+ 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 Storage : 2;
+ // TODO: expose remaining bits to subclasses.
+
+ unsigned short SubclassData16;
+ unsigned SubclassData32;
+
+public:
+ enum MetadataKind {
+ MDTupleKind,
+ DILocationKind,
+ GenericDINodeKind,
+ DISubrangeKind,
+ DIEnumeratorKind,
+ DIBasicTypeKind,
+ DIDerivedTypeKind,
+ DICompositeTypeKind,
+ DISubroutineTypeKind,
+ DIFileKind,
+ DICompileUnitKind,
+ DISubprogramKind,
+ DILexicalBlockKind,
+ DILexicalBlockFileKind,
+ DINamespaceKind,
+ DIModuleKind,
+ DITemplateTypeParameterKind,
+ DITemplateValueParameterKind,
+ DIGlobalVariableKind,
+ DILocalVariableKind,
+ DIExpressionKind,
+ DIObjCPropertyKind,
+ DIImportedEntityKind,
+ ConstantAsMetadataKind,
+ LocalAsMetadataKind,
+ MDStringKind
+ };
+
+protected:
+ Metadata(unsigned ID, StorageType Storage)
+ : SubclassID(ID), Storage(Storage), SubclassData16(0), SubclassData32(0) {
+ }
+ ~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) const;
+ void print(raw_ostream &OS, ModuleSlotTracker &MST,
+ const Module *M = nullptr) 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;
+ /// @}
+};
+
+#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);
+ ~MetadataAsValue() override;
+
+ /// \brief Drop use of metadata (during teardown).
+ void dropUse() { MD = nullptr; }
+
+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:
+ LLVMContext &Context;
+ uint64_t NextIndex;
+ SmallDenseMap<void *, std::pair<OwnerTy, uint64_t>, 4> UseMap;
+
+public:
+ ReplaceableMetadataImpl(LLVMContext &Context)
+ : Context(Context), NextIndex(0) {}
+ ~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);
+
+ 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;
+
+ /// \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;
+ }