Arm backend: Move support_extension to base class (#15909)

Move support_extension to TosaSpecification base class to avoid having
to check whether the TosaSpecification is an instance of
TosaSpecification_1_00.

cc @freddan80 @per @zingo @digantdesai

Signed-off-by: Oscar Andersson <[email protected]>

Author: oscarandersson8218

backends/arm/_passes/decompose_int16_activation_conv2d_pass.py

@@ -10,7 +10,7 @@
 from executorch.backends.arm._passes.arm_pass import ArmPass
 from executorch.backends.arm._passes.quant_args import QuantArgs
 
-from executorch.backends.arm.tosa.specification import get_context_spec, Tosa_1_00
+from executorch.backends.arm.tosa.specification import get_context_spec
 from executorch.exir.dialects._ops import ops as exir_ops
 from executorch.exir.pass_base import ExportPass
 
@@ -40,9 +40,7 @@ def call_operator(self, op, args, kwargs, meta):
         if args[0].data.dtype == torch.int8:
             return super().call_operator(op, args, kwargs, meta)
         elif args[0].data.dtype == torch.int16:
-            if isinstance(tosa_spec, Tosa_1_00) and not tosa_spec.support_extension(
-                "int16"
-            ):
+            if not tosa_spec.support_extension("int16"):
                 raise ValueError(
                     "int16 activation for convolution requires TOSA int16 extension"
                 )

backends/arm/tosa/specification.py

@@ -105,6 +105,18 @@ def support_float(self) -> bool:
         """Return True if floating-point operations are supported."""
         raise NotImplementedError
 
+    def support_extension(self, extension: str) -> bool:
+        """Return True if an extension is supported and enabled.
+
+        Args:
+            extension (str): Extension name (for example ``int4``, ``bf16``).
+
+        Returns:
+            bool: True if the extension is valid for the active profiles and selected.
+
+        """
+        raise NotImplementedError
+
     def __init__(self, version: Version, extras: List[str]):
         """Initialize the base specification.