[#llvm-ValueAsMetadata]
= xref:llvm.adoc[llvm]::ValueAsMetadata
:relfileprefix: ../
:mrdocs:

Value wrapper in the Metadata hierarchy.

== Synopsis

Declared in `<llvm/IR/Metadata.h>`

[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
class ValueAsMetadata
    : public xref:llvm/Metadata.adoc[Metadata]
----

== Description

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 _ValueAsMetadata_ object, so the lookup maps are far more efficient than those using ValueHandleBase.

== Base Classes

[cols="1,4"]
|===
| Name| Description
| `xref:llvm/Metadata.adoc[Metadata]`
| Root of the metadata hierarchy.
|===

== Enums

[cols="1,4"]
|===
| Name| Description
| xref:llvm/Metadata/MetadataKind.adoc[`MetadataKind`] 
| RTTI identifiers for concrete metadata subclasses.
|===


== Member Functions

[cols="1,4"]
|===
| Name| Description
| xref:llvm/Metadata/dump-08.adoc[`dump`] 
| `dump` overloads
| xref:llvm/ValueAsMetadata/getAllArgListUsers.adoc[`getAllArgListUsers`] 
| Return all `DIArgList` users of this replaceable metadata.
| xref:llvm/ValueAsMetadata/getAllDbgVariableRecordUsers.adoc[`getAllDbgVariableRecordUsers`] 
| Return all `DbgVariableRecord` users of this replaceable metadata.
| xref:llvm/ValueAsMetadata/getContext.adoc[`getContext`] 
| Return the LLVM context of the wrapped value.
| xref:llvm/Metadata/getMetadataID.adoc[`getMetadataID`] 
| Return the metadata kind ID for this node.
| xref:llvm/ValueAsMetadata/getType.adoc[`getType`] 
| Return the type of the wrapped IR value.
| xref:llvm/ValueAsMetadata/getValue.adoc[`getValue`] 
| Return the wrapped IR value.
| xref:llvm/Metadata/print-0c.adoc[`print`] 
| `print` overloads
| xref:llvm/Metadata/printAsOperand-09e.adoc[`printAsOperand`] 
| `printAsOperand` overloads
|===


== Static Member Functions

[cols="1,4"]
|===
| Name| Description
| xref:llvm/ValueAsMetadata/classof.adoc[`classof`] 
| Methods for support type inquiry through isa, cast, and dyn_cast.
| xref:llvm/ValueAsMetadata/get.adoc[`get`] 
| Create or return value‐as‐metadata wrapping `V.`
| xref:llvm/ValueAsMetadata/getConstant.adoc[`getConstant`] 
| Return constant‐as‐metadata for constant value `C.`
| xref:llvm/ValueAsMetadata/getConstantIfExists.adoc[`getConstantIfExists`] 
| Return existing constant‐as‐metadata for `C,` or null if none.
| xref:llvm/ValueAsMetadata/getIfExists.adoc[`getIfExists`] 
| Return existing value‐as‐metadata for `V,` or null if none.
| xref:llvm/ValueAsMetadata/getLocal.adoc[`getLocal`] 
| Return local‐as‐metadata wrapping a function‐local value.
| xref:llvm/ValueAsMetadata/getLocalIfExists.adoc[`getLocalIfExists`] 
| Return local‐as‐metadata for `Local` if it already exists, else null.
| xref:llvm/ValueAsMetadata/handleDeletion.adoc[`handleDeletion`] 
| Remove and delete `ValueAsMetadata` for `V` when `V` is destroyed.
| xref:llvm/ValueAsMetadata/handleRAUW.adoc[`handleRAUW`] 
| Update metadata after `From` is RAUW'd to `To.`
|===


== Static Data Members

[cols="1,4"]
|===
| Name| Description
| xref:llvm/Metadata/PoisonGeneratingIDs.adoc[`PoisonGeneratingIDs`] 
| Metadata IDs that may generate poison.
|===


== Protected Enums

[cols="1,4"]
|===
| Name| Description
| xref:llvm/Metadata/StorageType.adoc[`StorageType`] 
| Active type of storage.
|===


== Protected Member Functions

[cols="1,4"]
|===
| Name| Description
| xref:llvm/ValueAsMetadata/2constructor.adoc[`ValueAsMetadata`]         [.small]#[constructor]#
| Construct value‐as‐metadata wrapping `V` with subclass ID `ID.`
| xref:llvm/ValueAsMetadata/2destructor.adoc[`~ValueAsMetadata`] [.small]#[destructor]#
| Destroy this value‐as‐metadata wrapper.
| xref:llvm/Metadata/handleChangedOperand.adoc[`handleChangedOperand`] 
| Default handling of a changed operand, which asserts.
| xref:llvm/ValueAsMetadata/replaceAllUsesWith.adoc[`replaceAllUsesWith`] 
| Handle collisions after _Value::replaceAllUsesWith()._
|===


== Protected Data Members

[cols="1,4"]
|===
| Name| Description
| xref:llvm/Metadata/Storage.adoc[`Storage`] 
| Storage flag for non‐uniqued, otherwise unowned, metadata.
| xref:llvm/Metadata/SubclassData1.adoc[`SubclassData1`] 
| One bit of subclass‐specific state packed into the metadata header.
| xref:llvm/Metadata/SubclassData16.adoc[`SubclassData16`] 
| Sixteen bits of subclass‐specific state packed into the metadata header.
| xref:llvm/Metadata/SubclassData32.adoc[`SubclassData32`] 
| Thirty‐two bits of subclass‐specific state packed into the metadata header.
|===


== Friends

[cols="1,4"]
|===
| Name| Description
| `xref:llvm/LLVMContextImpl.adoc[llvm::LLVMContextImpl]`
| Private implementation details of `LLVMContext.`
| `xref:llvm/ReplaceableMetadataImpl.adoc[llvm::ReplaceableMetadataImpl]`
| Shared implementation of use‐lists for replaceable metadata.
|===

== Non-Member Functions

[cols="1,4"]
|===
| Name| Description
| xref:llvm/MapMetadata-00.adoc[`MapMetadata`]
| Lookup or compute a mapping for a piece of metadata.
| xref:llvm/wrap-057.adoc[`wrap`]
| Wrap a `Metadata` pointer as an opaque `LLVMMetadataRef.`
|===

== Derived Classes

[cols="1,4"]
|===
| Name| Description
| xref:llvm/ConstantAsMetadata.adoc[`ConstantAsMetadata`] 
| Metadata wrapping a constant IR value.
| xref:llvm/LocalAsMetadata.adoc[`LocalAsMetadata`] 
| Metadata wrapping a function‐local (non‐constant) IR value.
|===


[.small]#Created with https://www.mrdocs.com[MrDocs]#