//===- llvm/IR/Metadata.h - Metadata definitions ----------------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
/// @file
/// This file contains the declarations for metadata subclasses.
/// They represent the different flavors of metadata that live in LLVM.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_IR_METADATA_H
#define LLVM_IR_METADATA_H
#include "llvm/ADT/ArrayRef.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/DenseMapInfo.h"
#include "llvm/ADT/None.h"
#include "llvm/ADT/PointerUnion.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/ADT/ilist_node.h"
#include "llvm/ADT/iterator_range.h"
#include "llvm/IR/Constant.h"
#include "llvm/IR/LLVMContext.h"
#include "llvm/IR/Value.h"
#include "llvm/Support/CBindingWrapping.h"
#include "llvm/Support/Casting.h"
#include "llvm/Support/ErrorHandling.h"
#include <cassert>
#include <cstddef>
#include <cstdint>
#include <iterator>
#include <memory>
#include <string>
#include <type_traits>
#include <utility>
namespace llvm {
class Module;
class ModuleSlotTracker;
class raw_ostream;
class Type;
enum LLVMConstants : uint32_t {
DEBUG_METADATA_VERSION = 3 // Current debug info version number.
};
/// \brief Root of the metadata hierarchy.
///
/// This is a root class for typeless data in the IR.
class Metadata {
friend class ReplaceableMetadataImpl;
/// \brief RTTI.
const unsigned char SubclassID;
protected:
/// \brief Active type of storage.
enum StorageType { Uniqued, Distinct, Temporary };
/// \brief Storage flag for non-uniqued, otherwise unowned, metadata.
unsigned char Storage;
// TODO: expose remaining bits to subclasses.
unsigned short SubclassData16 = 0;
unsigned SubclassData32 = 0;
public:
enum MetadataKind {
#define HANDLE_METADATA_LEAF(CLASS) CLASS##Kind,
#include "llvm/IR/Metadata.def"
};
protected:
Metadata(unsigned ID, StorageType Storage)
: SubclassID(ID), Storage(Storage) {
static_assert(sizeof(*this) == 8, "Metadata fields poorly packed");
}
~Metadata() = default;
/// \brief Default handling of a changed operand, which asserts.
///
/// If subclasses pass themselves in as owners to a tracking node reference,
/// they must provide an implementation of this method.
void handleChangedOperand(void *, Metadata *) {
llvm_unreachable("Unimplemented in Metadata subclass");
}
public:
unsigned getMetadataID() const { return SubclassID; }
/// \brief User-friendly dump.
///
/// If \c M is provided, metadata nodes will be numbered canonically;
/// otherwise, pointer addresses are substituted.
///
/// Note: this uses an explicit overload instead of default arguments so that
/// the nullptr version is easy to call from a debugger.
///
/// @{
void dump() const;
void dump(const Module *M) const;
/// @}
/// \brief Print.
///
/// Prints definition of \c this.
///
/// If \c M is provided, metadata nodes will be numbered canonically;
/// otherwise, pointer addresses are substituted.
/// @{
void print(raw_ostream &OS, const Module *M = nullptr,
bool IsForDebug = false) const;
void print(raw_ostream &OS, ModuleSlotTracker &MST, const Module *M = nullptr,
bool IsForDebug = false) const;
/// @}
/// \brief Print as operand.
///
/// Prints reference of \c this.
///
/// If \c M is provided, metadata nodes will be numbered canonically;
/// otherwise, pointer addresses are substituted.
/// @{
void printAsOperand(raw_ostream &OS, const Module *M = nullptr) const;
void printAsOperand(raw_ostream &OS, ModuleSlotTracker &MST,
const Module *M = nullptr) const;
/// @}
};
// Create wrappers for C Binding types (see CBindingWrapping.h).
DEFINE_ISA_CONVERSION_FUNCTIONS(Metadata, LLVMMetadataRef)
// Specialized opaque metadata conversions.
inline Metadata **unwrap(LLVMMetadataRef *MDs) {
return reinterpret_cast<Metadata**>(MDs);
}
#define HANDLE_METADATA(CLASS) class CLASS;
#include "llvm/IR/Metadata.def"
// Provide specializations of isa so that we don't need definitions of
// subclasses to see if the metadata is a subclass.
#define HANDLE_METADATA_LEAF(CLASS) \
template <> struct isa_impl<CLASS, Metadata> { \
static inline bool doit(const Metadata &MD) { \
return MD.getMetadataID() == Metadata::CLASS##Kind; \
} \
};
#include "llvm/IR/Metadata.def"
inline raw_ostream &operator<<(raw_ostream &OS, const Metadata &MD) {
MD.print(OS);
return OS;
}
/// \brief Metadata wrapper in the Value hierarchy.
///
/// A member of the \a Value hierarchy to represent a reference to metadata.
/// This allows, e.g., instrinsics to have metadata as operands.
///
/// Notably, this is the only thing in either hierarchy that is allowed to
/// reference \a LocalAsMetadata.
class MetadataAsValue : public Value {
friend class ReplaceableMetadataImpl;
friend class LLVMContextImpl;
Metadata *MD;
MetadataAsValue(Type *Ty, Metadata *MD);
/// \brief Drop use of metadata (during teardown).
void dropUse() { MD = nullptr; }
public:
~MetadataAsValue();
static MetadataAsValue *get(LLVMContext &Context, Metadata *MD);
static MetadataAsValue *getIfExists(LLVMContext &Context, Metadata *MD);
Metadata *getMetadata() const { return MD; }
static bool classof(const Value *V) {
return V->getValueID() == MetadataAsValueVal;
}
private:
void handleChangedMetadata(Metadata *MD);
void track();
void untrack();
};
/// \brief API for tracking metadata references through RAUW and deletion.
///
/// Shared API for updating \a Metadata pointers in subclasses that support
/// RAUW.
///
/// This API is not meant to be used directly. See \a TrackingMDRef for a
/// user-friendly tracking reference.
class MetadataTracking {
public:
/// \brief Track the reference to metadata.
///
/// Register \c MD with \c *MD, if the subclass supports tracking. If \c *MD
/// gets RAUW'ed, \c MD will be updated to the new address. If \c *MD gets
/// deleted, \c MD will be set to \c nullptr.
///
/// If tracking isn't supported, \c *MD will not change.
///
/// \return true iff tracking is supported by \c MD.
static bool track(Metadata *&MD) {
return track(&MD, *MD, static_cast<Metadata *>(nullptr));
}
/// \brief Track the reference to metadata for \a Metadata.
///
/// As \a track(Metadata*&), but with support for calling back to \c Owner to
/// tell it that its operand changed. This could trigger \c Owner being
/// re-uniqued.
static bool track(void *Ref, Metadata &MD, Metadata &Owner) {
return track(Ref, MD, &Owner);
}
/// \brief Track the reference to metadata for \a MetadataAsValue.
///
/// As \a track(Metadata*&), but with support for calling back to \c Owner to
/// tell it that its operand changed. This could trigger \c Owner being
/// re-uniqued.
static bool track(void *Ref, Metadata &MD, MetadataAsValue &Owner) {
return track(Ref, MD, &Owner);
}
/// \brief Stop tracking a reference to metadata.
///
/// Stops \c *MD from tracking \c MD.
static void untrack(Metadata *&MD) { untrack(&MD, *MD); }
static void untrack(void *Ref, Metadata &MD);
/// \brief Move tracking from one reference to another.
///
/// Semantically equivalent to \c untrack(MD) followed by \c track(New),
/// except that ownership callbacks are maintained.
///
/// Note: it is an error if \c *MD does not equal \c New.
///
/// \return true iff tracking is supported by \c MD.
static bool retrack(Metadata *&MD, Metadata *&New) {
return retrack(&MD, *MD, &New);
}
static bool retrack(void *Ref, Metadata &MD, void *New);
/// \brief Check whether metadata is replaceable.
static bool isReplaceable(const Metadata &MD);
using OwnerTy = PointerUnion<MetadataAsValue *, Metadata *>;
private:
/// \brief Track a reference to metadata for an owner.
///
/// Generalized version of tracking.
static bool track(void *Ref, Metadata &MD, OwnerTy Owner);
};
/// \brief Shared implementation of use-lists for replaceable metadata.
///
/// Most metadata cannot be RAUW'ed. This is a shared implementation of
/// use-lists and associated API for the two that support it (\a ValueAsMetadata
/// and \a TempMDNode).
class ReplaceableMetadataImpl {
friend class MetadataTracking;
public:
using OwnerTy = MetadataTracking::OwnerTy;
private:
LLVMContext &Context;
uint64_t NextIndex = 0;
SmallDenseMap<void *, std::pair<OwnerTy, uint64_t>, 4> UseMap;
public:
ReplaceableMetadataImpl(LLVMContext &Context) : Context(Context) {}
~ReplaceableMetadataImpl() {
assert(UseMap.empty() && "Cannot destroy in-use replaceable metadata");
}
LLVMContext &getContext() const { return Context; }
/// \brief Replace all uses of this with MD.
///
/// Replace all uses of this with \c MD, which is allowed to be null.
void replaceAllUsesWith(Metadata *MD);
/// \brief Resolve all uses of this.
///
/// Resolve all uses of this, turning off RAUW permanently. If \c
/// ResolveUsers, call \a MDNode::resolve() on any users whose last operand
/// is resolved.
void resolveAllUses(bool ResolveUsers = true);
private:
void addRef(void *Ref, OwnerTy Owner);
void dropRef(void *Ref);
void moveRef(void *Ref, void *New, const Metadata &MD);
/// Lazily construct RAUW support on MD.
///
/// If this is an unresolved MDNode, RAUW support will be created on-demand.
/// ValueAsMetadata always has RAUW support.
static ReplaceableMetadataImpl *getOrCreate(Metadata &MD);
/// Get RAUW support on MD, if it exists.
static ReplaceableMetadataImpl *getIfExists(Metadata &MD);
/// Check whether this node will support RAUW.
///
/// Returns \c true unless getOrCreate() would return null.
static bool isReplaceable(const Metadata &MD);
};
/// \brief Value wrapper in the Metadata hierarchy.
///
/// This is a custom value handle that allows other metadata to refer to
/// classes in the Value hierarchy.
///
/// Because of full uniquing support, each value is only wrapped by a single \a
/// ValueAsMetadata object, so the lookup maps are far more efficient than
/// those using ValueHandleBase.
class ValueAsMetadata : public Metadata, ReplaceableMetadataImpl {
friend class ReplaceableMetadataImpl;
friend class LLVMContextImpl;
Value *V;
/// \brief Drop users without RAUW (during teardown).
void dropUsers() {
ReplaceableMetadataImpl::resolveAllUses(/* ResolveUsers */ false);
}
protected:
ValueAsMetadata(unsigned ID, Value *V)
: Metadata(ID, Uniqued), ReplaceableMetadataImpl(V->getContext()), V(V) {
assert(V && "Expected valid value");
}
~ValueAsMetadata() = default;
public:
static ValueAsMetadata *get(Value *V);
static ConstantAsMetadata *getConstant(Value *C) {
return cast<ConstantAsMetadata>(get(C));
}
static LocalAsMetadata *getLocal(Value *Local) {
return cast<LocalAsMetadata>(get(Local));
}
static ValueAsMetadata *getIfExists(Value *V);
static ConstantAsMetadata *getConstantIfExists(Value *C) {
return cast_or_null<ConstantAsMetadata>(getIfExists(C));
}
static LocalAsMetadata *getLocalIfExists(Value *Local) {
return cast_or_null<LocalAsMetadata>(getIfExists(Local));
}
Value *getValue() const { return V; }
Type *getType() const { return V->getType(); }
LLVMContext &getContext() const { return V->getContext(); }
static void handleDeletion(Value *V);
static void handleRAUW(Value *From, Value *To);
protected:
/// \brief Handle collisions after \a Value::replaceAllUsesWith().
///
/// RAUW isn't supported directly for \a ValueAsMetadata, but if the wrapped
/// \a Value gets RAUW'ed and the target already exists, this is used to
/// merge the two metadata nodes.
void replaceAllUsesWith(Metadata *MD) {
ReplaceableMetadataImpl::replaceAllUsesWith(MD);
}
public:
static bool classof(const Metadata *MD) {
return MD->getMetadataID() == LocalAsMetadataKind ||
MD->getMetadataID() == ConstantAsMetadataKind;
}
};
class ConstantAsMetadata : public ValueAsMetadata {
friend class ValueAsMetadata;
ConstantAsMetadata(Constant *C)
: ValueAsMetadata(ConstantAsMetadataKind, C) {}
public:
static ConstantAsMetadata *get(Constant *C) {
return ValueAsMetadata::getConstant(C);
}
static ConstantAsMetadata *getIfExists(Constant *C) {
return ValueAsMetadata::getConstantIfExists(C);
}
Constant *getValue() const {
return cast<Constant>(ValueAsMetadata::getValue());
}
static bool classof(const Metadata *MD) {
return MD->getMetadataID() == ConstantAsMetadataKind;
}
};
class LocalAsMetadata : public ValueAsMetadata {
friend class ValueAsMetadata;
LocalAsMetadata(Value *Local)
: ValueAsMetadata(LocalAsMetadataKind, Local) {
assert(!isa<Constant>(Local) && "Expected local value");
}
public:
static LocalAsMetadata *get(Value *Local) {
return ValueAsMetadata::getLocal(Local);
}
static LocalAsMetadata *getIfExists(Value *Local) {
return ValueAsMetadata::getLocalIfExists(Local);
}
static bool classof(const Metadata *MD) {
return MD->getMetadataID() == LocalAsMetadataKind;
}
};
/// \brief Transitional API for extracting constants from Metadata.
///
/// This namespace contains transitional functions for metadata that points to
/// \a Constants.
///
/// In prehistory -- when metadata was a subclass of \a Value -- \a MDNode
/// operands could refer to any \a Value. There's was a lot of code like this:
///
/// \code
/// MDNode *N = ...;
/// auto *CI = dyn_cast<ConstantInt>(N->getOperand(2));
/// \endcode
///
/// Now that \a Value and \a Metadata are in separate hierarchies, maintaining
/// the semantics for \a isa(), \a cast(), \a dyn_cast() (etc.) requires three
/// steps: cast in the \a Metadata hierarchy, extraction of the \a Value, and
/// cast in the \a Value hierarchy. Besides creating boiler-plate, this
/// requires subtle control flow changes.
///
/// The end-goal is to create a new type of metadata, called (e.g.) \a MDInt,
/// so that metadata can refer to numbers without traversing a bridge to the \a
/// Value hierarchy. In this final state, the code above would look like this:
///
/// \code
/// MDNode *N = ...;
/// auto *MI = dyn_cast<MDInt>(N->getOperand(2));
/// \endcode
///
/// The API in this namespace supports the transition. \a MDInt doesn't exist
/// yet, and even once it does, changing each metadata schema to use it is its
/// own mini-project. In the meantime this API prevents us from introducing
/// complex and bug-prone control flow that will disappear in the end. In
/// particular, the above code looks like this:
///
/// \code
/// MDNode *N = ...;
/// auto *CI = mdconst::dyn_extract<ConstantInt>(N->getOperand(2));
/// \endcode
///
/// The full set of provided functions includes:
///
/// mdconst::hasa <=> isa
/// mdconst::extract <=> cast
/// mdconst::extract_or_null <=> cast_or_null
/// mdconst::dyn_extract <=> dyn_cast
/// mdconst::dyn_extract_or_null <=> dyn_cast_or_null
///
/// The target of the cast must be a subclass of \a Constant.
namespace mdconst {
namespace detail {
template <class T> T &make();
template <class T, class Result> struct HasDereference {
using Yes = char[1];
using No = char[2];
template <size_t N> struct SFINAE {};
template <class U, class V>
static Yes &hasDereference(SFINAE<sizeof(static_cast<V>(*make<U>()))> * = 0);
template <class U, class V> static No &hasDereference(...);
static const bool value =
sizeof(hasDereference<T, Result>(nullptr)) == sizeof(Yes);
};
template <class V, class M> struct IsValidPointer {
static const bool value = std::is_base_of<Constant, V>::value &&
HasDereference<M, const Metadata &>::value;
};
template <class V, class M> struct IsValidReference {
static const bool value = std::is_base_of<Constant, V>::value &&
std::is_convertible<M, const Metadata &>::value;
};
} // end namespace detail
/// \brief Check whether Metadata has a Value.
///
/// As an analogue to \a isa(), check whether \c MD has an \a Value inside of
/// type \c X.
template <class X, class Y>
inline typename std::enable_if<detail::IsValidPointer<X, Y>::value, bool>::type
hasa(Y &&MD) {
assert(MD && "Null pointer sent into hasa");
if (auto *V = dyn_cast<ConstantAsMetadata>(MD))
return isa<X>(V->getValue());
return false;
}
template <class X, class Y>
inline
typename std::enable_if<detail::IsValidReference<X, Y &>::value, bool>::type
hasa(Y &MD) {
return hasa(&MD);
}
/// \brief Extract a Value from Metadata.
///
/// As an analogue to \a cast(), extract the \a Value subclass \c X from \c MD.
template <class X, class Y>
inline typename std::enable_if<detail::IsValidPointer<X, Y>::value, X *>::type
extract(Y &&MD) {
return cast<X>(cast<ConstantAsMetadata>(MD)->getValue());
}
template <class X, class Y>
inline
typename std::enable_if<detail::IsValidReference<X, Y &>::value, X *>::type
extract(Y &MD) {
return extract(&MD);
}
/// \brief Extract a Value from Metadata, allowing null.
///
/// As an analogue to \a cast_or_null(), extract the \a Value subclass \c X
/// from \c MD, allowing \c MD to be null.
template <class X, class Y>
inline typename std::enable_if<detail::IsValidPointer<X, Y>::value, X *>::type
extract_or_null(Y &&MD) {
if (auto *V = cast_or_null<ConstantAsMetadata>(MD))
return cast<X>(V->getValue());
return nullptr;
}
/// \brief Extract a Value from Metadata, if any.
///
/// As an analogue to \a dyn_cast_or_null(), extract the \a Value subclass \c X
/// from \c MD, return null if \c MD doesn't contain a \a Value or if the \a
/// Value it does contain is of the wrong subclass.
template <class X, class Y>
inline typename std::enable_if<detail::IsValidPointer<X, Y>::value, X *>::type
dyn_extract(Y &&MD) {
if (auto *V = dyn_cast<ConstantAsMetadata>(MD))
return dyn_cast<X>(V->getValue());
return nullptr;
}
/// \brief Extract a Value from Metadata, if any, allowing null.
///
/// As an analogue to \a dyn_cast_or_null(), extract the \a Value subclass \c X
/// from \c MD, return null if \c MD doesn't contain a \a Value or if the \a
/// Value it does contain is of the wrong subclass, allowing \c MD to be null.
template <class X, class Y>
inline typename std::enable_if<detail::IsValidPointer<X, Y>::value, X *>::type
dyn_extract_or_null(Y &&MD) {
if (auto *V = dyn_cast_or_null<ConstantAsMetadata>(MD))
return dyn_cast<X>(V->getValue());
return nullptr;
}
} // end namespace mdconst
//===----------------------------------------------------------------------===//
/// \brief A single uniqued string.
///
/// These are used to efficiently contain a byte sequence for metadata.
/// MDString is always unnamed.
class MDString : public Metadata {
friend class StringMapEntry<MDString>;
StringMapEntry<MDString> *Entry = nullptr;
MDString() : Metadata(MDStringKind, Uniqued) {}
public:
MDString(const MDString &) = delete;
MDString &operator=(MDString &&) = delete;
MDString &operator=(const MDString &) = delete;
static MDString *get(LLVMContext &Context, StringRef Str);
static MDString *get(LLVMContext &Context, const char *Str) {
return get(Context, Str ? StringRef(Str) : StringRef());
}
StringRef getString() const;
unsigned getLength() const { return (unsigned)getString().size(); }
using iterator = StringRef::iterator;
/// \brief Pointer to the first byte of the string.
iterator begin() const { return getString().begin(); }
/// \brief Pointer to one byte past the end of the string.
iterator end() const { return getString().end(); }
const unsigned char *bytes_begin() const { return getString().bytes_begin(); }
const unsigned char *bytes_end() const { return getString().bytes_end(); }
/// \brief Methods for support type inquiry through isa, cast, and dyn_cast.
static bool classof(const Metadata *MD) {
return MD->getMetadataID() == MDStringKind;
}
};
/// \brief A collection of metadata nodes that might be associated with a
/// memory access used by the alias-analysis infrastructure.
struct AAMDNodes {
explicit AAMDNodes(MDNode *T = nullptr, MDNode *S = nullptr,
MDNode *N = nullptr)
: TBAA(T), Scope(S), NoAlias(N) {}
bool operator==(const AAMDNodes &A) const {
return TBAA == A.TBAA && Scope == A.Scope && NoAlias == A.NoAlias;
}
bool operator!=(const AAMDNodes &A) const { return !(*this == A); }
explicit operator bool() const { return TBAA || Scope || NoAlias; }
/// \brief The tag for type-based alias analysis.
MDNode *TBAA;
/// \brief The tag for alias scope specification (used with noalias).
MDNode *Scope;
/// \brief The tag specifying the noalias scope.
MDNode *NoAlias;
/// \brief Given two sets of AAMDNodes that apply to the same pointer,
/// give the best AAMDNodes that are compatible with both (i.e. a set of
/// nodes whose allowable aliasing conclusions are a subset of those
/// allowable by both of the inputs). However, for efficiency
/// reasons, do not create any new MDNodes.
AAMDNodes intersect(const AAMDNodes &Other) {
AAMDNodes Result;
Result.TBAA = Other.TBAA == TBAA ? TBAA : nullptr;
Result.Scope = Other.Scope == Scope ? Scope : nullptr;
Result.NoAlias = Other.NoAlias == NoAlias ? NoAlias : nullptr;
return Result;
}
};
// Specialize DenseMapInfo for AAMDNodes.
template<>
struct DenseMapInfo<AAMDNodes> {
static inline AAMDNodes getEmptyKey() {
return AAMDNodes(DenseMapInfo<MDNode *>::getEmptyKey(),
nullptr, nullptr);
}
static inline AAMDNodes getTombstoneKey() {
return AAMDNodes(DenseMapInfo<MDNode *>::getTombstoneKey(),
nullptr, nullptr);
}
static unsigned getHashValue(const AAMDNodes &Val) {
return DenseMapInfo<MDNode *>::getHashValue(Val.TBAA) ^
DenseMapInfo<MDNode *>::getHashValue(Val.Scope) ^
DenseMapInfo<MDNode *>::getHashValue(Val.NoAlias);
}
static bool isEqual(const AAMDNodes &LHS, const AAMDNodes &RHS) {
return LHS == RHS;
}
};
/// \brief Tracking metadata reference owned by Metadata.
///
/// Similar to \a TrackingMDRef, but it's expected to be owned by an instance
/// of \a Metadata, which has the option of registering itself for callbacks to
/// re-unique itself.
///
/// In particular, this is used by \a MDNode.
class MDOperand {
Metadata *MD = nullptr;
public:
MDOperand() = default;
MDOperand(MDOperand &&) = delete;
MDOperand(const MDOperand &) = delete;
MDOperand &operator=(MDOperand &&) = delete;
MDOperand &operator=(const MDOperand &) = delete;
~MDOperand() { untrack(); }
Metadata *get() const { return MD; }
operator Metadata *() const { return get(); }
Metadata *operator->() const { return get(); }
Metadata &operator*() const { return *get(); }
void reset() {
untrack();
MD = nullptr;
}
void reset(Metadata *MD, Metadata *Owner) {
untrack();
this->MD = MD;
track(Owner);
}
private:
void track(Metadata *Owner) {
if (MD) {
if (Owner)
MetadataTracking::track(this, *MD, *Owner);
else
MetadataTracking::track(MD);
}
}
void untrack() {
assert(static_cast<void *>(this) == &MD && "Expected same address");
if (MD)
MetadataTracking::untrack(MD);
}
};
template <> struct simplify_type<MDOperand> {
using SimpleType = Metadata *;
static SimpleType getSimplifiedValue(MDOperand &MD) { return MD.get(); }
};
template <> struct simplify_type<const MDOperand> {
using SimpleType = Metadata *;
static SimpleType getSimplifiedValue(const MDOperand &MD) { return MD.get(); }
};
/// \brief Pointer to the context, with optional RAUW support.
///
/// Either a raw (non-null) pointer to the \a LLVMContext, or an owned pointer
/// to \a ReplaceableMetadataImpl (which has a reference to \a LLVMContext).
class ContextAndReplaceableUses {
PointerUnion<LLVMContext *, ReplaceableMetadataImpl *> Ptr;
public:
ContextAndReplaceableUses(LLVMContext &Context) : Ptr(&Context) {}
ContextAndReplaceableUses(
std::unique_ptr<ReplaceableMetadataImpl> ReplaceableUses)
: Ptr(ReplaceableUses.release()) {
assert(getReplaceableUses() && "Expected non-null replaceable uses");
}
ContextAndReplaceableUses() = delete;
ContextAndReplaceableUses(ContextAndReplaceableUses &&) = delete;
ContextAndReplaceableUses(const ContextAndReplaceableUses &) = delete;
ContextAndReplaceableUses &operator=(ContextAndReplaceableUses &&) = delete;
ContextAndReplaceableUses &
operator=(const ContextAndReplaceableUses &) = delete;
~ContextAndReplaceableUses() { delete getReplaceableUses(); }
operator LLVMContext &() { return getContext(); }
/// \brief Whether this contains RAUW support.
bool hasReplaceableUses() const {
return Ptr.is<ReplaceableMetadataImpl *>();
}
LLVMContext &getContext() const {
if (hasReplaceableUses())
return getReplaceableUses()->getContext();
return *Ptr.get<LLVMContext *>();
}
ReplaceableMetadataImpl *getReplaceableUses() const {
if (hasReplaceableUses())
return Ptr.get<ReplaceableMetadataImpl *>();
return nullptr;
}
/// Ensure that this has RAUW support, and then return it.
ReplaceableMetadataImpl *getOrCreateReplaceableUses() {
if (!hasReplaceableUses())
makeReplaceable(llvm::make_unique<ReplaceableMetadataImpl>(getContext()));
return getReplaceableUses();
}
/// \brief Assign RAUW support to this.
///
/// Make this replaceable, taking ownership of \c ReplaceableUses (which must
/// not be null).
void
makeReplaceable(std::unique_ptr<ReplaceableMetadataImpl> ReplaceableUses) {
assert(ReplaceableUses && "Expected non-null replaceable uses");
assert(&ReplaceableUses->getContext() == &getContext() &&
"Expected same context");
delete getReplaceableUses();
Ptr = ReplaceableUses.release();
}
/// \brief Drop RAUW support.
///
/// Cede ownership of RAUW support, returning it.
std::unique_ptr<ReplaceableMetadataImpl> takeReplaceableUses() {
assert(hasReplaceableUses() && "Expected to own replaceable uses");
std::unique_ptr<ReplaceableMetadataImpl> ReplaceableUses(
getReplaceableUses());
Ptr = &ReplaceableUses->getContext();
return ReplaceableUses;
}
};
struct TempMDNodeDeleter {
inline void operator()(MDNode *Node) const;
};
#define HANDLE_MDNODE_LEAF(CLASS) \
using Temp##CLASS = std::unique_ptr<CLASS, TempMDNodeDeleter>;
#define HANDLE_MDNODE_BRANCH(CLASS) HANDLE_MDNODE_LEAF(CLASS)
#include "llvm/IR/Metadata.def"
/// \brief Metadata node.
///
/// Metadata nodes can be uniqued, like constants, or distinct. Temporary
/// metadata nodes (with full support for RAUW) can be used to delay uniquing
/// until forward references are known. The basic metadata node is an \a
/// MDTuple.
///
/// There is limited support for RAUW at construction time. At construction
/// time, if any operand is a temporary node (or an unresolved uniqued node,
/// which indicates a transitive temporary operand), the node itself will be
/// unresolved. As soon as all operands become resolved, it will drop RAUW
/// support permanently.
///
/// If an unresolved node is part of a cycle, \a resolveCycles() needs
/// to be called on some member of the cycle once all temporary nodes have been
/// replaced.
class MDNode : public Metadata {
friend class ReplaceableMetadataImpl;
friend class LLVMContextImpl;
unsigned NumOperands;
unsigned NumUnresolved;
ContextAndReplaceableUses Context;
protected:
MDNode(LLVMContext &Context, unsigned ID, StorageType Storage,
ArrayRef<Metadata *> Ops1, ArrayRef<Metadata *> Ops2 = None);
~MDNode() = default;
void *operator new(size_t Size, unsigned NumOps);
void operator delete(void *Mem);
/// \brief Required by std, but never called.
void operator delete(void *, unsigned) {
llvm_unreachable("Constructor throws?");
}
/// \brief Required by std, but never called.
void operator delete(void *, unsigned, bool) {
llvm_unreachable("Constructor throws?");
}
void dropAllReferences();
MDOperand *mutable_begin() { return mutable_end() - NumOperands; }
MDOperand *mutable_end() { return reinterpret_cast<MDOperand *>(this); }
using mutable_op_range = iterator_range<MDOperand *>;
mutable_op_range mutable_operands() {
return mutable_op_range(mutable_begin(), mutable_end());
}
public:
MDNode(const MDNode &) = delete;
void operator=(const MDNode &) = delete;
void *operator new(size_t) = delete;
static inline MDTuple *get(LLVMContext &Context, ArrayRef<Metadata *> MDs);
static inline MDTuple *getIfExists(LLVMContext &Context,
ArrayRef<Metadata *> MDs);
static inline MDTuple *getDistinct(LLVMContext &Context,
ArrayRef<Metadata *> MDs);
static inline TempMDTuple getTemporary(LLVMContext &Context,
ArrayRef<Metadata *> MDs);
/// \brief Create a (temporary) clone of this.
TempMDNode clone() const;
/// \brief Deallocate a node created by getTemporary.
///
/// Calls \c replaceAllUsesWith(nullptr) before deleting, so any remaining
/// references will be reset.
static void deleteTemporary(MDNode *N);
LLVMContext &getContext() const { return Context.getContext(); }
/// \brief Replace a specific operand.
void replaceOperandWith(unsigned I, Metadata *New);
/// \brief Check if node is fully resolved.
///
/// If \a isTemporary(), this always returns \c false; if \a isDistinct(),
/// this always returns \c true.
///
/// If \a isUniqued(), returns \c true if this has already dropped RAUW
/// support (because all operands are resolved).
///
/// As forward declarations are resolved, their containers should get
/// resolved automatically. However, if this (or one of its operands) is
/// involved in a cycle, \a resolveCycles() needs to be called explicitly.
bool isResolved() const { return !isTemporary() && !NumUnresolved; }
bool isUniqued() const { return Storage == Uniqued; }
bool isDistinct() const { return Storage == Distinct; }
bool isTemporary() const { return Storage == Temporary; }
/// \brief RAUW a temporary.
///
/// \pre \a isTemporary() must be \c true.
void replaceAllUsesWith(Metadata *MD) {
assert(isTemporary() && "Expected temporary node");
if (Context.hasReplaceableUses())
Context.getReplaceableUses()->replaceAllUsesWith(MD);
}
/// \brief Resolve cycles.
///
/// Once all forward declarations have been resolved, force cycles to be
/// resolved.
///
/// \pre No operands (or operands' operands, etc.) have \a isTemporary().
void resolveCycles();
/// \brief Replace a temporary node with a permanent one.
///
/// Try to create a uniqued version of \c N -- in place, if possible -- and
/// return it. If \c N cannot be uniqued, return a distinct node instead.
template <class T>
static typename std::enable_if<std::is_base_of<MDNode, T>::value, T *>::type
replaceWithPermanent(std::unique_ptr<T, TempMDNodeDeleter> N) {
return cast<T>(N.release()->replaceWithPermanentImpl());
}
/// \brief Replace a temporary node with a uniqued one.
///
/// Create a uniqued version of \c N -- in place, if possible -- and return
/// it. Takes ownership of the temporary node.
///
/// \pre N does not self-reference.
template <class T>
static typename std::enable_if<std::is_base_of<MDNode, T>::value, T *>::type
replaceWithUniqued(std::unique_ptr<T, TempMDNodeDeleter> N) {
return cast<T>(N.release()->replaceWithUniquedImpl());
}
/// \brief Replace a temporary node with a distinct one.
///
/// Create a distinct version of \c N -- in place, if possible -- and return
/// it. Takes ownership of the temporary node.
template <class T>
static typename std::enable_if<std::is_base_of<MDNode, T>::value, T *>::type
replaceWithDistinct(std::unique_ptr<T, TempMDNodeDeleter> N) {
return cast<T>(N.release()->replaceWithDistinctImpl());
}
private:
MDNode *replaceWithPermanentImpl();
MDNode *replaceWithUniquedImpl();
MDNode *replaceWithDistinctImpl();
protected:
/// \brief Set an operand.
///
/// Sets the operand directly, without worrying about uniquing.
void setOperand(unsigned I, Metadata *New);
void storeDistinctInContext();
template <class T, class StoreT>
static T *storeImpl(T *N, StorageType Storage, StoreT &Store);
template <class T> static T *storeImpl(T *N, StorageType Storage);
private:
void handleChangedOperand(void *Ref, Metadata *New);
/// Resolve a unique, unresolved node.
void resolve();
/// Drop RAUW support, if any.
void dropReplaceableUses();
void resolveAfterOperandChange(Metadata *Old, Metadata *New);
void decrementUnresolvedOperandCount();
void countUnresolvedOperands();
/// \brief Mutate this to be "uniqued".
///
/// Mutate this so that \a isUniqued().
/// \pre \a isTemporary().
/// \pre already added to uniquing set.
void makeUniqued();
/// \brief Mutate this to be "distinct".
///
/// Mutate this so that \a isDistinct().
/// \pre \a isTemporary().
void makeDistinct();
void deleteAsSubclass();
MDNode *uniquify();
void eraseFromStore();
template <class NodeTy> struct HasCachedHash;
template <class NodeTy>
static void dispatchRecalculateHash(NodeTy *N, std::true_type) {
N->recalculateHash();
}
template <class NodeTy>
static void dispatchRecalculateHash(NodeTy *, std::false_type) {}
template <class NodeTy>
static void dispatchResetHash(NodeTy *N, std::true_type) {
N->setHash(0);
}
template <class NodeTy>
static void dispatchResetHash(NodeTy *, std::false_type) {}
public:
using op_iterator = const MDOperand *;
using op_range = iterator_range<op_iterator>;
op_iterator op_begin() const {
return const_cast<MDNode *>(this)->mutable_begin();
}
op_iterator op_end() const {
return const_cast<MDNode *>(this)->mutable_end();
}
op_range operands() const { return op_range(op_begin(), op_end()); }
const MDOperand &getOperand(unsigned I) const {
assert(I < NumOperands && "Out of range");
return op_begin()[I];
}
/// \brief Return number of MDNode operands.
unsigned getNumOperands() const { return NumOperands; }
/// \brief Methods for support type inquiry through isa, cast, and dyn_cast:
static bool classof(const Metadata *MD) {
switch (MD->getMetadataID()) {
default:
return false;
#define HANDLE_MDNODE_LEAF(CLASS) \
case CLASS##Kind: \
return true;
#include "llvm/IR/Metadata.def"
}
}
/// \brief Check whether MDNode is a vtable access.
bool isTBAAVtableAccess() const;
/// \brief Methods for metadata merging.
static MDNode *concatenate(MDNode *A, MDNode *B);
static MDNode *intersect(MDNode *A, MDNode *B);
static MDNode *getMostGenericTBAA(MDNode *A, MDNode *B);
static MDNode *getMostGenericFPMath(MDNode *A, MDNode *B);
static MDNode *getMostGenericRange(MDNode *A, MDNode *B);
static MDNode *getMostGenericAliasScope(MDNode *A, MDNode *B);
static MDNode *getMostGenericAlignmentOrDereferenceable(MDNode *A, MDNode *B);
};
/// \brief Tuple of metadata.
///
/// This is the simple \a MDNode arbitrary tuple. Nodes are uniqued by
/// default based on their operands.
class MDTuple : public MDNode {
friend class LLVMContextImpl;
friend class MDNode;
MDTuple(LLVMContext &C, StorageType Storage, unsigned Hash,
ArrayRef<Metadata *> Vals)
: MDNode(C, MDTupleKind, Storage, Vals) {
setHash(Hash);
}
~MDTuple() { dropAllReferences(); }
void setHash(unsigned Hash) { SubclassData32 = Hash; }
void recalculateHash();
static MDTuple *getImpl(LLVMContext &Context, ArrayRef<Metadata *> MDs,
StorageType Storage, bool ShouldCreate = true);
TempMDTuple cloneImpl() const {
return getTemporary(getContext(),
SmallVector<Metadata *, 4>(op_begin(), op_end()));
}
public:
/// \brief Get the hash, if any.
unsigned getHash() const { return SubclassData32; }
static MDTuple *get(LLVMContext &Context, ArrayRef<Metadata *> MDs) {
return getImpl(Context, MDs, Uniqued);
}
static MDTuple *getIfExists(LLVMContext &Context, ArrayRef<Metadata *> MDs) {
return getImpl(Context, MDs, Uniqued, /* ShouldCreate */ false);
}
/// \brief Return a distinct node.
///
/// Return a distinct node -- i.e., a node that is not uniqued.
static MDTuple *getDistinct(LLVMContext &Context, ArrayRef<Metadata *> MDs) {
return getImpl(Context, MDs, Distinct);
}
/// \brief Return a temporary node.
///
/// For use in constructing cyclic MDNode structures. A temporary MDNode is
/// not uniqued, may be RAUW'd, and must be manually deleted with
/// deleteTemporary.
static TempMDTuple getTemporary(LLVMContext &Context,
ArrayRef<Metadata *> MDs) {
return TempMDTuple(getImpl(Context, MDs, Temporary));
}
/// \brief Return a (temporary) clone of this.
TempMDTuple clone() const { return cloneImpl(); }
static bool classof(const Metadata *MD) {
return MD->getMetadataID() == MDTupleKind;
}
};
MDTuple *MDNode::get(LLVMContext &Context, ArrayRef<Metadata *> MDs) {
return MDTuple::get(Context, MDs);
}
MDTuple *MDNode::getIfExists(LLVMContext &Context, ArrayRef<Metadata *> MDs) {
return MDTuple::getIfExists(Context, MDs);
}
MDTuple *MDNode::getDistinct(LLVMContext &Context, ArrayRef<Metadata *> MDs) {
return MDTuple::getDistinct(Context, MDs);
}
TempMDTuple MDNode::getTemporary(LLVMContext &Context,
ArrayRef<Metadata *> MDs) {
return MDTuple::getTemporary(Context, MDs);
}
void TempMDNodeDeleter::operator()(MDNode *Node) const {
MDNode::deleteTemporary(Node);
}
/// \brief Typed iterator through MDNode operands.
///
/// An iterator that transforms an \a MDNode::iterator into an iterator over a
/// particular Metadata subclass.
template <class T>
class TypedMDOperandIterator
: public std::iterator<std::input_iterator_tag, T *, std::ptrdiff_t, void,
T *> {
MDNode::op_iterator I = nullptr;
public:
TypedMDOperandIterator() = default;
explicit TypedMDOperandIterator(MDNode::op_iterator I) : I(I) {}
T *operator*() const { return cast_or_null<T>(*I); }
TypedMDOperandIterator &operator++() {
++I;
return *this;
}
TypedMDOperandIterator operator++(int) {
TypedMDOperandIterator Temp(*this);
++I;
return Temp;
}
bool operator==(const TypedMDOperandIterator &X) const { return I == X.I; }
bool operator!=(const TypedMDOperandIterator &X) const { return I != X.I; }
};
/// \brief Typed, array-like tuple of metadata.
///
/// This is a wrapper for \a MDTuple that makes it act like an array holding a
/// particular type of metadata.
template <class T> class MDTupleTypedArrayWrapper {
const MDTuple *N = nullptr;
public:
MDTupleTypedArrayWrapper() = default;
MDTupleTypedArrayWrapper(const MDTuple *N) : N(N) {}
template <class U>
MDTupleTypedArrayWrapper(
const MDTupleTypedArrayWrapper<U> &Other,
typename std::enable_if<std::is_convertible<U *, T *>::value>::type * =
nullptr)
: N(Other.get()) {}
template <class U>
explicit MDTupleTypedArrayWrapper(
const MDTupleTypedArrayWrapper<U> &Other,
typename std::enable_if<!std::is_convertible<U *, T *>::value>::type * =
nullptr)
: N(Other.get()) {}
explicit operator bool() const { return get(); }
explicit operator MDTuple *() const { return get(); }
MDTuple *get() const { return const_cast<MDTuple *>(N); }
MDTuple *operator->() const { return get(); }
MDTuple &operator*() const { return *get(); }
// FIXME: Fix callers and remove condition on N.
unsigned size() const { return N ? N->getNumOperands() : 0u; }
bool empty() const { return N ? N->getNumOperands() == 0 : true; }
T *operator[](unsigned I) const { return cast_or_null<T>(N->getOperand(I)); }
// FIXME: Fix callers and remove condition on N.
using iterator = TypedMDOperandIterator<T>;
iterator begin() const { return N ? iterator(N->op_begin()) : iterator(); }
iterator end() const { return N ? iterator(N->op_end()) : iterator(); }
};
#define HANDLE_METADATA(CLASS) \
using CLASS##Array = MDTupleTypedArrayWrapper<CLASS>;
#include "llvm/IR/Metadata.def"
/// Placeholder metadata for operands of distinct MDNodes.
///
/// This is a lightweight placeholder for an operand of a distinct node. It's
/// purpose is to help track forward references when creating a distinct node.
/// This allows distinct nodes involved in a cycle to be constructed before
/// their operands without requiring a heavyweight temporary node with
/// full-blown RAUW support.
///
/// Each placeholder supports only a single MDNode user. Clients should pass
/// an ID, retrieved via \a getID(), to indicate the "real" operand that this
/// should be replaced with.
///
/// While it would be possible to implement move operators, they would be
/// fairly expensive. Leave them unimplemented to discourage their use
/// (clients can use std::deque, std::list, BumpPtrAllocator, etc.).
class DistinctMDOperandPlaceholder : public Metadata {
friend class MetadataTracking;
Metadata **Use = nullptr;
public:
explicit DistinctMDOperandPlaceholder(unsigned ID)
: Metadata(DistinctMDOperandPlaceholderKind, Distinct) {
SubclassData32 = ID;
}
DistinctMDOperandPlaceholder() = delete;
DistinctMDOperandPlaceholder(DistinctMDOperandPlaceholder &&) = delete;
DistinctMDOperandPlaceholder(const DistinctMDOperandPlaceholder &) = delete;
~DistinctMDOperandPlaceholder() {
if (Use)
*Use = nullptr;
}
unsigned getID() const { return SubclassData32; }
/// Replace the use of this with MD.
void replaceUseWith(Metadata *MD) {
if (!Use)
return;
*Use = MD;
if (*Use)
MetadataTracking::track(*Use);
Metadata *T = cast<Metadata>(this);
MetadataTracking::untrack(T);
assert(!Use && "Use is still being tracked despite being untracked!");
}
};
//===----------------------------------------------------------------------===//
/// \brief A tuple of MDNodes.
///
/// Despite its name, a NamedMDNode isn't itself an MDNode. NamedMDNodes belong
/// to modules, have names, and contain lists of MDNodes.
///
/// TODO: Inherit from Metadata.
class NamedMDNode : public ilist_node<NamedMDNode> {
friend class LLVMContextImpl;
friend class Module;
std::string Name;
Module *Parent = nullptr;
void *Operands; // SmallVector<TrackingMDRef, 4>
void setParent(Module *M) { Parent = M; }
explicit NamedMDNode(const Twine &N);
template<class T1, class T2>
class op_iterator_impl :
public std::iterator<std::bidirectional_iterator_tag, T2> {
friend class NamedMDNode;
const NamedMDNode *Node = nullptr;
unsigned Idx = 0;
op_iterator_impl(const NamedMDNode *N, unsigned i) : Node(N), Idx(i) {}
public:
op_iterator_impl() = default;
bool operator==(const op_iterator_impl &o) const { return Idx == o.Idx; }
bool operator!=(const op_iterator_impl &o) const { return Idx != o.Idx; }
op_iterator_impl &operator++() {
++Idx;
return *this;
}
op_iterator_impl operator++(int) {
op_iterator_impl tmp(*this);
operator++();
return tmp;
}
op_iterator_impl &operator--() {
--Idx;
return *this;
}
op_iterator_impl operator--(int) {
op_iterator_impl tmp(*this);
operator--();
return tmp;
}
T1 operator*() const { return Node->getOperand(Idx); }
};
public:
NamedMDNode(const NamedMDNode &) = delete;
~NamedMDNode();
/// \brief Drop all references and remove the node from parent module.
void eraseFromParent();
/// Remove all uses and clear node vector.
void dropAllReferences() { clearOperands(); }
/// Drop all references to this node's operands.
void clearOperands();
/// \brief Get the module that holds this named metadata collection.
inline Module *getParent() { return Parent; }
inline const Module *getParent() const { return Parent; }
MDNode *getOperand(unsigned i) const;
unsigned getNumOperands() const;
void addOperand(MDNode *M);
void setOperand(unsigned I, MDNode *New);
StringRef getName() const;
void print(raw_ostream &ROS, bool IsForDebug = false) const;
void print(raw_ostream &ROS, ModuleSlotTracker &MST,
bool IsForDebug = false) const;
void dump() const;
// ---------------------------------------------------------------------------
// Operand Iterator interface...
//
using op_iterator = op_iterator_impl<MDNode *, MDNode>;
op_iterator op_begin() { return op_iterator(this, 0); }
op_iterator op_end() { return op_iterator(this, getNumOperands()); }
using const_op_iterator = op_iterator_impl<const MDNode *, MDNode>;
const_op_iterator op_begin() const { return const_op_iterator(this, 0); }
const_op_iterator op_end() const { return const_op_iterator(this, getNumOperands()); }
inline iterator_range<op_iterator> operands() {
return make_range(op_begin(), op_end());
}
inline iterator_range<const_op_iterator> operands() const {
return make_range(op_begin(), op_end());
}
};
} // end namespace llvm
#endif // LLVM_IR_METADATA_H