Remove internal executorch dependency on torchao.quantization.subclass

Differential Revision: D84921134

Pull Request resolved: #15223

Author: andrewor14

examples/models/llama/experimental/__init__.py

@@ -26,7 +26,8 @@
 from executorch.extension.gguf_util.load_gguf import GGUFWeights, load_file
 from gguf import ReaderTensor
 from gguf.constants import GGMLQuantizationType
-from torchao.quantization.subclass import QuantizedLinearWeightBase
+
+from .subclass import QuantizedLinearWeightBase
 
 FORMAT = "[%(levelname)s %(asctime)s %(filename)s:%(lineno)s] %(message)s"
 logging.basicConfig(level=logging.INFO, format=FORMAT)

examples/models/llama/experimental/load_gguf_q4_0.py

@@ -20,7 +20,11 @@
 #
 # This layout is handled internally in the tensor subclass.
 import torch
-from torchao.quantization.subclass import QuantizedLinearWeightBase
+from torch.utils._python_dispatch import return_and_correct_aliasing
+from typing_extensions import deprecated
+
+
+aten = torch.ops.aten
 
 
 def down_size(size):
@@ -129,6 +133,173 @@ def to_float(
     return a * scale.unsqueeze(1)
 
 
+@deprecated("QuantizedLinearWeightBase is deleted from torchao. DO NOT USE!")
+class QuantizedLinearWeightBase(torch.Tensor):
+    """
+    *** LEGACY TORCHAO TENSOR SUBCLASS ***
+
+    Note: this subclass no longer exists in torchao. No one should be importing or extending this
+    subclass anymore. It is added back here just for internal executorch BC. DO NOT USE!
+
+    Base quantized tensor subclass for quantized linear weights. When the from_float method is used,
+    to create an instance of any QuantizedLinearWeightBase, we assume the input
+    weight is oriented the way it is in a normal linear op, i.e. out-channels x in-channels.
+
+    The shape and dtype of the tensor subclass represent how the tensor subclass looks externally,
+    regardless of the internal representation's type or orientation.
+    """
+
+    @staticmethod
+    def __new__(cls, int_data, transposed, shape, *args, **kwargs):
+        kwargs["device"] = int_data.device
+        kwargs["layout"] = (
+            kwargs.get("layout") if kwargs.get("layout", False) else int_data.layout
+        )
+        assert "dtype" in kwargs
+        assert not kwargs.get("requires_grad", False)
+        kwargs["requires_grad"] = False
+        return torch.Tensor._make_wrapper_subclass(cls, shape, **kwargs)  # type: ignore[attr-defined]
+
+    def __init__(self, int_data, transposed, *args, **kwargs):
+        self.int_data = int_data
+
+        self.transposed = transposed
+
+    @staticmethod
+    def _quantized_op(act_mat, w_qtensor, bias):
+        pass
+
+    def __repr__(self):
+        return (
+            f"{self.__class__.__name__}(data={self.dequantize()}, shape={self.shape}, "
+            f"device={self.device}, dtype={self.dtype}, requires_grad={self.requires_grad})"
+        )
+
+    def dequantize(self):
+        pass
+
+    def int_repr(self):
+        pass
+
+    def q_params(self):
+        pass
+
+    def half(self):
+        return self.to(torch.float16)
+
+    def _get_to_kwargs(self, *args, **kwargs):
+        device, dtype, _, memory_format = torch._C._nn._parse_to(*args, **kwargs)
+        device = self.device if device is None else device
+        dtype = self.dtype if dtype is None else dtype
+        memory_format = (
+            memory_format if memory_format is not None else torch.preserve_format
+        )
+        kwargs = {
+            "device": device,
+            "dtype": dtype,
+            "memory_format": memory_format,
+        }
+        return kwargs
+
+    def _apply_fn_to_data(self, fn):
+        pass
+
+    def _change_shape(self):
+        pass
+
+    def __tensor_flatten__(self):
+        pass
+
+    @classmethod
+    def __tensor_unflatten__(
+        cls, tensor_data_dict, tensor_attributes, outer_size, outer_stride
+    ):
+        pass
+
+    @classmethod
+    def from_float(cls, input_float):
+        pass
+
+    # __torch_function__ = torch._C._disabled_torch_function_impl
+
+    @classmethod
+    def __torch_function__(cls, func, types, args=(), kwargs=None):
+        kwargs = {} if kwargs is None else kwargs
+
+        if func is torch.nn.functional.linear:
+            mat1, w_qtensor, bias = (
+                args[0],
+                args[1],
+                args[2] if len(args) > 2 else None,
+            )
+            assert not w_qtensor.transposed
+            return cls._quantized_op(mat1, w_qtensor, bias)
+
+        try:
+            with torch._C.DisableTorchFunctionSubclass():
+                return func(*args, **kwargs)
+        except Exception:
+            print(f"ERR: subclass doesn't implement {func}")
+
+    @classmethod
+    def __torch_dispatch__(cls, func, types, args, kwargs):
+        # two scenarios where we currently fall back to vanilla mm:
+        # 1 - when tensor is on CPU: we are missing qmm for CPU, but we should have a CPU implementation
+        #     for consistency and to allow people to test
+        # 2 - we're given non-floats - quantizing long to int8 is crazy
+        if (
+            func in [aten.mm.default, aten.addmm.default]
+            and args[0].is_floating_point()
+            and args[0].is_cuda
+        ):
+            if func == aten.addmm.default:
+                assert args[1].shape[-1] == args[2].shape[0], (
+                    f"need mat1 shape: {args[1].shape} final"
+                    f"dim to match mat2 shape: {args[2].shape} first dim "
+                )
+                mat1, w_qtensor, bias = (
+                    args[1],
+                    args[2],
+                    args[0],
+                )
+            else:
+                assert args[0].shape[-1] == args[1].shape[0], (
+                    f"need mat1 shape: {args[0].shape} final dim"
+                    f"to match mat2 shape: {args[1].shape} first dim"
+                )
+                mat1, w_qtensor, bias = (
+                    args[0],
+                    args[1],
+                    None if len(args) == 2 else args[2],
+                )
+            # call the quantized op for the specific type
+            # of quantized tensor subclass
+            return cls._quantized_op(mat1, w_qtensor, bias)
+
+        if func is aten.detach.default:
+            return return_and_correct_aliasing(
+                func, args, kwargs, args[0]._apply_fn_to_data(torch.detach)
+            )
+
+        if func is aten.clone.default:
+            return return_and_correct_aliasing(
+                func, args, kwargs, args[0]._apply_fn_to_data(torch.clone)
+            )
+
+        if func is aten.t.default:
+            args[0].transposed = not args[0].transposed
+            new = args[0]._change_shape(args[0].shape[::-1])
+            return return_and_correct_aliasing(func, args, kwargs, new)
+
+        if func is aten._to_copy.default:
+            return return_and_correct_aliasing(
+                func,
+                args,
+                kwargs,
+                args[0].to(*args[1:], **kwargs)._apply_fn_to_data(torch.clone),
+            )
+
+
 class GGMLInt4LinearWeight(QuantizedLinearWeightBase):
     """
     A Tensor subclass that when applied to a weight used in a linear op/module,