Create the Rank and IsScalar shared functions | feat(torchlib) (#1105)

This change introduces two shared operators `Rank` and `IsScalar`. They
are used to replace the `Size(Shape())` pattern for code reuse and
readability.

I used a hack to always include these shared functions in the model
proto because without #834 we cannot dynamically add these functions to
the model as they are used. I added a TODO for this.

The first usage is in `aten_all`. I will update the rest of the
functions in a separate PR.

#1095

onnxscript/function_libs/tools/torch_lib/deduce_type_constraints_test.py

@@ -30,7 +30,7 @@ class TestDeduceTypeConstraints(unittest.TestCase):
         "_aten_embedding_bag_onnx",
         "_aten_embedding_bag_1d_padding_idx_onnx",
     )
-    _SKIP_FUNCTIONS_WITH_NESTED_FUNCTION = ()
+    _SKIP_FUNCTIONS_WITH_NESTED_FUNCTION = ("aten_all",)
 
     @parameterized.parameterized.expand(
         ((op,) for op in torch_lib_onnx_functions_from_registry()),

onnxscript/function_libs/torch_lib/_constants.py

@@ -0,0 +1,3 @@
+"""Shared constants for the library."""
+
+DOMAIN = "pkg.onnxscript.torch_lib"

onnxscript/function_libs/torch_lib/graph_building.py

@@ -21,6 +21,7 @@
 from onnxscript import evaluator
 from onnxscript import tensor as onnxscript_tensor
 from onnxscript._internal import param_manipulation, runtime_typing
+from onnxscript.function_libs.torch_lib.ops import common as common_ops
 
 __all__ = [
     "TorchScriptTensor",
@@ -363,6 +364,16 @@ def _tensor_rawdata_size(tensor: torch.Tensor) -> int:
     return tensor.numel() * tensor.element_size()
 
 
+def _shared_functions() -> list[onnx.FunctionProto]:
+    """Hack to always include the share ops."""
+
+    # TODO: Remove after https://github.com/microsoft/onnxscript/issues/834 is fixed
+    return [
+        common_ops.Rank.to_function_proto(),
+        common_ops.IsScalar.to_function_proto(),
+    ]
+
+
 class TorchScriptGraph:
     def __init__(
         self,
@@ -717,7 +728,6 @@ def to_function_proto(self, opset_version: int, function_name: str) -> onnx.Func
             opset_imports=onnx_model.opset_import,
             doc_string=onnx_model.doc_string,
         )
-        # TODO: onnx.checker.check_function(onnx_function)?
         return onnx_function
 
     @runtime_typing.checked
@@ -786,6 +796,7 @@ def to_model_proto(
             onnx_model = onnx.load_from_string(proto)
 
         onnx_model.functions.extend(function_proto_dict.values())
+        onnx_model.functions.extend(_shared_functions())
 
         # `_export_onnx` only exports opset_imports that is visible to it. It does not
         # export opset_imports for nested functions, since it does not have access to
@@ -800,6 +811,13 @@ def to_model_proto(
                 for domain, version in unique_custom_domains.items()
             ]
         )
+        # Include the library shared opset domain
+        # TODO: Remove after https://github.com/microsoft/onnxscript/issues/834 is fixed
+        onnx_model.opset_import.append(
+            onnx.helper.make_opsetid(
+                common_ops.common_opset.domain, common_ops.common_opset.version
+            )
+        )
 
         try:
             if not cache_model_to_disk:

onnxscript/function_libs/torch_lib/ops/common.py

@@ -0,0 +1,25 @@
+"""Common operators shared in the torchlib library."""
+
+import onnxscript
+import onnxscript.values
+from onnxscript import BOOL, INT64
+from onnxscript import opset18 as op
+from onnxscript.function_libs.torch_lib import _constants, tensor_typing
+
+DOMAIN = f"{_constants.DOMAIN}.common"
+
+common_opset = onnxscript.values.Opset(domain=DOMAIN, version=1)
+
+
+@onnxscript.script(common_opset)
+def Rank(input: tensor_typing.TTensor) -> INT64:
+    """Take the rank of the input tensor."""
+
+    return op.Size(op.Shape(input))
+
+
+@onnxscript.script(common_opset)
+def IsScalar(input: tensor_typing.TTensor) -> BOOL:
+    """Return whether the input has rank 0, or is a scalar."""
+
+    return op.Equal(op.Size(op.Shape(input)), op.Constant(value_int=0))

onnxscript/function_libs/torch_lib/ops/core.py

@@ -30,6 +30,7 @@
     UINT64,
     graph,
 )
+from onnxscript.function_libs.torch_lib.ops import common as common_ops
 from onnxscript.function_libs.torch_lib.registration import torch_op
 from onnxscript.function_libs.torch_lib.tensor_typing import (
     IntType,
@@ -52,6 +53,8 @@
 _INT64_MAX = 9223372036854775807
 _INT64_MIN = -9223372036854775808
 _MATH_PI = math.pi
+IsScalar = common_ops.IsScalar
+Rank = common_ops.Rank
 
 
 @torch_op("aten::_local_scalar_dense")
@@ -320,8 +323,7 @@ def aten_align_to(self: TensorType, names: Sequence[str]) -> TensorType:
 def aten_all(self: TTensor) -> BOOL:
     """all(Tensor self) -> Tensor"""
 
-    self_rank = op.Size(op.Shape(self))
-    if self_rank == 0:
+    if IsScalar(self):
         result = op.Cast(self, to=BOOL.dtype)
     else:
         self_bool = op.Cast(self, to=BOOL.dtype)

onnxscript/function_libs/torch_lib/registration.py

@@ -7,6 +7,7 @@
 from typing import Any, Callable, Generator, Optional
 
 import onnxscript
+from onnxscript.function_libs.torch_lib import _constants
 
 # Regex that will match "<namespace>::<op_name>[.<overload>]"
 _QUALIFIED_OPERATOR_NAME_REGEX = re.compile(
@@ -119,7 +120,7 @@ def wrapper(
         func: FunctionType,
     ) -> onnxscript.OnnxFunction | onnxscript.values.TracedOnnxFunction:
         # Compile the function
-        custom_opset = onnxscript.values.Opset(domain="pkg.onnxscript.torch_lib", version=1)
+        custom_opset = onnxscript.values.Opset(domain=_constants.DOMAIN, version=1)
 
         processed_func: onnxscript.OnnxFunction | onnxscript.values.TracedOnnxFunction
         if trace_only: