llvm-6502/include/llvm/IR/Metadata.h
Duncan P. N. Exon Smith 4bedb48751 Bitcode: Use unsigned char to record MDStrings
`MDString`s can have arbitrary characters in them.  Prevent an assertion
that fired in `BitcodeWriter` because of sign extension by copying the
characters into the record as `unsigned char`s.

Based on a patch by Keno Fischer; fixes PR21882.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@224077 91177308-0d34-0410-b5e6-96231b3b80d8
2014-12-11 23:34:30 +00:00

882 lines
28 KiB
C++

//===-- llvm/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/ilist_node.h"
#include "llvm/ADT/iterator_range.h"
#include "llvm/IR/Constant.h"
#include "llvm/IR/MetadataTracking.h"
#include "llvm/IR/Value.h"
#include "llvm/Support/ErrorHandling.h"
#include <type_traits>
namespace llvm {
class LLVMContext;
class Module;
template<typename ValueSubClass, typename ItemParentClass>
class SymbolTableListTraits;
enum LLVMConstants : uint32_t {
DEBUG_METADATA_VERSION = 2 // 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 Storage flag for non-uniqued, otherwise unowned, metadata.
bool IsDistinctInContext : 1;
bool InRAUW : 1;
// TODO: expose remaining bits to subclasses.
unsigned short SubclassData16;
unsigned SubclassData32;
public:
enum MetadataKind {
GenericMDNodeKind,
MDNodeFwdDeclKind,
ConstantAsMetadataKind,
LocalAsMetadataKind,
MDStringKind
};
protected:
Metadata(unsigned ID)
: SubclassID(ID), IsDistinctInContext(false), InRAUW(false),
SubclassData16(0), SubclassData32(0) {}
~Metadata() {}
/// \brief Store this in a big non-uniqued untyped bucket.
bool isStoredDistinctInContext() const { return IsDistinctInContext; }
/// \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.
void dump() const;
void print(raw_ostream &OS) const;
void printAsOperand(raw_ostream &OS, bool PrintType = true,
const Module *M = nullptr) const;
};
#define HANDLE_METADATA(CLASS) class CLASS;
#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);
~MetadataAsValue();
public:
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 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:
typedef MetadataTracking::OwnerTy OwnerTy;
private:
uint64_t NextIndex;
SmallDenseMap<void *, std::pair<OwnerTy, uint64_t>, 4> UseMap;
public:
ReplaceableMetadataImpl() : NextIndex(0) {}
~ReplaceableMetadataImpl() {
assert(UseMap.empty() && "Cannot destroy in-use replaceable metadata");
}
/// \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 GenericMDNode::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);
static ReplaceableMetadataImpl *get(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;
protected:
ValueAsMetadata(LLVMContext &Context, unsigned ID, Value *V)
: Metadata(ID), V(V) {
assert(V && "Expected valid value");
}
~ValueAsMetadata() {}
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(LLVMContext &Context, Constant *C)
: ValueAsMetadata(Context, 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(LLVMContext &Context, Value *Local)
: ValueAsMetadata(Context, 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 {
typedef char Yes[1];
typedef char No[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>;
MDString(const MDString &) LLVM_DELETED_FUNCTION;
MDString &operator=(MDString &&) LLVM_DELETED_FUNCTION;
MDString &operator=(const MDString &) LLVM_DELETED_FUNCTION;
StringMapEntry<MDString> *Entry;
MDString() : Metadata(MDStringKind), Entry(nullptr) {}
MDString(MDString &&) : Metadata(MDStringKind) {}
public:
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(); }
typedef StringRef::iterator 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); }
LLVM_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;
};
// Specialize DenseMapInfo for AAMDNodes.
template<>
struct DenseMapInfo<AAMDNodes> {
static inline AAMDNodes getEmptyKey() {
return AAMDNodes(DenseMapInfo<MDNode *>::getEmptyKey(), 0, 0);
}
static inline AAMDNodes getTombstoneKey() {
return AAMDNodes(DenseMapInfo<MDNode *>::getTombstoneKey(), 0, 0);
}
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 {
MDOperand(MDOperand &&) LLVM_DELETED_FUNCTION;
MDOperand(const MDOperand &) LLVM_DELETED_FUNCTION;
MDOperand &operator=(MDOperand &&) LLVM_DELETED_FUNCTION;
MDOperand &operator=(const MDOperand &) LLVM_DELETED_FUNCTION;
Metadata *MD;
public:
MDOperand() : MD(nullptr) {}
~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> {
typedef Metadata *SimpleType;
static SimpleType getSimplifiedValue(MDOperand &MD) { return MD.get(); }
};
template <> struct simplify_type<const MDOperand> {
typedef Metadata *SimpleType;
static SimpleType getSimplifiedValue(const MDOperand &MD) { return MD.get(); }
};
//===----------------------------------------------------------------------===//
/// \brief Tuple of metadata.
class MDNode : public Metadata {
MDNode(const MDNode &) LLVM_DELETED_FUNCTION;
void operator=(const MDNode &) LLVM_DELETED_FUNCTION;
void *operator new(size_t) LLVM_DELETED_FUNCTION;
LLVMContext &Context;
unsigned NumOperands;
protected:
unsigned MDNodeSubclassData;
void *operator new(size_t Size, unsigned NumOps);
/// \brief Required by std, but never called.
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?");
}
MDNode(LLVMContext &Context, unsigned ID, ArrayRef<Metadata *> MDs);
~MDNode() {}
void dropAllReferences();
void storeDistinctInContext();
static MDNode *getMDNode(LLVMContext &C, ArrayRef<Metadata *> MDs,
bool Insert = true);
MDOperand *mutable_begin() { return mutable_end() - NumOperands; }
MDOperand *mutable_end() { return reinterpret_cast<MDOperand *>(this); }
public:
static MDNode *get(LLVMContext &Context, ArrayRef<Metadata *> MDs) {
return getMDNode(Context, MDs, true);
}
static MDNode *getWhenValsUnresolved(LLVMContext &Context,
ArrayRef<Metadata *> MDs) {
// TODO: Remove this.
return get(Context, MDs);
}
static MDNode *getIfExists(LLVMContext &Context, ArrayRef<Metadata *> MDs) {
return getMDNode(Context, MDs, false);
}
/// \brief Return a temporary MDNode
///
/// 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 MDNodeFwdDecl *getTemporary(LLVMContext &Context,
ArrayRef<Metadata *> MDs);
/// \brief Deallocate a node created by getTemporary.
///
/// The node must not have any users.
static void deleteTemporary(MDNode *N);
LLVMContext &getContext() const { return Context; }
/// \brief Replace a specific operand.
void replaceOperandWith(unsigned I, Metadata *New);
/// \brief Check if node is fully resolved.
bool isResolved() const;
protected:
/// \brief Set an operand.
///
/// Sets the operand directly, without worrying about uniquing.
void setOperand(unsigned I, Metadata *New);
public:
typedef const MDOperand *op_iterator;
typedef iterator_range<op_iterator> op_range;
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) {
return MD->getMetadataID() == GenericMDNodeKind ||
MD->getMetadataID() == MDNodeFwdDeclKind;
}
/// \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 AAMDNodes getMostGenericAA(const AAMDNodes &A, const AAMDNodes &B);
static MDNode *getMostGenericFPMath(MDNode *A, MDNode *B);
static MDNode *getMostGenericRange(MDNode *A, MDNode *B);
};
/// \brief Generic metadata node.
///
/// Generic metadata nodes, with opt-out support for uniquing.
///
/// Although nodes are uniqued by default, \a GenericMDNode has no support for
/// RAUW. If an operand change (due to RAUW or otherwise) causes a uniquing
/// collision, the uniquing bit is dropped.
///
/// TODO: Make uniquing opt-out (status: mandatory, sometimes dropped).
/// TODO: Drop support for RAUW.
class GenericMDNode : public MDNode {
friend class Metadata;
friend class MDNode;
friend class LLVMContextImpl;
friend class ReplaceableMetadataImpl;
/// \brief Support RAUW as long as one of its arguments is replaceable.
///
/// If an operand is an \a MDNodeFwdDecl (or a replaceable \a GenericMDNode),
/// support RAUW to support uniquing as forward declarations are resolved.
/// As soon as operands have been resolved, drop support.
///
/// FIXME: Save memory by storing this in a pointer union with the
/// LLVMContext, and adding an LLVMContext reference to RMI.
std::unique_ptr<ReplaceableMetadataImpl> ReplaceableUses;
GenericMDNode(LLVMContext &C, ArrayRef<Metadata *> Vals);
~GenericMDNode();
void setHash(unsigned Hash) { MDNodeSubclassData = Hash; }
public:
/// \brief Get the hash, if any.
unsigned getHash() const { return MDNodeSubclassData; }
static bool classof(const Metadata *MD) {
return MD->getMetadataID() == GenericMDNodeKind;
}
/// \brief Check whether any operands are forward declarations.
///
/// Returns \c true as long as any operands (or their operands, etc.) are \a
/// MDNodeFwdDecl.
///
/// 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 !ReplaceableUses; }
/// \brief Resolve cycles.
///
/// Once all forward declarations have been resolved, force cycles to be
/// resolved.
///
/// \pre No operands (or operands' operands, etc.) are \a MDNodeFwdDecl.
void resolveCycles();
private:
void handleChangedOperand(void *Ref, Metadata *New);
bool hasUnresolvedOperands() const { return SubclassData32; }
void incrementUnresolvedOperands() { ++SubclassData32; }
void decrementUnresolvedOperands() { --SubclassData32; }
void resolve();
};
/// \brief Forward declaration of metadata.
///
/// Forward declaration of metadata, in the form of a metadata node. Unlike \a
/// GenericMDNode, this class has support for RAUW and is suitable for forward
/// references.
class MDNodeFwdDecl : public MDNode, ReplaceableMetadataImpl {
friend class Metadata;
friend class MDNode;
friend class ReplaceableMetadataImpl;
MDNodeFwdDecl(LLVMContext &C, ArrayRef<Metadata *> Vals)
: MDNode(C, MDNodeFwdDeclKind, Vals) {}
~MDNodeFwdDecl() { dropAllReferences(); }
public:
static bool classof(const Metadata *MD) {
return MD->getMetadataID() == MDNodeFwdDeclKind;
}
using ReplaceableMetadataImpl::replaceAllUsesWith;
};
//===----------------------------------------------------------------------===//
/// \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 SymbolTableListTraits<NamedMDNode, Module>;
friend struct ilist_traits<NamedMDNode>;
friend class LLVMContextImpl;
friend class Module;
NamedMDNode(const NamedMDNode &) LLVM_DELETED_FUNCTION;
std::string Name;
Module *Parent;
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> {
const NamedMDNode *Node;
unsigned Idx;
op_iterator_impl(const NamedMDNode *N, unsigned i) : Node(N), Idx(i) { }
friend class NamedMDNode;
public:
op_iterator_impl() : Node(nullptr), Idx(0) { }
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:
/// \brief Drop all references and remove the node from parent module.
void eraseFromParent();
/// \brief Remove all uses and clear node vector.
void dropAllReferences();
~NamedMDNode();
/// \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);
StringRef getName() const;
void print(raw_ostream &ROS) const;
void dump() const;
// ---------------------------------------------------------------------------
// Operand Iterator interface...
//
typedef op_iterator_impl<MDNode *, MDNode> op_iterator;
op_iterator op_begin() { return op_iterator(this, 0); }
op_iterator op_end() { return op_iterator(this, getNumOperands()); }
typedef op_iterator_impl<const MDNode *, MDNode> const_op_iterator;
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 iterator_range<op_iterator>(op_begin(), op_end());
}
inline iterator_range<const_op_iterator> operands() const {
return iterator_range<const_op_iterator>(op_begin(), op_end());
}
};
} // end llvm namespace
#endif