#include "llvm/ADT/ArrayRef.h"
#include "llvm/ADT/DenseMap.h"
-#include "llvm/ADT/FoldingSet.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;
/// \brief Root of the metadata hierarchy.
///
/// This is a root class for typeless data in the IR.
-///
-/// TODO: Detach from the Value hierarchy.
-class Metadata : public Value {
+class Metadata {
+ friend class ReplaceableMetadataImpl;
+
+ /// \brief RTTI.
+ const unsigned char SubclassID;
+
protected:
- Metadata(LLVMContext &Context, unsigned ID);
+ /// \brief Storage flag for non-uniqued, otherwise unowned, metadata.
+ bool IsDistinctInContext : 1;
+ // TODO: expose remaining bits to subclasses.
+
+ unsigned short SubclassData16;
+ unsigned SubclassData32;
+
+public:
+ enum MetadataKind {
+ MDTupleKind,
+ MDNodeFwdDeclKind,
+ ConstantAsMetadataKind,
+ LocalAsMetadataKind,
+ MDStringKind
+ };
+
+protected:
+ Metadata(unsigned ID)
+ : SubclassID(ID), IsDistinctInContext(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() == GenericMDNodeVal ||
- V->getValueID() == MDNodeFwdDeclVal ||
- V->getValueID() == MDStringVal;
+ 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 UniquableMDNode::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(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(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 {
+ 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.
///
class MDString : public Metadata {
friend class StringMapEntry<MDString>;
- virtual void anchor();
MDString(const MDString &) LLVM_DELETED_FUNCTION;
+ MDString &operator=(MDString &&) LLVM_DELETED_FUNCTION;
+ MDString &operator=(const MDString &) LLVM_DELETED_FUNCTION;
StringMapEntry<MDString> *Entry;
- explicit MDString(LLVMContext &Context)
- : Metadata(Context, Value::MDStringVal), Entry(nullptr) {}
-
- /// \brief Shadow Value::getName() to prevent its use.
- StringRef getName() const LLVM_DELETED_FUNCTION;
+ MDString() : Metadata(MDStringKind), Entry(nullptr) {}
+ MDString(MDString &&) : Metadata(MDStringKind) {}
public:
static MDString *get(LLVMContext &Context, StringRef Str);
/// \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 Value *V) {
- return V->getValueID() == MDStringVal;
+ static bool classof(const Metadata *MD) {
+ return MD->getMetadataID() == MDStringKind;
}
};
}
};
-class MDNodeOperand;
+/// \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;
- friend class MDNodeOperand;
- friend class LLVMContextImpl;
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.
llvm_unreachable("Constructor throws?");
}
- /// \brief Subclass data enums.
- enum {
- /// FunctionLocalBit - This bit is set if this MDNode is function local.
- /// This is true when it (potentially transitively) contains a reference to
- /// something in a function, like an argument, basicblock, or instruction.
- FunctionLocalBit = 1 << 0,
-
- /// NotUniquedBit - This is set on MDNodes that are not uniqued because they
- /// have a null operand.
- NotUniquedBit = 1 << 1
- };
-
- /// \brief FunctionLocal enums.
- enum FunctionLocalness {
- FL_Unknown = -1,
- FL_No = 0,
- FL_Yes = 1
- };
+ MDNode(LLVMContext &Context, unsigned ID, ArrayRef<Metadata *> MDs);
+ ~MDNode() {}
- /// \brief Replace each instance of the given operand with a new value.
- void replaceOperand(MDNodeOperand *Op, Value *NewVal);
+ void dropAllReferences();
- MDNode(LLVMContext &C, unsigned ID, ArrayRef<Value *> Vals,
- bool isFunctionLocal);
- ~MDNode() {}
+ MDOperand *mutable_begin() { return mutable_end() - NumOperands; }
+ MDOperand *mutable_end() { return reinterpret_cast<MDOperand *>(this); }
- static MDNode *getMDNode(LLVMContext &C, ArrayRef<Value*> Vals,
- FunctionLocalness FL, bool Insert = true);
public:
- static MDNode *get(LLVMContext &Context, ArrayRef<Value*> Vals);
- /// \brief Construct MDNode with an explicit function-localness.
- ///
- /// Don't analyze Vals; trust isFunctionLocal.
- static MDNode *getWhenValsUnresolved(LLVMContext &Context,
- ArrayRef<Value*> Vals,
- bool isFunctionLocal);
-
- static MDNode *getIfExists(LLVMContext &Context, ArrayRef<Value*> Vals);
+ static inline MDNode *get(LLVMContext &Context, ArrayRef<Metadata *> MDs);
+ static inline MDNode *getIfExists(LLVMContext &Context,
+ ArrayRef<Metadata *> MDs);
+ static inline MDNode *getDistinct(LLVMContext &Context,
+ ArrayRef<Metadata *> MDs);
/// \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 MDNode *getTemporary(LLVMContext &Context, ArrayRef<Value*> Vals);
+ 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);
- /// \brief Replace a specific operand.
- void replaceOperandWith(unsigned i, Value *NewVal);
+ LLVMContext &getContext() const { return Context; }
- /// \brief Return specified operand.
- Value *getOperand(unsigned i) const LLVM_READONLY;
+ /// \brief Replace a specific operand.
+ void replaceOperandWith(unsigned I, Metadata *New);
- /// \brief Return number of MDNode operands.
- unsigned getNumOperands() const { return NumOperands; }
+ /// \brief Check if node is fully resolved.
+ bool isResolved() const;
- /// \brief Return whether MDNode is local to a function.
- bool isFunctionLocal() const {
- return (getSubclassDataFromValue() & FunctionLocalBit) != 0;
+ /// \brief Check if node is distinct.
+ ///
+ /// Distinct nodes are not uniqued, and will not be returned by \a
+ /// MDNode::get().
+ bool isDistinct() const {
+ return isStoredDistinctInContext() || isa<MDNodeFwdDecl>(this);
}
- /// \brief Return the first function-local operand's function.
+protected:
+ /// \brief Set an operand.
///
- /// If this metadata is function-local and recursively has a function-local
- /// operand, return the first such operand's parent function. Otherwise,
- /// return null. getFunction() should not be used for performance- critical
- /// code because it recursively visits all the MDNode's operands.
- const Function *getFunction() const;
+ /// 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 Value *V) {
- return V->getValueID() == GenericMDNodeVal ||
- V->getValueID() == MDNodeFwdDeclVal;
+ static bool classof(const Metadata *MD) {
+ return MD->getMetadataID() == MDTupleKind ||
+ MD->getMetadataID() == MDNodeFwdDeclKind;
}
/// \brief Check whether MDNode is a vtable access.
static AAMDNodes getMostGenericAA(const AAMDNodes &A, const AAMDNodes &B);
static MDNode *getMostGenericFPMath(MDNode *A, MDNode *B);
static MDNode *getMostGenericRange(MDNode *A, MDNode *B);
+};
+
+/// \brief Uniquable metadata node.
+///
+/// A uniquable metadata node. This contains the basic functionality
+/// for implementing sub-types of \a MDNode that can be uniqued like
+/// constants.
+///
+/// There is limited support for RAUW at construction time. At
+/// construction time, if any operands are an instance of \a
+/// MDNodeFwdDecl (or another unresolved \a UniquableMDNode, which
+/// indicates an \a MDNodeFwdDecl in its path), 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 when each \a MDNodeFwdDecl
+/// has been removed.
+class UniquableMDNode : public MDNode {
+ friend class ReplaceableMetadataImpl;
+ friend class MDNode;
+ friend class LLVMContextImpl;
+
+ /// \brief Support RAUW as long as one of its arguments is replaceable.
+ ///
+ /// 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;
protected:
- bool isNotUniqued() const {
- return (getSubclassDataFromValue() & NotUniquedBit) != 0;
- }
- void setIsNotUniqued();
+ /// \brief Create a new node.
+ ///
+ /// If \c AllowRAUW, then if any operands are unresolved support RAUW. RAUW
+ /// will be dropped once all operands have been resolved (or if \a
+ /// resolveCycles() is called).
+ UniquableMDNode(LLVMContext &C, unsigned ID, ArrayRef<Metadata *> Vals,
+ bool AllowRAUW);
+ ~UniquableMDNode();
+
+ void storeDistinctInContext();
- // Shadow Value::setValueSubclassData with a private forwarding method so that
- // any future subclasses cannot accidentally use it.
- void setValueSubclassData(unsigned short D) {
- Value::setValueSubclassData(D);
+public:
+ static bool classof(const Metadata *MD) {
+ return MD->getMetadataID() == MDTupleKind;
}
+
+ /// \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);
+
+ void resolve();
+ void resolveAfterOperandChange(Metadata *Old, Metadata *New);
+ void decrementUnresolvedOperandCount();
};
-/// \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.
+/// \brief Tuple of metadata.
///
-/// TODO: Make uniquing opt-out (status: mandatory, sometimes dropped).
-/// TODO: Drop support for RAUW.
-class GenericMDNode : public MDNode {
- friend class MDNode;
+/// This is the simple \a MDNode arbitrary tuple. Nodes are uniqued by
+/// default based on their operands.
+class MDTuple : public UniquableMDNode {
friend class LLVMContextImpl;
+ friend class UniquableMDNode;
- unsigned Hash;
+ MDTuple(LLVMContext &C, ArrayRef<Metadata *> Vals, bool AllowRAUW)
+ : UniquableMDNode(C, MDTupleKind, Vals, AllowRAUW) {}
+ ~MDTuple();
- GenericMDNode(LLVMContext &C, ArrayRef<Value *> Vals, bool isFunctionLocal)
- : MDNode(C, GenericMDNodeVal, Vals, isFunctionLocal), Hash(0) {}
- ~GenericMDNode();
+ void setHash(unsigned Hash) { MDNodeSubclassData = Hash; }
+ void recalculateHash();
- void dropAllReferences();
+ static MDTuple *getImpl(LLVMContext &Context, ArrayRef<Metadata *> MDs,
+ bool ShouldCreate);
public:
/// \brief Get the hash, if any.
- unsigned getHash() const { return Hash; }
+ unsigned getHash() const { return MDNodeSubclassData; }
- static bool classof(const Value *V) {
- return V->getValueID() == GenericMDNodeVal;
+ static MDTuple *get(LLVMContext &Context, ArrayRef<Metadata *> MDs) {
+ return getImpl(Context, MDs, /* ShouldCreate */ true);
+ }
+ static MDTuple *getIfExists(LLVMContext &Context, ArrayRef<Metadata *> MDs) {
+ return getImpl(Context, MDs, /* 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);
+
+ static bool classof(const Metadata *MD) {
+ return MD->getMetadataID() == MDTupleKind;
}
};
+MDNode *MDNode::get(LLVMContext &Context, ArrayRef<Metadata *> MDs) {
+ return MDTuple::get(Context, MDs);
+}
+MDNode *MDNode::getIfExists(LLVMContext &Context, ArrayRef<Metadata *> MDs) {
+ return MDTuple::getIfExists(Context, MDs);
+}
+MDNode *MDNode::getDistinct(LLVMContext &Context, ArrayRef<Metadata *> MDs) {
+ return MDTuple::getDistinct(Context, MDs);
+}
+
/// \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 {
- friend class MDNode;
+/// Forward declaration of metadata, in the form of a basic tuple. Unlike \a
+/// MDTuple, this class has full support for RAUW, is not owned, is not
+/// uniqued, and is suitable for forward references.
+class MDNodeFwdDecl : public MDNode, ReplaceableMetadataImpl {
+ friend class Metadata;
+ friend class ReplaceableMetadataImpl;
- MDNodeFwdDecl(LLVMContext &C, ArrayRef<Value *> Vals, bool isFunctionLocal)
- : MDNode(C, MDNodeFwdDeclVal, Vals, isFunctionLocal) {}
- ~MDNodeFwdDecl() {}
+ MDNodeFwdDecl(LLVMContext &C, ArrayRef<Metadata *> Vals)
+ : MDNode(C, MDNodeFwdDeclKind, Vals) {}
public:
- static bool classof(const Value *V) {
- return V->getValueID() == MDNodeFwdDeclVal;
+ ~MDNodeFwdDecl() { dropAllReferences(); }
+ using MDNode::operator delete;
+
+ static MDNodeFwdDecl *get(LLVMContext &Context, ArrayRef<Metadata *> MDs) {
+ return new (MDs.size()) MDNodeFwdDecl(Context, MDs);
}
+
+ static bool classof(const Metadata *MD) {
+ return MD->getMetadataID() == MDNodeFwdDeclKind;
+ }
+
+ using ReplaceableMetadataImpl::replaceAllUsesWith;
};
//===----------------------------------------------------------------------===//
std::string Name;
Module *Parent;
- void *Operands; // SmallVector<TrackingVH<MDNode>, 4>
+ void *Operands; // SmallVector<TrackingMDRef, 4>
void setParent(Module *M) { Parent = M; }
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) const;
void dump() const;
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