Files
xc-llm-ascend/vllm_ascend/meta_registration.py
SILONG ZENG 52086394ae [Lint]Style: Convert vllm-ascend/compilation to ruff format (#5912)
### What this PR does / why we need it?
Convert `vllm-ascend/compilation` to ruff format.

### Does this PR introduce _any_ user-facing change?
During this migration, we encountered some **errors** in our CI and
testing environments, such as:
```
vllm_ascend/utils.py:653: in <module>
    def register_ascend_customop(vllm_config: VllmConfig | None = None):
                                              ^^^^^^^^^^^^^^^^^
E   TypeError: unsupported operand type(s) for |: 'NoneType' and 'NoneType'
```

**1. Root Cause Analysis:**
The project uses a common pattern to break circular dependencies:
```python
if TYPE_CHECKING:
    from vllm.config import VllmConfig
else:
    VllmConfig = None  # Placeholder assigned at runtime
```
When Python parses the function definition `def
register_ascend_customop(vllm_config: VllmConfig | None)`, it attempts
to evaluate the expression `VllmConfig | None`.
Since `VllmConfig` is assigned `None` at runtime, the expression
effectively becomes `None | None`. In Python, `None` is an instance of
`NoneType`. While the `|` operator is implemented for Type objects
(classes), it is not supported for `NoneType` instances, leading to the
`TypeError` shown above.

**2. Solution:**
To maintain the modern `|` syntax required by our new linting standards
while preserving our dependency management strategy, I have introduced:
```python
from __future__ import annotations
```
at the top of the affected files. This enables **Postponed Evaluation of
Annotations (PEP 563)**.

**3. Impact and Benefits:**
- By enabling `annotations`, Python no longer executes the `VllmConfig |
None` operation during module load. Instead, it stores the annotation as
a string literal, completely avoiding the `None | None` calculation.
- We can keep the `VllmConfig = None` placeholders. This ensures that
other modules can still import these symbols without triggering an
`ImportError`, maintaining a stable dependency graph.
- IDEs and static type checkers (MyPy/Pyright) continue to resolve the
types correctly. This allows us to use modern syntax without sacrificing
type safety or runtime stability.
- The only side effect is that `__annotations__` will now return strings
instead of type objects. Since this module does not use runtime type
enforcement or reflection, this change has zero negative impact on
existing functionality.
### How was this patch tested?

- vLLM version: v0.13.0
- vLLM main:
11b6af5280

---------

Signed-off-by: MrZ20 <2609716663@qq.com>
2026-01-16 20:57:46 +08:00

112 lines
4.2 KiB
Python

import torch
from torch.library import Library
# This file provides a template and registration utilities for writing "meta" implementations
# of custom operators in Python for the vllm_ascend project.
#
# We offer two ways to implement meta implementations for custom ops:
# 1. Python meta implementation (as shown in this file): Write a Python function that
# takes the same arguments as your operator and returns empty tensors with the correct
# shapes and dtypes. This is useful for rapid prototyping and for ops that are only
# used in Python.
# 2. C++ meta implementation: You can also implement the meta function in C++ for better
# performance or to match the C++ op logic more closely. See `torch_binding_meta.cpp`
# for examples of C++ meta implementations and how to register them.
#
# Both approaches enable tracing, export, and shape inference in PyTorch and vLLM, which
# is essential for supporting `torch.compile` and aclgraph.
# How to add a new meta implementation in Python:
# -------------------------------------
# 1. Write a Python function that takes the same arguments as your operator, and returns
# empty tensors (using torch.empty_like, torch.empty, etc.) with the correct shapes and dtypes.
# Do NOT perform any real computation or allocate device memory.
#
# 2. Register your meta function using `register_meta_if_necessary`, providing:
# - The namespace (usually "_C_ascend" for custom ops)
# - The operator name (as registered in C++)
# - The Python meta function
# - (Optional) The overload name, if your op has overloads
#
# 3. The registration utility will check if a meta implementation already exists for your op,
# and only register if necessary. This avoids duplicate registrations.
#
# 4. Example meta implementations are provided below for rotary_embedding and get_masked_input_and_mask.
#
# 5. When developing new custom ops, always provide a meta implementation to enable tracing,
# export, and shape inference in PyTorch and vLLM to enable the capture of `torch.compile`
# and aclgraph.
#
# For more details, see: https://pytorch.org/docs/stable/notes/extending.html#meta-tensors
lib = Library("_C_ascend", "IMPL")
def register_meta_if_necessary(ns: str, op_name: str, fn, overload: str = ""):
if overload != "":
op_name = op_name + "." + overload
schema_to_find = ns + "::" + op_name
meta_impl_list = torch._C._dispatch_get_registrations_for_dispatch_key("Meta")
if schema_to_find in meta_impl_list:
return
lib.impl(op_name, fn, "Meta")
def rotary_embedding_meta(
positions: torch.Tensor,
query: torch.Tensor,
key: torch.Tensor,
head_size: int,
cos_sin_cache: torch.Tensor,
is_neox: bool,
):
num_tokens = positions.numel()
query_hidden_size = query.numel() // num_tokens
key_hidden_size = key.numel() // num_tokens
num_heads = query_hidden_size // head_size
num_kv_heads = key_hidden_size // head_size
query_dst = torch.empty_like(query).view(num_tokens, num_heads, head_size)
key_dst = torch.empty_like(key).view(num_tokens, num_kv_heads, head_size)
return query_dst, key_dst
def get_masked_input_and_mask_meta(
input: torch.Tensor,
org_vocab_start_index: int,
org_vocab_end_index: int,
num_org_vocab_padding: int,
added_vocab_start_index: int,
added_vocab_end_index: int,
):
masked_input = torch.empty_like(input)
mask = torch.empty_like(input).to(torch.bool)
return masked_input, mask
def bgmv_expand_meta(
x: torch.Tensor, weight: torch.Tensor, indices: torch.Tensor, y: torch.Tensor, slice_offset: int, slice_size: int
):
y_out = torch.empty_like(y)
return y_out
def sgmv_expand_meta(
x: torch.Tensor,
weight: torch.Tensor,
lora_indices: torch.Tensor,
seq_len: torch.Tensor,
y: torch.Tensor,
slice_offset: int,
slice_size: int,
):
y_out = torch.empty_like(y)
return y_out
register_meta_if_necessary("_C_ascend", "rotary_embedding", rotary_embedding_meta)
register_meta_if_necessary("_C_ascend", "get_masked_input_and_mask", get_masked_input_and_mask_meta)
register_meta_if_necessary("_C_ascend", "bgmv_expand", bgmv_expand_meta)
register_meta_if_necessary("_C_ascend", "sgmv_expand", sgmv_expand_meta)