1//===- llvm/IR/Metadata.h - Metadata definitions ----------------*- C++ -*-===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9/// @file
10/// This file contains the declarations for metadata subclasses.
11/// They represent the different flavors of metadata that live in LLVM.
12//
13//===----------------------------------------------------------------------===//
14
15#ifndef LLVM_IR_METADATA_H
16#define LLVM_IR_METADATA_H
17
18#include "llvm/ADT/ArrayRef.h"
19#include "llvm/ADT/DenseMap.h"
20#include "llvm/ADT/DenseMapInfo.h"
21#include "llvm/ADT/None.h"
22#include "llvm/ADT/PointerUnion.h"
23#include "llvm/ADT/STLExtras.h"
24#include "llvm/ADT/SmallVector.h"
25#include "llvm/ADT/StringMap.h"
26#include "llvm/ADT/StringRef.h"
27#include "llvm/ADT/ilist_node.h"
28#include "llvm/ADT/iterator_range.h"
29#include "llvm/IR/Constant.h"
30#include "llvm/IR/LLVMContext.h"
31#include "llvm/IR/Value.h"
32#include "llvm/Support/CBindingWrapping.h"
33#include "llvm/Support/Casting.h"
34#include "llvm/Support/ErrorHandling.h"
35#include <cassert>
36#include <cstddef>
37#include <cstdint>
38#include <iterator>
39#include <memory>
40#include <string>
41#include <type_traits>
42#include <utility>
43
44namespace llvm {
45
46class Module;
47class ModuleSlotTracker;
48class raw_ostream;
49class Type;
50
51enum LLVMConstants : uint32_t {
52 DEBUG_METADATA_VERSION = 3 // Current debug info version number.
53};
54
55/// Magic number in the value profile metadata showing a target has been
56/// promoted for the instruction and shouldn't be promoted again.
57const uint64_t NOMORE_ICP_MAGICNUM = -1;
58
59/// Root of the metadata hierarchy.
60///
61/// This is a root class for typeless data in the IR.
62class Metadata {
63 friend class ReplaceableMetadataImpl;
64
65 /// RTTI.
66 const unsigned char SubclassID;
67
68protected:
69 /// Active type of storage.
70 enum StorageType { Uniqued, Distinct, Temporary };
71
72 /// Storage flag for non-uniqued, otherwise unowned, metadata.
73 unsigned char Storage : 7;
74
75 unsigned char SubclassData1 : 1;
76 unsigned short SubclassData16 = 0;
77 unsigned SubclassData32 = 0;
78
79public:
80 enum MetadataKind {
81#define HANDLE_METADATA_LEAF(CLASS) CLASS##Kind,
82#include "llvm/IR/Metadata.def"
83 };
84
85protected:
86 Metadata(unsigned ID, StorageType Storage)
87 : SubclassID(ID), Storage(Storage), SubclassData1(false) {
88 static_assert(sizeof(*this) == 8, "Metadata fields poorly packed");
89 }
90
91 ~Metadata() = default;
92
93 /// Default handling of a changed operand, which asserts.
94 ///
95 /// If subclasses pass themselves in as owners to a tracking node reference,
96 /// they must provide an implementation of this method.
97 void handleChangedOperand(void *, Metadata *) {
98 llvm_unreachable("Unimplemented in Metadata subclass");
99 }
100
101public:
102 unsigned getMetadataID() const { return SubclassID; }
103
104 /// User-friendly dump.
105 ///
106 /// If \c M is provided, metadata nodes will be numbered canonically;
107 /// otherwise, pointer addresses are substituted.
108 ///
109 /// Note: this uses an explicit overload instead of default arguments so that
110 /// the nullptr version is easy to call from a debugger.
111 ///
112 /// @{
113 void dump() const;
114 void dump(const Module *M) const;
115 /// @}
116
117 /// Print.
118 ///
119 /// Prints definition of \c this.
120 ///
121 /// If \c M is provided, metadata nodes will be numbered canonically;
122 /// otherwise, pointer addresses are substituted.
123 /// @{
124 void print(raw_ostream &OS, const Module *M = nullptr,
125 bool IsForDebug = false) const;
126 void print(raw_ostream &OS, ModuleSlotTracker &MST, const Module *M = nullptr,
127 bool IsForDebug = false) const;
128 /// @}
129
130 /// Print as operand.
131 ///
132 /// Prints reference of \c this.
133 ///
134 /// If \c M is provided, metadata nodes will be numbered canonically;
135 /// otherwise, pointer addresses are substituted.
136 /// @{
137 void printAsOperand(raw_ostream &OS, const Module *M = nullptr) const;
138 void printAsOperand(raw_ostream &OS, ModuleSlotTracker &MST,
139 const Module *M = nullptr) const;
140 /// @}
141};
142
143// Create wrappers for C Binding types (see CBindingWrapping.h).
144DEFINE_ISA_CONVERSION_FUNCTIONS(Metadata, LLVMMetadataRef)
145
146// Specialized opaque metadata conversions.
147inline Metadata **unwrap(LLVMMetadataRef *MDs) {
148 return reinterpret_cast<Metadata**>(MDs);
149}
150
151#define HANDLE_METADATA(CLASS) class CLASS;
152#include "llvm/IR/Metadata.def"
153
154// Provide specializations of isa so that we don't need definitions of
155// subclasses to see if the metadata is a subclass.
156#define HANDLE_METADATA_LEAF(CLASS) \
157 template <> struct isa_impl<CLASS, Metadata> { \
158 static inline bool doit(const Metadata &MD) { \
159 return MD.getMetadataID() == Metadata::CLASS##Kind; \
160 } \
161 };
162#include "llvm/IR/Metadata.def"
163
164inline raw_ostream &operator<<(raw_ostream &OS, const Metadata &MD) {
165 MD.print(OS);
166 return OS;
167}
168
169/// Metadata wrapper in the Value hierarchy.
170///
171/// A member of the \a Value hierarchy to represent a reference to metadata.
172/// This allows, e.g., instrinsics to have metadata as operands.
173///
174/// Notably, this is the only thing in either hierarchy that is allowed to
175/// reference \a LocalAsMetadata.
176class MetadataAsValue : public Value {
177 friend class ReplaceableMetadataImpl;
178 friend class LLVMContextImpl;
179
180 Metadata *MD;
181
182 MetadataAsValue(Type *Ty, Metadata *MD);
183
184 /// Drop use of metadata (during teardown).
185 void dropUse() { MD = nullptr; }
186
187public:
188 ~MetadataAsValue();
189
190 static MetadataAsValue *get(LLVMContext &Context, Metadata *MD);
191 static MetadataAsValue *getIfExists(LLVMContext &Context, Metadata *MD);
192
193 Metadata *getMetadata() const { return MD; }
194
195 static bool classof(const Value *V) {
196 return V->getValueID() == MetadataAsValueVal;
197 }
198
199private:
200 void handleChangedMetadata(Metadata *MD);
201 void track();
202 void untrack();
203};
204
205/// API for tracking metadata references through RAUW and deletion.
206///
207/// Shared API for updating \a Metadata pointers in subclasses that support
208/// RAUW.
209///
210/// This API is not meant to be used directly. See \a TrackingMDRef for a
211/// user-friendly tracking reference.
212class MetadataTracking {
213public:
214 /// Track the reference to metadata.
215 ///
216 /// Register \c MD with \c *MD, if the subclass supports tracking. If \c *MD
217 /// gets RAUW'ed, \c MD will be updated to the new address. If \c *MD gets
218 /// deleted, \c MD will be set to \c nullptr.
219 ///
220 /// If tracking isn't supported, \c *MD will not change.
221 ///
222 /// \return true iff tracking is supported by \c MD.
223 static bool track(Metadata *&MD) {
224 return track(&MD, *MD, static_cast<Metadata *>(nullptr));
225 }
226
227 /// Track the reference to metadata for \a Metadata.
228 ///
229 /// As \a track(Metadata*&), but with support for calling back to \c Owner to
230 /// tell it that its operand changed. This could trigger \c Owner being
231 /// re-uniqued.
232 static bool track(void *Ref, Metadata &MD, Metadata &Owner) {
233 return track(Ref, MD, &Owner);
234 }
235
236 /// Track the reference to metadata for \a MetadataAsValue.
237 ///
238 /// As \a track(Metadata*&), but with support for calling back to \c Owner to
239 /// tell it that its operand changed. This could trigger \c Owner being
240 /// re-uniqued.
241 static bool track(void *Ref, Metadata &MD, MetadataAsValue &Owner) {
242 return track(Ref, MD, &Owner);
243 }
244
245 /// Stop tracking a reference to metadata.
246 ///
247 /// Stops \c *MD from tracking \c MD.
248 static void untrack(Metadata *&MD) { untrack(&MD, *MD); }
249 static void untrack(void *Ref, Metadata &MD);
250
251 /// Move tracking from one reference to another.
252 ///
253 /// Semantically equivalent to \c untrack(MD) followed by \c track(New),
254 /// except that ownership callbacks are maintained.
255 ///
256 /// Note: it is an error if \c *MD does not equal \c New.
257 ///
258 /// \return true iff tracking is supported by \c MD.
259 static bool retrack(Metadata *&MD, Metadata *&New) {
260 return retrack(&MD, *MD, &New);
261 }
262 static bool retrack(void *Ref, Metadata &MD, void *New);
263
264 /// Check whether metadata is replaceable.
265 static bool isReplaceable(const Metadata &MD);
266
267 using OwnerTy = PointerUnion<MetadataAsValue *, Metadata *>;
268
269private:
270 /// Track a reference to metadata for an owner.
271 ///
272 /// Generalized version of tracking.
273 static bool track(void *Ref, Metadata &MD, OwnerTy Owner);
274};
275
276/// Shared implementation of use-lists for replaceable metadata.
277///
278/// Most metadata cannot be RAUW'ed. This is a shared implementation of
279/// use-lists and associated API for the two that support it (\a ValueAsMetadata
280/// and \a TempMDNode).
281class ReplaceableMetadataImpl {
282 friend class MetadataTracking;
283
284public:
285 using OwnerTy = MetadataTracking::OwnerTy;
286
287private:
288 LLVMContext &Context;
289 uint64_t NextIndex = 0;
290 SmallDenseMap<void *, std::pair<OwnerTy, uint64_t>, 4> UseMap;
291
292public:
293 ReplaceableMetadataImpl(LLVMContext &Context) : Context(Context) {}
294
295 ~ReplaceableMetadataImpl() {
296 assert(UseMap.empty() && "Cannot destroy in-use replaceable metadata");
297 }
298
299 LLVMContext &getContext() const { return Context; }
300
301 /// Replace all uses of this with MD.
302 ///
303 /// Replace all uses of this with \c MD, which is allowed to be null.
304 void replaceAllUsesWith(Metadata *MD);
305
306 /// Returns the list of all DIArgList users of this.
307 SmallVector<Metadata *, 4> getAllArgListUsers();
308
309 /// Resolve all uses of this.
310 ///
311 /// Resolve all uses of this, turning off RAUW permanently. If \c
312 /// ResolveUsers, call \a MDNode::resolve() on any users whose last operand
313 /// is resolved.
314 void resolveAllUses(bool ResolveUsers = true);
315
316private:
317 void addRef(void *Ref, OwnerTy Owner);
318 void dropRef(void *Ref);
319 void moveRef(void *Ref, void *New, const Metadata &MD);
320
321 /// Lazily construct RAUW support on MD.
322 ///
323 /// If this is an unresolved MDNode, RAUW support will be created on-demand.
324 /// ValueAsMetadata always has RAUW support.
325 static ReplaceableMetadataImpl *getOrCreate(Metadata &MD);
326
327 /// Get RAUW support on MD, if it exists.
328 static ReplaceableMetadataImpl *getIfExists(Metadata &MD);
329
330 /// Check whether this node will support RAUW.
331 ///
332 /// Returns \c true unless getOrCreate() would return null.
333 static bool isReplaceable(const Metadata &MD);
334};
335
336/// Value wrapper in the Metadata hierarchy.
337///
338/// This is a custom value handle that allows other metadata to refer to
339/// classes in the Value hierarchy.
340///
341/// Because of full uniquing support, each value is only wrapped by a single \a
342/// ValueAsMetadata object, so the lookup maps are far more efficient than
343/// those using ValueHandleBase.
344class ValueAsMetadata : public Metadata, ReplaceableMetadataImpl {
345 friend class ReplaceableMetadataImpl;
346 friend class LLVMContextImpl;
347
348 Value *V;
349
350 /// Drop users without RAUW (during teardown).
351 void dropUsers() {
352 ReplaceableMetadataImpl::resolveAllUses(/* ResolveUsers */ false);
353 }
354
355protected:
356 ValueAsMetadata(unsigned ID, Value *V)
357 : Metadata(ID, Uniqued), ReplaceableMetadataImpl(V->getContext()), V(V) {
358 assert(V && "Expected valid value");
359 }
360
361 ~ValueAsMetadata() = default;
362
363public:
364 static ValueAsMetadata *get(Value *V);
365
366 static ConstantAsMetadata *getConstant(Value *C) {
367 return cast<ConstantAsMetadata>(get(C));
368 }
369
370 static LocalAsMetadata *getLocal(Value *Local) {
371 return cast<LocalAsMetadata>(get(Local));
372 }
373
374 static ValueAsMetadata *getIfExists(Value *V);
375
376 static ConstantAsMetadata *getConstantIfExists(Value *C) {
377 return cast_or_null<ConstantAsMetadata>(getIfExists(C));
378 }
379
380 static LocalAsMetadata *getLocalIfExists(Value *Local) {
381 return cast_or_null<LocalAsMetadata>(getIfExists(Local));
382 }
383
384 Value *getValue() const { return V; }
385 Type *getType() const { return V->getType(); }
386 LLVMContext &getContext() const { return V->getContext(); }
387
388 SmallVector<Metadata *, 4> getAllArgListUsers() {
389 return ReplaceableMetadataImpl::getAllArgListUsers();
390 }
391
392 static void handleDeletion(Value *V);
393 static void handleRAUW(Value *From, Value *To);
394
395protected:
396 /// Handle collisions after \a Value::replaceAllUsesWith().
397 ///
398 /// RAUW isn't supported directly for \a ValueAsMetadata, but if the wrapped
399 /// \a Value gets RAUW'ed and the target already exists, this is used to
400 /// merge the two metadata nodes.
401 void replaceAllUsesWith(Metadata *MD) {
402 ReplaceableMetadataImpl::replaceAllUsesWith(MD);
403 }
404
405public:
406 static bool classof(const Metadata *MD) {
407 return MD->getMetadataID() == LocalAsMetadataKind ||
408 MD->getMetadataID() == ConstantAsMetadataKind;
409 }
410};
411
412class ConstantAsMetadata : public ValueAsMetadata {
413 friend class ValueAsMetadata;
414
415 ConstantAsMetadata(Constant *C)
416 : ValueAsMetadata(ConstantAsMetadataKind, C) {}
417
418public:
419 static ConstantAsMetadata *get(Constant *C) {
420 return ValueAsMetadata::getConstant(C);
421 }
422
423 static ConstantAsMetadata *getIfExists(Constant *C) {
424 return ValueAsMetadata::getConstantIfExists(C);
425 }
426
427 Constant *getValue() const {
428 return cast<Constant>(ValueAsMetadata::getValue());
429 }
430
431 static bool classof(const Metadata *MD) {
432 return MD->getMetadataID() == ConstantAsMetadataKind;
433 }
434};
435
436class LocalAsMetadata : public ValueAsMetadata {
437 friend class ValueAsMetadata;
438
439 LocalAsMetadata(Value *Local)
440 : ValueAsMetadata(LocalAsMetadataKind, Local) {
441 assert(!isa<Constant>(Local) && "Expected local value");
442 }
443
444public:
445 static LocalAsMetadata *get(Value *Local) {
446 return ValueAsMetadata::getLocal(Local);
447 }
448
449 static LocalAsMetadata *getIfExists(Value *Local) {
450 return ValueAsMetadata::getLocalIfExists(Local);
451 }
452
453 static bool classof(const Metadata *MD) {
454 return MD->getMetadataID() == LocalAsMetadataKind;
455 }
456};
457
458/// Transitional API for extracting constants from Metadata.
459///
460/// This namespace contains transitional functions for metadata that points to
461/// \a Constants.
462///
463/// In prehistory -- when metadata was a subclass of \a Value -- \a MDNode
464/// operands could refer to any \a Value. There's was a lot of code like this:
465///
466/// \code
467/// MDNode *N = ...;
468/// auto *CI = dyn_cast<ConstantInt>(N->getOperand(2));
469/// \endcode
470///
471/// Now that \a Value and \a Metadata are in separate hierarchies, maintaining
472/// the semantics for \a isa(), \a cast(), \a dyn_cast() (etc.) requires three
473/// steps: cast in the \a Metadata hierarchy, extraction of the \a Value, and
474/// cast in the \a Value hierarchy. Besides creating boiler-plate, this
475/// requires subtle control flow changes.
476///
477/// The end-goal is to create a new type of metadata, called (e.g.) \a MDInt,
478/// so that metadata can refer to numbers without traversing a bridge to the \a
479/// Value hierarchy. In this final state, the code above would look like this:
480///
481/// \code
482/// MDNode *N = ...;
483/// auto *MI = dyn_cast<MDInt>(N->getOperand(2));
484/// \endcode
485///
486/// The API in this namespace supports the transition. \a MDInt doesn't exist
487/// yet, and even once it does, changing each metadata schema to use it is its
488/// own mini-project. In the meantime this API prevents us from introducing
489/// complex and bug-prone control flow that will disappear in the end. In
490/// particular, the above code looks like this:
491///
492/// \code
493/// MDNode *N = ...;
494/// auto *CI = mdconst::dyn_extract<ConstantInt>(N->getOperand(2));
495/// \endcode
496///
497/// The full set of provided functions includes:
498///
499/// mdconst::hasa <=> isa
500/// mdconst::extract <=> cast
501/// mdconst::extract_or_null <=> cast_or_null
502/// mdconst::dyn_extract <=> dyn_cast
503/// mdconst::dyn_extract_or_null <=> dyn_cast_or_null
504///
505/// The target of the cast must be a subclass of \a Constant.
506namespace mdconst {
507
508namespace detail {
509
510template <class T> T &make();
511template <class T, class Result> struct HasDereference {
512 using Yes = char[1];
513 using No = char[2];
514 template <size_t N> struct SFINAE {};
515
516 template <class U, class V>
517 static Yes &hasDereference(SFINAE<sizeof(static_cast<V>(*make<U>()))> * = 0);
518 template <class U, class V> static No &hasDereference(...);
519
520 static const bool value =
521 sizeof(hasDereference<T, Result>(nullptr)) == sizeof(Yes);
522};
523template <class V, class M> struct IsValidPointer {
524 static const bool value = std::is_base_of<Constant, V>::value &&
525 HasDereference<M, const Metadata &>::value;
526};
527template <class V, class M> struct IsValidReference {
528 static const bool value = std::is_base_of<Constant, V>::value &&
529 std::is_convertible<M, const Metadata &>::value;
530};
531
532} // end namespace detail
533
534/// Check whether Metadata has a Value.
535///
536/// As an analogue to \a isa(), check whether \c MD has an \a Value inside of
537/// type \c X.
538template <class X, class Y>
539inline std::enable_if_t<detail::IsValidPointer<X, Y>::value, bool>
540hasa(Y &&MD) {
541 assert(MD && "Null pointer sent into hasa");
542 if (auto *V = dyn_cast<ConstantAsMetadata>(MD))
543 return isa<X>(V->getValue());
544 return false;
545}
546template <class X, class Y>
547inline std::enable_if_t<detail::IsValidReference<X, Y &>::value, bool>
548hasa(Y &MD) {
549 return hasa(&MD);
550}
551
552/// Extract a Value from Metadata.
553///
554/// As an analogue to \a cast(), extract the \a Value subclass \c X from \c MD.
555template <class X, class Y>
556inline std::enable_if_t<detail::IsValidPointer<X, Y>::value, X *>
557extract(Y &&MD) {
558 return cast<X>(cast<ConstantAsMetadata>(MD)->getValue());
559}
560template <class X, class Y>
561inline std::enable_if_t<detail::IsValidReference<X, Y &>::value, X *>
562extract(Y &MD) {
563 return extract(&MD);
564}
565
566/// Extract a Value from Metadata, allowing null.
567///
568/// As an analogue to \a cast_or_null(), extract the \a Value subclass \c X
569/// from \c MD, allowing \c MD to be null.
570template <class X, class Y>
571inline std::enable_if_t<detail::IsValidPointer<X, Y>::value, X *>
572extract_or_null(Y &&MD) {
573 if (auto *V = cast_or_null<ConstantAsMetadata>(MD))
574 return cast<X>(V->getValue());
575 return nullptr;
576}
577
578/// Extract a Value from Metadata, if any.
579///
580/// As an analogue to \a dyn_cast_or_null(), extract the \a Value subclass \c X
581/// from \c MD, return null if \c MD doesn't contain a \a Value or if the \a
582/// Value it does contain is of the wrong subclass.
583template <class X, class Y>
584inline std::enable_if_t<detail::IsValidPointer<X, Y>::value, X *>
585dyn_extract(Y &&MD) {
586 if (auto *V = dyn_cast<ConstantAsMetadata>(MD))
587 return dyn_cast<X>(V->getValue());
588 return nullptr;
589}
590
591/// Extract a Value from Metadata, if any, allowing null.
592///
593/// As an analogue to \a dyn_cast_or_null(), extract the \a Value subclass \c X
594/// from \c MD, return null if \c MD doesn't contain a \a Value or if the \a
595/// Value it does contain is of the wrong subclass, allowing \c MD to be null.
596template <class X, class Y>
597inline std::enable_if_t<detail::IsValidPointer<X, Y>::value, X *>
598dyn_extract_or_null(Y &&MD) {
599 if (auto *V = dyn_cast_or_null<ConstantAsMetadata>(MD))
600 return dyn_cast<X>(V->getValue());
601 return nullptr;
602}
603
604} // end namespace mdconst
605
606//===----------------------------------------------------------------------===//
607/// A single uniqued string.
608///
609/// These are used to efficiently contain a byte sequence for metadata.
610/// MDString is always unnamed.
611class MDString : public Metadata {
612 friend class StringMapEntryStorage<MDString>;
613
614 StringMapEntry<MDString> *Entry = nullptr;
615
616 MDString() : Metadata(MDStringKind, Uniqued) {}
617
618public:
619 MDString(const MDString &) = delete;
620 MDString &operator=(MDString &&) = delete;
621 MDString &operator=(const MDString &) = delete;
622
623 static MDString *get(LLVMContext &Context, StringRef Str);
624 static MDString *get(LLVMContext &Context, const char *Str) {
625 return get(Context, Str ? StringRef(Str) : StringRef());
626 }
627
628 StringRef getString() const;
629
630 unsigned getLength() const { return (unsigned)getString().size(); }
631
632 using iterator = StringRef::iterator;
633
634 /// Pointer to the first byte of the string.
635 iterator begin() const { return getString().begin(); }
636
637 /// Pointer to one byte past the end of the string.
638 iterator end() const { return getString().end(); }
639
640 const unsigned char *bytes_begin() const { return getString().bytes_begin(); }
641 const unsigned char *bytes_end() const { return getString().bytes_end(); }
642
643 /// Methods for support type inquiry through isa, cast, and dyn_cast.
644 static bool classof(const Metadata *MD) {
645 return MD->getMetadataID() == MDStringKind;
646 }
647};
648
649/// A collection of metadata nodes that might be associated with a
650/// memory access used by the alias-analysis infrastructure.
651struct AAMDNodes {
652 explicit AAMDNodes() = default;
653 explicit AAMDNodes(MDNode *T, MDNode *TS, MDNode *S, MDNode *N)
654 : TBAA(T), TBAAStruct(TS), Scope(S), NoAlias(N) {}
655
656 bool operator==(const AAMDNodes &A) const {
657 return TBAA == A.TBAA && TBAAStruct == A.TBAAStruct && Scope == A.Scope &&
658 NoAlias == A.NoAlias;
659 }
660
661 bool operator!=(const AAMDNodes &A) const { return !(*this == A); }
662
663 explicit operator bool() const {
664 return TBAA || TBAAStruct || Scope || NoAlias;
665 }
666
667 /// The tag for type-based alias analysis.
668 MDNode *TBAA = nullptr;
669
670 /// The tag for type-based alias analysis (tbaa struct).
671 MDNode *TBAAStruct = nullptr;
672
673 /// The tag for alias scope specification (used with noalias).
674 MDNode *Scope = nullptr;
675
676 /// The tag specifying the noalias scope.
677 MDNode *NoAlias = nullptr;
678
679 // Shift tbaa Metadata node to start off bytes later
680 static MDNode *ShiftTBAA(MDNode *M, size_t off);
681
682 // Shift tbaa.struct Metadata node to start off bytes later
683 static MDNode *ShiftTBAAStruct(MDNode *M, size_t off);
684
685 /// Given two sets of AAMDNodes that apply to the same pointer,
686 /// give the best AAMDNodes that are compatible with both (i.e. a set of
687 /// nodes whose allowable aliasing conclusions are a subset of those
688 /// allowable by both of the inputs). However, for efficiency
689 /// reasons, do not create any new MDNodes.
690 AAMDNodes intersect(const AAMDNodes &Other) {
691 AAMDNodes Result;
692 Result.TBAA = Other.TBAA == TBAA ? TBAA : nullptr;
693 Result.TBAAStruct = Other.TBAAStruct == TBAAStruct ? TBAAStruct : nullptr;
694 Result.Scope = Other.Scope == Scope ? Scope : nullptr;
695 Result.NoAlias = Other.NoAlias == NoAlias ? NoAlias : nullptr;
696 return Result;
697 }
698
699 /// Create a new AAMDNode that describes this AAMDNode after applying a
700 /// constant offset to the start of the pointer
701 AAMDNodes shift(size_t Offset) {
702 AAMDNodes Result;
703 Result.TBAA = TBAA ? ShiftTBAA(TBAA, Offset) : nullptr;
704 Result.TBAAStruct =
705 TBAAStruct ? ShiftTBAAStruct(TBAAStruct, Offset) : nullptr;
706 Result.Scope = Scope;
707 Result.NoAlias = NoAlias;
708 return Result;
709 }
710};
711
712// Specialize DenseMapInfo for AAMDNodes.
713template<>
714struct DenseMapInfo<AAMDNodes> {
715 static inline AAMDNodes getEmptyKey() {
716 return AAMDNodes(DenseMapInfo<MDNode *>::getEmptyKey(),
717 nullptr, nullptr, nullptr);
718 }
719
720 static inline AAMDNodes getTombstoneKey() {
721 return AAMDNodes(DenseMapInfo<MDNode *>::getTombstoneKey(),
722 nullptr, nullptr, nullptr);
723 }
724
725 static unsigned getHashValue(const AAMDNodes &Val) {
726 return DenseMapInfo<MDNode *>::getHashValue(Val.TBAA) ^
727 DenseMapInfo<MDNode *>::getHashValue(Val.TBAAStruct) ^
728 DenseMapInfo<MDNode *>::getHashValue(Val.Scope) ^
729 DenseMapInfo<MDNode *>::getHashValue(Val.NoAlias);
730 }
731
732 static bool isEqual(const AAMDNodes &LHS, const AAMDNodes &RHS) {
733 return LHS == RHS;
734 }
735};
736
737/// Tracking metadata reference owned by Metadata.
738///
739/// Similar to \a TrackingMDRef, but it's expected to be owned by an instance
740/// of \a Metadata, which has the option of registering itself for callbacks to
741/// re-unique itself.
742///
743/// In particular, this is used by \a MDNode.
744class MDOperand {
745 Metadata *MD = nullptr;
746
747public:
748 MDOperand() = default;
749 MDOperand(MDOperand &&) = delete;
750 MDOperand(const MDOperand &) = delete;
751 MDOperand &operator=(MDOperand &&) = delete;
752 MDOperand &operator=(const MDOperand &) = delete;
753 ~MDOperand() { untrack(); }
754
755 Metadata *get() const { return MD; }
756 operator Metadata *() const { return get(); }
757 Metadata *operator->() const { return get(); }
758 Metadata &operator*() const { return *get(); }
759
760 void reset() {
761 untrack();
762 MD = nullptr;
763 }
764 void reset(Metadata *MD, Metadata *Owner) {
765 untrack();
766 this->MD = MD;
767 track(Owner);
768 }
769
770private:
771 void track(Metadata *Owner) {
772 if (MD) {
773 if (Owner)
774 MetadataTracking::track(this, *MD, *Owner);
775 else
776 MetadataTracking::track(MD);
777 }
778 }
779
780 void untrack() {
781 assert(static_cast<void *>(this) == &MD && "Expected same address");
782 if (MD)
783 MetadataTracking::untrack(MD);
784 }
785};
786
787template <> struct simplify_type<MDOperand> {
788 using SimpleType = Metadata *;
789
790 static SimpleType getSimplifiedValue(MDOperand &MD) { return MD.get(); }
791};
792
793template <> struct simplify_type<const MDOperand> {
794 using SimpleType = Metadata *;
795
796 static SimpleType getSimplifiedValue(const MDOperand &MD) { return MD.get(); }
797};
798
799/// Pointer to the context, with optional RAUW support.
800///
801/// Either a raw (non-null) pointer to the \a LLVMContext, or an owned pointer
802/// to \a ReplaceableMetadataImpl (which has a reference to \a LLVMContext).
803class ContextAndReplaceableUses {
804 PointerUnion<LLVMContext *, ReplaceableMetadataImpl *> Ptr;
805
806public:
807 ContextAndReplaceableUses(LLVMContext &Context) : Ptr(&Context) {}
808 ContextAndReplaceableUses(
809 std::unique_ptr<ReplaceableMetadataImpl> ReplaceableUses)
810 : Ptr(ReplaceableUses.release()) {
811 assert(getReplaceableUses() && "Expected non-null replaceable uses");
812 }
813 ContextAndReplaceableUses() = delete;
814 ContextAndReplaceableUses(ContextAndReplaceableUses &&) = delete;
815 ContextAndReplaceableUses(const ContextAndReplaceableUses &) = delete;
816 ContextAndReplaceableUses &operator=(ContextAndReplaceableUses &&) = delete;
817 ContextAndReplaceableUses &
818 operator=(const ContextAndReplaceableUses &) = delete;
819 ~ContextAndReplaceableUses() { delete getReplaceableUses(); }
820
821 operator LLVMContext &() { return getContext(); }
822
823 /// Whether this contains RAUW support.
824 bool hasReplaceableUses() const {
825 return Ptr.is<ReplaceableMetadataImpl *>();
826 }
827
828 LLVMContext &getContext() const {
829 if (hasReplaceableUses())
830 return getReplaceableUses()->getContext();
831 return *Ptr.get<LLVMContext *>();
832 }
833
834 ReplaceableMetadataImpl *getReplaceableUses() const {
835 if (hasReplaceableUses())
836 return Ptr.get<ReplaceableMetadataImpl *>();
837 return nullptr;
838 }
839
840 /// Ensure that this has RAUW support, and then return it.
841 ReplaceableMetadataImpl *getOrCreateReplaceableUses() {
842 if (!hasReplaceableUses())
843 makeReplaceable(std::make_unique<ReplaceableMetadataImpl>(getContext()));
844 return getReplaceableUses();
845 }
846
847 /// Assign RAUW support to this.
848 ///
849 /// Make this replaceable, taking ownership of \c ReplaceableUses (which must
850 /// not be null).
851 void
852 makeReplaceable(std::unique_ptr<ReplaceableMetadataImpl> ReplaceableUses) {
853 assert(ReplaceableUses && "Expected non-null replaceable uses");
854 assert(&ReplaceableUses->getContext() == &getContext() &&
855 "Expected same context");
856 delete getReplaceableUses();
857 Ptr = ReplaceableUses.release();
858 }
859
860 /// Drop RAUW support.
861 ///
862 /// Cede ownership of RAUW support, returning it.
863 std::unique_ptr<ReplaceableMetadataImpl> takeReplaceableUses() {
864 assert(hasReplaceableUses() && "Expected to own replaceable uses");
865 std::unique_ptr<ReplaceableMetadataImpl> ReplaceableUses(
866 getReplaceableUses());
867 Ptr = &ReplaceableUses->getContext();
868 return ReplaceableUses;
869 }
870};
871
872struct TempMDNodeDeleter {
873 inline void operator()(MDNode *Node) const;
874};
875
876#define HANDLE_MDNODE_LEAF(CLASS) \
877 using Temp##CLASS = std::unique_ptr<CLASS, TempMDNodeDeleter>;
878#define HANDLE_MDNODE_BRANCH(CLASS) HANDLE_MDNODE_LEAF(CLASS)
879#include "llvm/IR/Metadata.def"
880
881/// Metadata node.
882///
883/// Metadata nodes can be uniqued, like constants, or distinct. Temporary
884/// metadata nodes (with full support for RAUW) can be used to delay uniquing
885/// until forward references are known. The basic metadata node is an \a
886/// MDTuple.
887///
888/// There is limited support for RAUW at construction time. At construction
889/// time, if any operand is a temporary node (or an unresolved uniqued node,
890/// which indicates a transitive temporary operand), the node itself will be
891/// unresolved. As soon as all operands become resolved, it will drop RAUW
892/// support permanently.
893///
894/// If an unresolved node is part of a cycle, \a resolveCycles() needs
895/// to be called on some member of the cycle once all temporary nodes have been
896/// replaced.
897class MDNode : public Metadata {
898 friend class ReplaceableMetadataImpl;
899 friend class LLVMContextImpl;
900
901 unsigned NumOperands;
902 unsigned NumUnresolved;
903
904 ContextAndReplaceableUses Context;
905
906protected:
907 MDNode(LLVMContext &Context, unsigned ID, StorageType Storage,
908 ArrayRef<Metadata *> Ops1, ArrayRef<Metadata *> Ops2 = None);
909 ~MDNode() = default;
910
911 void *operator new(size_t Size, unsigned NumOps);
912 void operator delete(void *Mem);
913
914 /// Required by std, but never called.
915 void operator delete(void *, unsigned) {
916 llvm_unreachable("Constructor throws?");
917 }
918
919 /// Required by std, but never called.
920 void operator delete(void *, unsigned, bool) {
921 llvm_unreachable("Constructor throws?");
922 }
923
924 void dropAllReferences();
925
926 MDOperand *mutable_begin() { return mutable_end() - NumOperands; }
927 MDOperand *mutable_end() { return reinterpret_cast<MDOperand *>(this); }
928
929 using mutable_op_range = iterator_range<MDOperand *>;
930
931 mutable_op_range mutable_operands() {
932 return mutable_op_range(mutable_begin(), mutable_end());
933 }
934
935public:
936 MDNode(const MDNode &) = delete;
937 void operator=(const MDNode &) = delete;
938 void *operator new(size_t) = delete;
939
940 static inline MDTuple *get(LLVMContext &Context, ArrayRef<Metadata *> MDs);
941 static inline MDTuple *getIfExists(LLVMContext &Context,
942 ArrayRef<Metadata *> MDs);
943 static inline MDTuple *getDistinct(LLVMContext &Context,
944 ArrayRef<Metadata *> MDs);
945 static inline TempMDTuple getTemporary(LLVMContext &Context,
946 ArrayRef<Metadata *> MDs);
947
948 /// Create a (temporary) clone of this.
949 TempMDNode clone() const;
950
951 /// Deallocate a node created by getTemporary.
952 ///
953 /// Calls \c replaceAllUsesWith(nullptr) before deleting, so any remaining
954 /// references will be reset.
955 static void deleteTemporary(MDNode *N);
956
957 LLVMContext &getContext() const { return Context.getContext(); }
958
959 /// Replace a specific operand.
960 void replaceOperandWith(unsigned I, Metadata *New);
961
962 /// Check if node is fully resolved.
963 ///
964 /// If \a isTemporary(), this always returns \c false; if \a isDistinct(),
965 /// this always returns \c true.
966 ///
967 /// If \a isUniqued(), returns \c true if this has already dropped RAUW
968 /// support (because all operands are resolved).
969 ///
970 /// As forward declarations are resolved, their containers should get
971 /// resolved automatically. However, if this (or one of its operands) is
972 /// involved in a cycle, \a resolveCycles() needs to be called explicitly.
973 bool isResolved() const { return !isTemporary() && !NumUnresolved; }
974
975 bool isUniqued() const { return Storage == Uniqued; }
976 bool isDistinct() const { return Storage == Distinct; }
977 bool isTemporary() const { return Storage == Temporary; }
978
979 /// RAUW a temporary.
980 ///
981 /// \pre \a isTemporary() must be \c true.
982 void replaceAllUsesWith(Metadata *MD) {
983 assert(isTemporary() && "Expected temporary node");
984 if (Context.hasReplaceableUses())
985 Context.getReplaceableUses()->replaceAllUsesWith(MD);
986 }
987
988 /// Resolve cycles.
989 ///
990 /// Once all forward declarations have been resolved, force cycles to be
991 /// resolved.
992 ///
993 /// \pre No operands (or operands' operands, etc.) have \a isTemporary().
994 void resolveCycles();
995
996 /// Resolve a unique, unresolved node.
997 void resolve();
998
999 /// Replace a temporary node with a permanent one.
1000 ///
1001 /// Try to create a uniqued version of \c N -- in place, if possible -- and
1002 /// return it. If \c N cannot be uniqued, return a distinct node instead.
1003 template <class T>
1004 static std::enable_if_t<std::is_base_of<MDNode, T>::value, T *>
1005 replaceWithPermanent(std::unique_ptr<T, TempMDNodeDeleter> N) {
1006 return cast<T>(N.release()->replaceWithPermanentImpl());
1007 }
1008
1009 /// Replace a temporary node with a uniqued one.
1010 ///
1011 /// Create a uniqued version of \c N -- in place, if possible -- and return
1012 /// it. Takes ownership of the temporary node.
1013 ///
1014 /// \pre N does not self-reference.
1015 template <class T>
1016 static std::enable_if_t<std::is_base_of<MDNode, T>::value, T *>
1017 replaceWithUniqued(std::unique_ptr<T, TempMDNodeDeleter> N) {
1018 return cast<T>(N.release()->replaceWithUniquedImpl());
1019 }
1020
1021 /// Replace a temporary node with a distinct one.
1022 ///
1023 /// Create a distinct version of \c N -- in place, if possible -- and return
1024 /// it. Takes ownership of the temporary node.
1025 template <class T>
1026 static std::enable_if_t<std::is_base_of<MDNode, T>::value, T *>
1027 replaceWithDistinct(std::unique_ptr<T, TempMDNodeDeleter> N) {
1028 return cast<T>(N.release()->replaceWithDistinctImpl());
1029 }
1030
1031private:
1032 MDNode *replaceWithPermanentImpl();
1033 MDNode *replaceWithUniquedImpl();
1034 MDNode *replaceWithDistinctImpl();
1035
1036protected:
1037 /// Set an operand.
1038 ///
1039 /// Sets the operand directly, without worrying about uniquing.
1040 void setOperand(unsigned I, Metadata *New);
1041
1042 void storeDistinctInContext();
1043 template <class T, class StoreT>
1044 static T *storeImpl(T *N, StorageType Storage, StoreT &Store);
1045 template <class T> static T *storeImpl(T *N, StorageType Storage);
1046
1047private:
1048 void handleChangedOperand(void *Ref, Metadata *New);
1049
1050 /// Drop RAUW support, if any.
1051 void dropReplaceableUses();
1052
1053 void resolveAfterOperandChange(Metadata *Old, Metadata *New);
1054 void decrementUnresolvedOperandCount();
1055 void countUnresolvedOperands();
1056
1057 /// Mutate this to be "uniqued".
1058 ///
1059 /// Mutate this so that \a isUniqued().
1060 /// \pre \a isTemporary().
1061 /// \pre already added to uniquing set.
1062 void makeUniqued();
1063
1064 /// Mutate this to be "distinct".
1065 ///
1066 /// Mutate this so that \a isDistinct().
1067 /// \pre \a isTemporary().
1068 void makeDistinct();
1069
1070 void deleteAsSubclass();
1071 MDNode *uniquify();
1072 void eraseFromStore();
1073
1074 template <class NodeTy> struct HasCachedHash;
1075 template <class NodeTy>
1076 static void dispatchRecalculateHash(NodeTy *N, std::true_type) {
1077 N->recalculateHash();
1078 }
1079 template <class NodeTy>
1080 static void dispatchRecalculateHash(NodeTy *, std::false_type) {}
1081 template <class NodeTy>
1082 static void dispatchResetHash(NodeTy *N, std::true_type) {
1083 N->setHash(0);
1084 }
1085 template <class NodeTy>
1086 static void dispatchResetHash(NodeTy *, std::false_type) {}
1087
1088public:
1089 using op_iterator = const MDOperand *;
1090 using op_range = iterator_range<op_iterator>;
1091
1092 op_iterator op_begin() const {
1093 return const_cast<MDNode *>(this)->mutable_begin();
1094 }
1095
1096 op_iterator op_end() const {
1097 return const_cast<MDNode *>(this)->mutable_end();
1098 }
1099
1100 op_range operands() const { return op_range(op_begin(), op_end()); }
1101
1102 const MDOperand &getOperand(unsigned I) const {
1103 assert(I < NumOperands && "Out of range");
1104 return op_begin()[I];
1105 }
1106
1107 /// Return number of MDNode operands.
1108 unsigned getNumOperands() const { return NumOperands; }
1109
1110 /// Methods for support type inquiry through isa, cast, and dyn_cast:
1111 static bool classof(const Metadata *MD) {
1112 switch (MD->getMetadataID()) {
1113 default:
1114 return false;
1115#define HANDLE_MDNODE_LEAF(CLASS) \
1116 case CLASS##Kind: \
1117 return true;
1118#include "llvm/IR/Metadata.def"
1119 }
1120 }
1121
1122 /// Check whether MDNode is a vtable access.
1123 bool isTBAAVtableAccess() const;
1124
1125 /// Methods for metadata merging.
1126 static MDNode *concatenate(MDNode *A, MDNode *B);
1127 static MDNode *intersect(MDNode *A, MDNode *B);
1128 static MDNode *getMostGenericTBAA(MDNode *A, MDNode *B);
1129 static MDNode *getMostGenericFPMath(MDNode *A, MDNode *B);
1130 static MDNode *getMostGenericRange(MDNode *A, MDNode *B);
1131 static MDNode *getMostGenericAliasScope(MDNode *A, MDNode *B);
1132 static MDNode *getMostGenericAlignmentOrDereferenceable(MDNode *A, MDNode *B);
1133};
1134
1135/// Tuple of metadata.
1136///
1137/// This is the simple \a MDNode arbitrary tuple. Nodes are uniqued by
1138/// default based on their operands.
1139class MDTuple : public MDNode {
1140 friend class LLVMContextImpl;
1141 friend class MDNode;
1142
1143 MDTuple(LLVMContext &C, StorageType Storage, unsigned Hash,
1144 ArrayRef<Metadata *> Vals)
1145 : MDNode(C, MDTupleKind, Storage, Vals) {
1146 setHash(Hash);
1147 }
1148
1149 ~MDTuple() { dropAllReferences(); }
1150
1151 void setHash(unsigned Hash) { SubclassData32 = Hash; }
1152 void recalculateHash();
1153
1154 static MDTuple *getImpl(LLVMContext &Context, ArrayRef<Metadata *> MDs,
1155 StorageType Storage, bool ShouldCreate = true);
1156
1157 TempMDTuple cloneImpl() const {
1158 return getTemporary(getContext(), SmallVector<Metadata *, 4>(operands()));
1159 }
1160
1161public:
1162 /// Get the hash, if any.
1163 unsigned getHash() const { return SubclassData32; }
1164
1165 static MDTuple *get(LLVMContext &Context, ArrayRef<Metadata *> MDs) {
1166 return getImpl(Context, MDs, Uniqued);
1167 }
1168
1169 static MDTuple *getIfExists(LLVMContext &Context, ArrayRef<Metadata *> MDs) {
1170 return getImpl(Context, MDs, Uniqued, /* ShouldCreate */ false);
1171 }
1172
1173 /// Return a distinct node.
1174 ///
1175 /// Return a distinct node -- i.e., a node that is not uniqued.
1176 static MDTuple *getDistinct(LLVMContext &Context, ArrayRef<Metadata *> MDs) {
1177 return getImpl(Context, MDs, Distinct);
1178 }
1179
1180 /// Return a temporary node.
1181 ///
1182 /// For use in constructing cyclic MDNode structures. A temporary MDNode is
1183 /// not uniqued, may be RAUW'd, and must be manually deleted with
1184 /// deleteTemporary.
1185 static TempMDTuple getTemporary(LLVMContext &Context,
1186 ArrayRef<Metadata *> MDs) {
1187 return TempMDTuple(getImpl(Context, MDs, Temporary));
1188 }
1189
1190 /// Return a (temporary) clone of this.
1191 TempMDTuple clone() const { return cloneImpl(); }
1192
1193 static bool classof(const Metadata *MD) {
1194 return MD->getMetadataID() == MDTupleKind;
1195 }
1196};
1197
1198MDTuple *MDNode::get(LLVMContext &Context, ArrayRef<Metadata *> MDs) {
1199 return MDTuple::get(Context, MDs);
1200}
1201
1202MDTuple *MDNode::getIfExists(LLVMContext &Context, ArrayRef<Metadata *> MDs) {
1203 return MDTuple::getIfExists(Context, MDs);
1204}
1205
1206MDTuple *MDNode::getDistinct(LLVMContext &Context, ArrayRef<Metadata *> MDs) {
1207 return MDTuple::getDistinct(Context, MDs);
1208}
1209
1210TempMDTuple MDNode::getTemporary(LLVMContext &Context,
1211 ArrayRef<Metadata *> MDs) {
1212 return MDTuple::getTemporary(Context, MDs);
1213}
1214
1215void TempMDNodeDeleter::operator()(MDNode *Node) const {
1216 MDNode::deleteTemporary(Node);
1217}
1218
1219/// This is a simple wrapper around an MDNode which provides a higher-level
1220/// interface by hiding the details of how alias analysis information is encoded
1221/// in its operands.
1222class AliasScopeNode {
1223 const MDNode *Node = nullptr;
1224
1225public:
1226 AliasScopeNode() = default;
1227 explicit AliasScopeNode(const MDNode *N) : Node(N) {}
1228
1229 /// Get the MDNode for this AliasScopeNode.
1230 const MDNode *getNode() const { return Node; }
1231
1232 /// Get the MDNode for this AliasScopeNode's domain.
1233 const MDNode *getDomain() const {
1234 if (Node->getNumOperands() < 2)
1235 return nullptr;
1236 return dyn_cast_or_null<MDNode>(Node->getOperand(1));
1237 }
1238 StringRef getName() const {
1239 if (Node->getNumOperands() > 2)
1240 if (MDString *N = dyn_cast_or_null<MDString>(Node->getOperand(2)))
1241 return N->getString();
1242 return StringRef();
1243 }
1244};
1245
1246/// Typed iterator through MDNode operands.
1247///
1248/// An iterator that transforms an \a MDNode::iterator into an iterator over a
1249/// particular Metadata subclass.
1250template <class T> class TypedMDOperandIterator {
1251 MDNode::op_iterator I = nullptr;
1252
1253public:
1254 using iterator_category = std::input_iterator_tag;
1255 using value_type = T *;
1256 using difference_type = std::ptrdiff_t;
1257 using pointer = void;
1258 using reference = T *;
1259
1260 TypedMDOperandIterator() = default;
1261 explicit TypedMDOperandIterator(MDNode::op_iterator I) : I(I) {}
1262
1263 T *operator*() const { return cast_or_null<T>(*I); }
1264
1265 TypedMDOperandIterator &operator++() {
1266 ++I;
1267 return *this;
1268 }
1269
1270 TypedMDOperandIterator operator++(int) {
1271 TypedMDOperandIterator Temp(*this);
1272 ++I;
1273 return Temp;
1274 }
1275
1276 bool operator==(const TypedMDOperandIterator &X) const { return I == X.I; }
1277 bool operator!=(const TypedMDOperandIterator &X) const { return I != X.I; }
1278};
1279
1280/// Typed, array-like tuple of metadata.
1281///
1282/// This is a wrapper for \a MDTuple that makes it act like an array holding a
1283/// particular type of metadata.
1284template <class T> class MDTupleTypedArrayWrapper {
1285 const MDTuple *N = nullptr;
1286
1287public:
1288 MDTupleTypedArrayWrapper() = default;
1289 MDTupleTypedArrayWrapper(const MDTuple *N) : N(N) {}
1290
1291 template <class U>
1292 MDTupleTypedArrayWrapper(
1293 const MDTupleTypedArrayWrapper<U> &Other,
1294 std::enable_if_t<std::is_convertible<U *, T *>::value> * = nullptr)
1295 : N(Other.get()) {}
1296
1297 template <class U>
1298 explicit MDTupleTypedArrayWrapper(
1299 const MDTupleTypedArrayWrapper<U> &Other,
1300 std::enable_if_t<!std::is_convertible<U *, T *>::value> * = nullptr)
1301 : N(Other.get()) {}
1302
1303 explicit operator bool() const { return get(); }
1304 explicit operator MDTuple *() const { return get(); }
1305
1306 MDTuple *get() const { return const_cast<MDTuple *>(N); }
1307 MDTuple *operator->() const { return get(); }
1308 MDTuple &operator*() const { return *get(); }
1309
1310 // FIXME: Fix callers and remove condition on N.
1311 unsigned size() const { return N ? N->getNumOperands() : 0u; }
1312 bool empty() const { return N ? N->getNumOperands() == 0 : true; }
1313 T *operator[](unsigned I) const { return cast_or_null<T>(N->getOperand(I)); }
1314
1315 // FIXME: Fix callers and remove condition on N.
1316 using iterator = TypedMDOperandIterator<T>;
1317
1318 iterator begin() const { return N ? iterator(N->op_begin()) : iterator(); }
1319 iterator end() const { return N ? iterator(N->op_end()) : iterator(); }
1320};
1321
1322#define HANDLE_METADATA(CLASS) \
1323 using CLASS##Array = MDTupleTypedArrayWrapper<CLASS>;
1324#include "llvm/IR/Metadata.def"
1325
1326/// Placeholder metadata for operands of distinct MDNodes.
1327///
1328/// This is a lightweight placeholder for an operand of a distinct node. It's
1329/// purpose is to help track forward references when creating a distinct node.
1330/// This allows distinct nodes involved in a cycle to be constructed before
1331/// their operands without requiring a heavyweight temporary node with
1332/// full-blown RAUW support.
1333///
1334/// Each placeholder supports only a single MDNode user. Clients should pass
1335/// an ID, retrieved via \a getID(), to indicate the "real" operand that this
1336/// should be replaced with.
1337///
1338/// While it would be possible to implement move operators, they would be
1339/// fairly expensive. Leave them unimplemented to discourage their use
1340/// (clients can use std::deque, std::list, BumpPtrAllocator, etc.).
1341class DistinctMDOperandPlaceholder : public Metadata {
1342 friend class MetadataTracking;
1343
1344 Metadata **Use = nullptr;
1345
1346public:
1347 explicit DistinctMDOperandPlaceholder(unsigned ID)
1348 : Metadata(DistinctMDOperandPlaceholderKind, Distinct) {
1349 SubclassData32 = ID;
1350 }
1351
1352 DistinctMDOperandPlaceholder() = delete;
1353 DistinctMDOperandPlaceholder(DistinctMDOperandPlaceholder &&) = delete;
1354 DistinctMDOperandPlaceholder(const DistinctMDOperandPlaceholder &) = delete;
1355
1356 ~DistinctMDOperandPlaceholder() {
1357 if (Use)
1358 *Use = nullptr;
1359 }
1360
1361 unsigned getID() const { return SubclassData32; }
1362
1363 /// Replace the use of this with MD.
1364 void replaceUseWith(Metadata *MD) {
1365 if (!Use)
1366 return;
1367 *Use = MD;
1368
1369 if (*Use)
1370 MetadataTracking::track(*Use);
1371
1372 Metadata *T = cast<Metadata>(this);
1373 MetadataTracking::untrack(T);
1374 assert(!Use && "Use is still being tracked despite being untracked!");
1375 }
1376};
1377
1378//===----------------------------------------------------------------------===//
1379/// A tuple of MDNodes.
1380///
1381/// Despite its name, a NamedMDNode isn't itself an MDNode.
1382///
1383/// NamedMDNodes are named module-level entities that contain lists of MDNodes.
1384///
1385/// It is illegal for a NamedMDNode to appear as an operand of an MDNode.
1386class NamedMDNode : public ilist_node<NamedMDNode> {
1387 friend class LLVMContextImpl;
1388 friend class Module;
1389
1390 std::string Name;
1391 Module *Parent = nullptr;
1392 void *Operands; // SmallVector<TrackingMDRef, 4>
1393
1394 void setParent(Module *M) { Parent = M; }
1395
1396 explicit NamedMDNode(const Twine &N);
1397
1398 template <class T1, class T2> class op_iterator_impl {
1399 friend class NamedMDNode;
1400
1401 const NamedMDNode *Node = nullptr;
1402 unsigned Idx = 0;
1403
1404 op_iterator_impl(const NamedMDNode *N, unsigned i) : Node(N), Idx(i) {}
1405
1406 public:
1407 using iterator_category = std::bidirectional_iterator_tag;
1408 using value_type = T2;
1409 using difference_type = std::ptrdiff_t;
1410 using pointer = value_type *;
1411 using reference = value_type &;
1412
1413 op_iterator_impl() = default;
1414
1415 bool operator==(const op_iterator_impl &o) const { return Idx == o.Idx; }
1416 bool operator!=(const op_iterator_impl &o) const { return Idx != o.Idx; }
1417
1418 op_iterator_impl &operator++() {
1419 ++Idx;
1420 return *this;
1421 }
1422
1423 op_iterator_impl operator++(int) {
1424 op_iterator_impl tmp(*this);
1425 operator++();
1426 return tmp;
1427 }
1428
1429 op_iterator_impl &operator--() {
1430 --Idx;
1431 return *this;
1432 }
1433
1434 op_iterator_impl operator--(int) {
1435 op_iterator_impl tmp(*this);
1436 operator--();
1437 return tmp;
1438 }
1439
1440 T1 operator*() const { return Node->getOperand(Idx); }
1441 };
1442
1443public:
1444 NamedMDNode(const NamedMDNode &) = delete;
1445 ~NamedMDNode();
1446
1447 /// Drop all references and remove the node from parent module.
1448 void eraseFromParent();
1449
1450 /// Remove all uses and clear node vector.
1451 void dropAllReferences() { clearOperands(); }
1452 /// Drop all references to this node's operands.
1453 void clearOperands();
1454
1455 /// Get the module that holds this named metadata collection.
1456 inline Module *getParent() { return Parent; }
1457 inline const Module *getParent() const { return Parent; }
1458
1459 MDNode *getOperand(unsigned i) const;
1460 unsigned getNumOperands() const;
1461 void addOperand(MDNode *M);
1462 void setOperand(unsigned I, MDNode *New);
1463 StringRef getName() const;
1464 void print(raw_ostream &ROS, bool IsForDebug = false) const;
1465 void print(raw_ostream &ROS, ModuleSlotTracker &MST,
1466 bool IsForDebug = false) const;
1467 void dump() const;
1468
1469 // ---------------------------------------------------------------------------
1470 // Operand Iterator interface...
1471 //
1472 using op_iterator = op_iterator_impl<MDNode *, MDNode>;
1473
1474 op_iterator op_begin() { return op_iterator(this, 0); }
1475 op_iterator op_end() { return op_iterator(this, getNumOperands()); }
1476
1477 using const_op_iterator = op_iterator_impl<const MDNode *, MDNode>;
1478
1479 const_op_iterator op_begin() const { return const_op_iterator(this, 0); }
1480 const_op_iterator op_end() const { return const_op_iterator(this, getNumOperands()); }
1481
1482 inline iterator_range<op_iterator> operands() {
1483 return make_range(op_begin(), op_end());
1484 }
1485 inline iterator_range<const_op_iterator> operands() const {
1486 return make_range(op_begin(), op_end());
1487 }
1488};
1489
1490// Create wrappers for C Binding types (see CBindingWrapping.h).
1491DEFINE_ISA_CONVERSION_FUNCTIONS(NamedMDNode, LLVMNamedMDNodeRef)
1492
1493} // end namespace llvm
1494
1495#endif // LLVM_IR_METADATA_H
1496