[Bind2] Refactor XMR references

magma/circuit.py

@@ -27,6 +27,7 @@
     pass
 
 from magma.clock import is_clock_or_nested_clock, Clock, ClockTypes
+from magma.common import only, IterableException
 from magma.config import get_debug_mode, set_debug_mode, config, RuntimeConfig
 from magma.definition_context import (
     DefinitionContext,
@@ -40,7 +41,6 @@
 from magma.protocol_type import MagmaProtocol
 from magma.ref import TempNamedRef, AnonRef
 from magma.t import In, Type
-from magma.view import PortView
 from magma.wire_container import WiringLog, AggregateWireable
 
 
@@ -735,6 +735,21 @@ def __new__(metacls, name, bases, dct):
 
         return self
 
+    def __getattr__(self, attr):
+        error = None
+        try:
+            return object.__getattribute__(self, attr)
+        except AttributeError as e:
+            # NOTE(rsetaluri): The scope of `e` is only within this `except`
+            # block. Therefore we have to stash it in a local variable to be
+            # able to raise it later.
+            error = e
+        try:
+            return only(filter(lambda i: i.name == attr, self.instances))
+        except IterableException:
+            pass
+        raise error from None
+
     @property
     def is_definition(self):
         return self._is_definition or self.verilog or self.verilogFile

tests/test_bind2.py

@@ -58,13 +58,14 @@ class TopBasicAsserts(m.Circuit):
 
 
 @pytest.mark.parametrize(
-    "backend,flatten_all_tuples",
+    "backend,flatten_all_tuples,inst_attr",
     (
-        ("mlir", True),
-        ("mlir", False),
+        ("mlir", False, False),
+        ("mlir", True, False),
+        ("mlir", True, True),
     )
 )
-def test_xmr(backend, flatten_all_tuples):
+def test_xmr(backend, flatten_all_tuples, inst_attr):
 
     class T(m.Product):
         x = m.Bit
@@ -80,8 +81,12 @@ class Middle(m.Circuit):
 
     class Top(m.Circuit):
         io = m.IO(I=m.In(T), O=m.Out(T))
-        middle = Middle(name="middle")
-        io.O @= middle(io.I)
+        if inst_attr:
+            middle = Middle(name="middle")
+            O = middle(io.I)
+        else:
+            O = Middle(name="middle")(io.I)
+        io.O @= O
 
     class TopXMRAsserts(m.Circuit):
         name = f"TopXMRAsserts_{backend}"

tests/test_circuit/test_instance.py

@@ -1,6 +1,7 @@
 import pytest
 
 import magma as m
+from magma.common import only
 
 
 def test_callback_basic():
@@ -36,3 +37,34 @@ class _Test(m.Circuit):
     m.register_instance_callback(_Test.reg, lambda _, __: None)
     with pytest.raises(AttributeError):
         m.register_instance_callback(_Test.reg, lambda _, __: None)
+
+
+def test_getattr_instance_name():
+    Bar = m.Register(m.Bit)  # just any module
+
+    class Foo(m.Circuit):
+        my_placeholder_var = Bar(name="my_instance_name")
+
+    assert Foo.my_placeholder_var is Foo.my_instance_name
+
+
+def test_getattr_instance_name_overwritten():
+    Bar = m.Register(m.Bit)  # just any module
+
+    class Foo(m.Circuit):
+        my_placeholder_var = Bar(name="my_instance_name")
+        my_instance_name = None
+
+    assert Foo.my_instance_name is None
+    assert Foo.my_placeholder_var is only(Foo.instances)
+
+
+def test_getattr_attribute_error():
+
+    class Foo(m.Circuit):
+        pass
+
+    with pytest.raises(AttributeError) as e:
+        Foo.bar
+
+    assert "has no attribute 'bar'" in str(e)