Module rustc_data_structures::tagged_ptr

This module implements tagged pointers.

In order to utilize the pointer packing, you must have two types: a pointer, and a tag.

The pointer must implement the Pointer trait, with the primary requirement being convertible to and from a raw pointer. Note that the pointer must be dereferenceable, so raw pointers generally cannot implement the Pointer trait. This implies that the pointer must also be non-null.

Many common pointer types already implement the Pointer trait.

The tag must implement the Tag trait.

We assert that the tag and the Pointer types are compatible at compile time.

Modules

• copy 🔒
• drop 🔒
• impl_tag 🔒

Structs

• CopyTaggedPtr
  A Copy tagged pointer.
• TaggedPtr
  A tagged pointer that supports pointers that implement Drop.

Traits

• Pointer
  This describes the pointer type encapsulated by TaggedPtr and CopyTaggedPtr.
• Tag
  This describes tags that the TaggedPtr struct can hold.

Functions

• bits_for
  Returns the number of bits available for use for tags in a pointer to T (this is based on T’s alignment).
• bits_for_tags
  Returns the correct Tag::BITS constant for a set of tag values.