# Deprecation Notices

This section contains information about deprecation of behaviours, features and APIs that have become undesirable/obsolete. Any information about the schedule for their deprecation and reasoning behind the changes, along with examples, is provided.

## Deprecation of LLVM initialization

A breaking change has occurred with the upgrade to LLVM 20. Initialization of LLVM core is now automatic, and `llvm.binding.initialize()` will raise a `RuntimeError` with a suitable message. LLVM 20 includes many behavior changes that may break user code or expectations. This hard error warns users of such potential breakage. See LLVM 20 (llvmlite 0.45+) for more details on LLVM 20 changes.

### Reason for deprecation

This is an unscheduled deprecation due to removal of the underlying API in LLVM 20.

### Schedule

- In llvmlite 0.45, `llvm.binding.initialize()` will raise a hard error to notify users of the breaking change.

- In llvmlite 0.46, `llvm.binding.initialize()` will be removed.

### Recommendations

Simply remove `llvm.binding.initialize()`.

## Deprecation of Typed Pointers

Note

Typed pointers support has been removed as llvmlite now uses LLVM 20, which dropped support for typed pointers. All pointer operations now use opaque pointers. See the migration guide below for updating existing code.

The use of Typed Pointers is deprecated, and Opaque Pointers will be the default (and eventually required) in a future llvmlite version.

### Reason for deprecation

llvmlite aims to move forward to newer LLVM versions, which will necessitate switching to Opaque Pointers:

- In LLVM 15, Opaque Pointers are the default.

- In LLVM 16, Typed Pointers are only supported on a best-effort basis (and therefore may have bugs that go unfixed).

- In LLVM 17, support for Typed Pointers is removed.

Although Opaque Pointers are already the default in LLVM 15, llvmlite still used Typed Pointers by default with LLVM 15 in llvmlite 0.44.

The binding layer will move to using Opaque Pointers. The IR layer will still support both Typed and Opaque Pointers, defaulting to Typed Pointers when pointee types are provided. This allows llvmlite to continue being used with LLVM-based projects that use an older LLVM version, such as NVVM.

### Examples(s) of the impact

In a future release, code that uses llvmlite to work with Typed Pointers or generate IR with Typed Pointers will break if not modified to use Opaque Pointers.

In the meantime, IR generated by the IR layer and parsed by the binding layer will be auto-upgraded to use Opaque Pointers transparently; no action is required by the user.

### Schedule

- In llvmlite 0.45, support for Typed Pointers in the binding layer was removed. The IR layer will still use Typed Pointers by default.

- In a future version of llvmlite (>= 0.46), the IR layer will use Opaque Pointers by default.

- In a subsequent version of llvmlite (>= 0.47), support for Typed Pointers at the IR layer will be removed.

This schedule may be updated to push out the deprecation / removal of Typed Pointer support to still later versions of llvmlite.

### Recommendations

Code using llvmlite should be updated as follows when switching to Opaque Pointers.

#### IR layer

Modify uses of `.type.pointee` of instructions to use `.allocated_type` instead. For example:

    # Allocating an integer on the stack and storing a value to it
    stackint = builder.alloca(ir.IntType(32))
    builder.store(ir.Constant(stackint.type.pointee, 123), stackint)

becomes:

    # Allocating an integer on the stack and storing a value to it
    stackint = builder.alloca(ir.IntType(32))
    builder.store(ir.Constant(stackint.allocated_type, 123), stackint)

Replace the use of `.as_pointer()` of types with the `PointerType` class. For example:

    # Declaring a function of type i32(i32*, i32)
    fnty = ir.FunctionType(ir.IntType(32), [ir.IntType(32).as_pointer(),
                           ir.IntType(32)])

becomes:

    # Declaring a function of type i32(ptr, i32)
    fnty = ir.FunctionType(ir.IntType(32), [ir.PointerType(),
                           ir.IntType(32)])

Modify calls to `ir.load`, `ir.load_atomic`, and `ir.gep` instructions to pass in pointer types. For example:

    ptr = builder.gep(func.args[0], [index])
    value = builder.load(ptr)

becomes:

    ptr = builder.gep(func.args[0], [index], source_etype=ll.IntType(32))
    value = builder.load(ptr, typ=ll.IntType(32))

#### Binding layer

When working with `TargetData` instances:

- Replace calls to `get_pointee_abi_size()` with calls to `get_abi_size()`.

- Replace calls to `get_pointee_abi_alignment()` with calls to `get_abi_alignment()`.

When working with global variables and functions (which will be `ValueRef` instances):

- Replace any use of `valueref.type` with `valueref.global_value_type` for any `valueref` that is a global variable or function.

When passing assembly to `llvmlite.binding.parse_assembly()`:

- IR passed to `parse_assembly()` is free to use either Typed or Opaque Pointers.