAMDNodes &LHS, const AAMDNodes &RHS) {
526 /// \brief Tracking metadata reference owned by Metadata.
528 /// Similar to \a TrackingMDRef, but it's expected to be owned by an instance
529 /// of \a Metadata, which has the option of registering itself for callbacks to
530 /// re-unique itself.
532 /// In particular, this is used by \a MDNode.
534 MDOperand(MDOperand &&) LLVM_DELETED_FUNCTION;
535 MDOperand(const MDOperand &) LLVM_DELETED_FUNCTION;
536 MDOperand &operator=(MDOperand &&) LLVM_DELETED_FUNCTION;
537 MDOperand &operator=(const MDOperand &) LLVM_DELETED_FUNCTION;
542 MDOperand() : MD(nullptr) {}
543 ~MDOperand() { untrack(); }
545 Metadata *get() const { return MD; }
546 operator Metadata *() const { return get(); }
547 Metadata *operator->() const { return get(); }
548 Metadata &operator*() const { return *get(); }
554 void reset(Metadata *MD, Metadata *Owner) {
561 void track(Metadata *Owner) {
564 MetadataTracking::track(this, *MD, *Owner);
566 MetadataTracking::track(MD);
570 assert(static_cast<void *>(this) == &MD && "Expected same address");
572 MetadataTracking::untrack(MD);
576 template <> struct simplify_type<MDOperand> {
577 typedef Metadata *SimpleType;
578 static SimpleType getSimplifiedValue(MDOperand &MD) { return MD.get(); }
581 template <> struct simplify_type<const MDOperand> {
582 typedef Metadata *SimpleType;
583 static SimpleType getSimplifiedValue(const MDOperand &MD) { return MD.get(); }
586 //===----------------------------------------------------------------------===//
587 /// \brief Tuple of metadata.
588 class MDNode : public Metadata {
589 MDNode(const MDNode &) LLVM_DELETED_FUNCTION;
590 void operator=(const MDNode &) LLVM_DELETED_FUNCTION;
591 void *operator new(size_t) LLVM_DELETED_FUNCTION;
593 LLVMContext &Context;
594 unsigned NumOperands;
597 unsigned MDNodeSubclassData;
599 void *operator new(size_t Size, unsigned NumOps);
600 void operator delete(void *Mem);
602 /// \brief Required by std, but never called.
603 void operator delete(void *, unsigned) {
604 llvm_unreachable("Constructor throws?");
607 /// \brief Required by std, but never called.
608 void operator delete(void *, unsigned, bool) {
609 llvm_unreachable("Constructor throws?");
612 MDNode(LLVMContext &Context, unsigned ID, StorageType Storage,
613 ArrayRef<Metadata *> MDs);
616 void dropAllReferences();
618 MDOperand *mutable_begin() { return mutable_end() - NumOperands; }
619 MDOperand *mutable_end() { return reinterpret_cast<MDOperand *>(this); }
622 static inline MDNode *get(LLVMContext &Context, ArrayRef<Metadata *> MDs);
623 static inline MDNode *getIfExists(LLVMContext &Context,
624 ArrayRef<Metadata *> MDs);
625 static inline MDNode *getDistinct(LLVMContext &Context,
626 ArrayRef<Metadata *> MDs);
628 /// \brief Return a temporary MDNode
630 /// For use in constructing cyclic MDNode structures. A temporary MDNode is
631 /// not uniqued, may be RAUW'd, and must be manually deleted with
633 static MDNodeFwdDecl *getTemporary(LLVMContext &Context,
634 ArrayRef<Metadata *> MDs);
636 /// \brief Deallocate a node created by getTemporary.
638 /// The node must not have any users.
639 static void deleteTemporary(MDNode *N);
641 LLVMContext &getContext() const { return Context; }
643 /// \brief Replace a specific operand.
644 void replaceOperandWith(unsigned I, Metadata *New);
646 /// \brief Check if node is fully resolved.
647 bool isResolved() const;
649 bool isUniqued() const { return Storage == Uniqued; }
650 bool isDistinct() const { return Storage == Distinct; }
651 bool isTemporary() const { return Storage == Temporary; }
654 /// \brief Set an operand.
656 /// Sets the operand directly, without worrying about uniquing.
657 void setOperand(unsigned I, Metadata *New);
660 typedef const MDOperand *op_iterator;
661 typedef iterator_range<op_iterator> op_range;
663 op_iterator op_begin() const {
664 return const_cast<MDNode *>(this)->mutable_begin();
666 op_iterator op_end() const {
667 return const_cast<MDNode *>(this)->mutable_end();
669 op_range operands() const { return op_range(op_begin(), op_end()); }
671 const MDOperand &getOperand(unsigned I) const {
672 assert(I < NumOperands && "Out of range");
673 return op_begin()[I];
676 /// \brief Return number of MDNode operands.
677 unsigned getNumOperands() const { return NumOperands; }
679 /// \brief Methods for support type inquiry through isa, cast, and dyn_cast:
680 static bool classof(const Metadata *MD) {
681 return MD->getMetadataID() == MDTupleKind ||
682 MD->getMetadataID() == MDLocationKind ||
683 MD->getMetadataID() == MDNodeFwdDeclKind;
686 /// \brief Check whether MDNode is a vtable access.
687 bool isTBAAVtableAccess() const;
689 /// \brief Methods for metadata merging.
690 static MDNode *concatenate(MDNode *A, MDNode *B);
691 static MDNode *intersect(MDNode *A, MDNode *B);
692 static MDNode *getMostGenericTBAA(MDNode *A, MDNode *B);
693 static AAMDNodes getMostGenericAA(const AAMDNodes &A, const AAMDNodes &B);
694 static MDNode *getMostGenericFPMath(MDNode *A, MDNode *B);
695 static MDNode *getMostGenericRange(MDNode *A, MDNode *B);
698 /// \brief Uniquable metadata node.
700 /// A uniquable metadata node. This contains the basic functionality
701 /// for implementing sub-types of \a MDNode that can be uniqued like
704 /// There is limited support for RAUW at construction time. At
705 /// construction time, if any operands are an instance of \a
706 /// MDNodeFwdDecl (or another unresolved \a UniquableMDNode, which
707 /// indicates an \a MDNodeFwdDecl in its path), the node itself will be
708 /// unresolved. As soon as all operands become resolved, it will drop
709 /// RAUW support permanently.
711 /// If an unresolved node is part of a cycle, \a resolveCycles() needs
712 /// to be called on some member of the cycle when each \a MDNodeFwdDecl
713 /// has been removed.
714 class UniquableMDNode : public MDNode {
715 friend class ReplaceableMetadataImpl;
717 friend class LLVMContextImpl;
719 /// \brief Support RAUW as long as one of its arguments is replaceable.
721 /// FIXME: Save memory by storing this in a pointer union with the
722 /// LLVMContext, and adding an LLVMContext reference to RMI.
723 std::unique_ptr<ReplaceableMetadataImpl> ReplaceableUses;
726 /// \brief Create a new node.
728 /// If \c AllowRAUW, then if any operands are unresolved support RAUW. RAUW
729 /// will be dropped once all operands have been resolved (or if \a
730 /// resolveCycles() is called).
731 UniquableMDNode(LLVMContext &C, unsigned ID, StorageType Storage,
732 ArrayRef<Metadata *> Vals);
733 ~UniquableMDNode() {}
735 void storeDistinctInContext();
738 static bool classof(const Metadata *MD) {
739 return MD->getMetadataID() == MDTupleKind ||
740 MD->getMetadataID() == MDLocationKind;
743 /// \brief Check whether any operands are forward declarations.
745 /// Returns \c true as long as any operands (or their operands, etc.) are \a
748 /// As forward declarations are resolved, their containers should get
749 /// resolved automatically. However, if this (or one of its operands) is
750 /// involved in a cycle, \a resolveCycles() needs to be called explicitly.
751 bool isResolved() const { return !ReplaceableUses; }
753 /// \brief Resolve cycles.
755 /// Once all forward declarations have been resolved, force cycles to be
758 /// \pre No operands (or operands' operands, etc.) are \a MDNodeFwdDecl.
759 void resolveCycles();
762 void handleChangedOperand(void *Ref, Metadata *New);
765 void resolveAfterOperandChange(Metadata *Old, Metadata *New);
766 void decrementUnresolvedOperandCount();
768 void deleteAsSubclass();
769 UniquableMDNode *uniquify();
770 void eraseFromStore();
773 /// \brief Tuple of metadata.
775 /// This is the simple \a MDNode arbitrary tuple. Nodes are uniqued by
776 /// default based on their operands.
777 class MDTuple : public UniquableMDNode {
778 friend class LLVMContextImpl;
779 friend class UniquableMDNode;
781 MDTuple(LLVMContext &C, StorageType Storage, ArrayRef<Metadata *> Vals)
782 : UniquableMDNode(C, MDTupleKind, Storage, Vals) {}
783 ~MDTuple() { dropAllReferences(); }
785 void setHash(unsigned Hash) { MDNodeSubclassData = Hash; }
786 void recalculateHash();
788 static MDTuple *getImpl(LLVMContext &Context, ArrayRef<Metadata *> MDs,
792 /// \brief Get the hash, if any.
793 unsigned getHash() const { return MDNodeSubclassData; }
795 static MDTuple *get(LLVMContext &Context, ArrayRef<Metadata *> MDs) {
796 return getImpl(Context, MDs, /* ShouldCreate */ true);
798 static MDTuple *getIfExists(LLVMContext &Context, ArrayRef<Metadata *> MDs) {
799 return getImpl(Context, MDs, /* ShouldCreate */ false);
802 /// \brief Return a distinct node.
804 /// Return a distinct node -- i.e., a node that is not uniqued.
805 static MDTuple *getDistinct(LLVMContext &Context, ArrayRef<Metadata *> MDs);
807 static bool classof(const Metadata *MD) {
808 return MD->getMetadataID() == MDTupleKind;
812 MDTuple *uniquifyImpl();
813 void eraseFromStoreImpl();
816 MDNode *MDNode::get(LLVMContext &Context, ArrayRef<Metadata *> MDs) {
817 return MDTuple::get(Context, MDs);
819 MDNode *MDNode::getIfExists(LLVMContext &Context, ArrayRef<Metadata *> MDs) {
820 return MDTuple::getIfExists(Context, MDs);
822 MDNode *MDNode::getDistinct(LLVMContext &Context, ArrayRef<Metadata *> MDs) {
823 return MDTuple::getDistinct(Context, MDs);
826 /// \brief Debug location.
828 /// A debug location in source code, used for debug info and otherwise.
829 class MDLocation : public UniquableMDNode {
830 friend class LLVMContextImpl;
831 friend class UniquableMDNode;
833 MDLocation(LLVMContext &C, StorageType Storage, unsigned Line,
834 unsigned Column, ArrayRef<Metadata *> MDs);
835 ~MDLocation() { dropAllReferences(); }
837 static MDLocation *constructHelper(LLVMContext &Context, StorageType Storage,
838 unsigned Line, unsigned Column,
839 Metadata *Scope, Metadata *InlinedAt);
841 static MDLocation *getImpl(LLVMContext &Context, unsigned Line,
842 unsigned Column, Metadata *Scope,
843 Metadata *InlinedAt, bool ShouldCreate);
845 // Disallow replacing operands.
846 void replaceOperandWith(unsigned I, Metadata *New) LLVM_DELETED_FUNCTION;
849 static MDLocation *get(LLVMContext &Context, unsigned Line, unsigned Column,
850 Metadata *Scope, Metadata *InlinedAt = nullptr) {
851 return getImpl(Context, Line, Column, Scope, InlinedAt,
852 /* ShouldCreate */ true);
854 static MDLocation *getIfExists(LLVMContext &Context, unsigned Line,
855 unsigned Column, Metadata *Scope,
856 Metadata *InlinedAt = nullptr) {
857 return getImpl(Context, Line, Column, Scope, InlinedAt,
858 /* ShouldCreate */ false);
860 static MDLocation *getDistinct(LLVMContext &Context, unsigned Line,
861 unsigned Column, Metadata *Scope,
862 Metadata *InlinedAt = nullptr);
864 unsigned getLine() const { return MDNodeSubclassData; }
865 unsigned getColumn() const { return SubclassData16; }
866 Metadata *getScope() const { return getOperand(0); }
867 Metadata *getInlinedAt() const {
868 if (getNumOperands() == 2)
869 return getOperand(1);
873 static bool classof(const Metadata *MD) {
874 return MD->getMetadataID() == MDLocationKind;
878 MDLocation *uniquifyImpl();
879 void eraseFromStoreImpl();
882 /// \brief Forward declaration of metadata.
884 /// Forward declaration of metadata, in the form of a basic tuple. Unlike \a
885 /// MDTuple, this class has full support for RAUW, is not owned, is not
886 /// uniqued, and is suitable for forward references.
887 class MDNodeFwdDecl : public MDNode, ReplaceableMetadataImpl {
888 friend class Metadata;
889 friend class ReplaceableMetadataImpl;
891 MDNodeFwdDecl(LLVMContext &C, ArrayRef<Metadata *> Vals)
892 : MDNode(C, MDNodeFwdDeclKind, Temporary, Vals) {}
895 ~MDNodeFwdDecl() { dropAllReferences(); }
897 // MSVC doesn't see the alternative: "using MDNode::operator delete".
898 void operator delete(void *Mem) { MDNode::operator delete(Mem); }
900 static MDNodeFwdDecl *get(LLVMContext &Context, ArrayRef<Metadata *> MDs) {
901 return new (MDs.size()) MDNodeFwdDecl(Context, MDs);
904 static bool classof(const Metadata *MD) {
905 return MD->getMetadataID() == MDNodeFwdDeclKind;
908 using ReplaceableMetadataImpl::replaceAllUsesWith;
911 //===----------------------------------------------------------------------===//
912 /// \brief A tuple of MDNodes.
914 /// Despite its name, a NamedMDNode isn't itself an MDNode. NamedMDNodes belong
915 /// to modules, have names, and contain lists of MDNodes.
917 /// TODO: Inherit from Metadata.
918 class NamedMDNode : public ilist_node<NamedMDNode> {
919 friend class SymbolTableListTraits<NamedMDNode, Module>;
920 friend struct ilist_traits<NamedMDNode>;
921 friend class LLVMContextImpl;
923 NamedMDNode(const NamedMDNode &) LLVM_DELETED_FUNCTION;
927 void *Operands; // SmallVector<TrackingMDRef, 4>
929 void setParent(Module *M) { Parent = M; }
931 explicit NamedMDNode(const Twine &N);
933 template<class T1, class T2>
934 class op_iterator_impl :
935 public std::iterator<std::bidirectional_iterator_tag, T2> {
936 const NamedMDNode *Node;
938 op_iterator_impl(const NamedMDNode *N, unsigned i) : Node(N), Idx(i) { }
940 friend class NamedMDNode;
943 op_iterator_impl() : Node(nullptr), Idx(0) { }
945 bool operator==(const op_iterator_impl &o) const { return Idx == o.Idx; }
946 bool operator!=(const op_iterator_impl &o) const { return Idx != o.Idx; }
947 op_iterator_impl &operator++() {
951 op_iterator_impl operator++(int) {
952 op_iterator_impl tmp(*this);
956 op_iterator_impl &operator--() {
960 op_iterator_impl operator--(int) {
961 op_iterator_impl tmp(*this);
966 T1 operator*() const { return Node->getOperand(Idx); }
970 /// \brief Drop all references and remove the node from parent module.
971 void eraseFromParent();
973 /// \brief Remove all uses and clear node vector.
974 void dropAllReferences();
978 /// \brief Get the module that holds this named metadata collection.
979 inline Module *getParent() { return Parent; }
980 inline const Module *getParent() const { return Parent; }
982 MDNode *getOperand(unsigned i) const;
983 unsigned getNumOperands() const;
984 void addOperand(MDNode *M);
985 void setOperand(unsigned I, MDNode *New);
986 StringRef getName() const;
987 void print(raw_ostream &ROS) const;
990 // ---------------------------------------------------------------------------
991 // Operand Iterator interface...
993 typedef op_iterator_impl<MDNode *, MDNode> op_iterator;
994 op_iterator op_begin() { return op_iterator(this, 0); }
995 op_iterator op_end() { return op_iterator(this, getNumOperands()); }
997 typedef op_iterator_impl<const MDNode *, MDNode> const_op_iterator;
998 const_op_iterator op_begin() const { return const_op_iterator(this, 0); }
999 const_op_iterator op_end() const { return const_op_iterator(this, getNumOperands()); }
1001 inline iterator_range<op_iterator> operands() {
1002 return iterator_range<op_iterator>(op_begin(), op_end());
1004 inline iterator_range<const_op_iterator> operands() const {
1005 return iterator_range<const_op_iterator>(op_begin(), op_end());
1009 } // end llvm namespace