[MLIR] Add support for Tuples with integer keys (#1260)

* [MLIR] Prefix tuple field keys with _

See #1252.

* [MLIR] Factor out magma tuple key to string logic

magma/backend/mlir/hardware_module.py

@@ -25,6 +25,7 @@
     value_or_type_to_string as magma_value_or_type_to_string,
     visit_value_or_value_wrapper_by_direction as
     visit_magma_value_or_value_wrapper_by_direction,
+    tuple_key_to_str as magma_tuple_key_to_str,
 )
 from magma.backend.mlir.mem_utils import (
     make_mem_reg,
@@ -139,9 +140,11 @@ def magma_type_to_mlir_type(type: Kind) -> MlirType:
             return magma_type_to_mlir_type(Bits[type.N])
         return hw.ArrayType((type.N,), magma_type_to_mlir_type(type.T))
     if issubclass(type, m_Tuple):
-        fields = {str(k): magma_type_to_mlir_type(t)
-                  for k, t in type.field_dict.items()}
-        return hw.StructType(tuple(fields.items()))
+        fields = (
+            (magma_tuple_key_to_str(k, type), magma_type_to_mlir_type(t))
+            for k, t in type.field_dict.items()
+        )
+        return hw.StructType(tuple(fields))
 
 
 @wrap_with_not_implemented_error
@@ -969,7 +972,10 @@ def visit_instance_wrapper(self, module: ModuleWrapper) -> bool:
             )
             return True
         if inst_wrapper.name.startswith("magma_tuple_get_op"):
-            index = inst_wrapper.attrs["index"]
+            index = magma_tuple_key_to_str(
+                inst_wrapper.attrs["index"],
+                inst_wrapper.attrs["T"]
+            )
             hw.StructExtractOp(
                 field=index,
                 operands=module.operands,

magma/backend/mlir/magma_common.py

@@ -8,7 +8,7 @@
 from magma.common import replace_all, Stack, SimpleCounter
 from magma.ref import Ref, ArrayRef, TupleRef
 from magma.t import Kind, Type
-from magma.tuple import TupleMeta, Tuple as m_Tuple
+from magma.tuple import TupleMeta, Tuple as m_Tuple, Product
 
 
 ModuleLike = Union[DefineCircuitKind, Circuit]
@@ -42,6 +42,15 @@ def value_or_type_to_string(value_or_type: Union[Type, Kind]):
     return replace_all(s, _VALUE_OR_TYPE_TO_STRING_REPLACEMENTS)
 
 
+def tuple_key_to_str(key: Union[str, int], T: TupleMeta) -> str:
+    # NOTE(rsetaluri): If the type is Tuple (i.e. has integer keys), then the
+    # struct type we emit should prefix the field key with an underscore
+    # (e.g. "_0") to make it a valid keyword.
+    if issubclass(T, Product):
+        return str(key)
+    return f"_{key}"
+
+
 @dataclasses.dataclass(frozen=True)
 class ValueWrapper:
     id: str = dataclasses.field(default_factory=make_unique_name, init=False)

tests/test_backend/test_mlir/golds/simple_aggregates_tuple.mlir

@@ -1,11 +1,11 @@
 module attributes {circt.loweringOptions = "locationInfoStyle=none"} {
-    hw.module @simple_aggregates_tuple(%a: !hw.struct<0: i8, 1: i8>) -> (y: !hw.struct<0: i8, 1: i8>) {
-        %0 = hw.struct_extract %a["0"] : !hw.struct<0: i8, 1: i8>
+    hw.module @simple_aggregates_tuple(%a: !hw.struct<_0: i8, _1: i8>) -> (y: !hw.struct<_0: i8, _1: i8>) {
+        %0 = hw.struct_extract %a["_0"] : !hw.struct<_0: i8, _1: i8>
         %2 = hw.constant -1 : i8
         %1 = comb.xor %2, %0 : i8
-        %3 = hw.struct_extract %a["1"] : !hw.struct<0: i8, 1: i8>
+        %3 = hw.struct_extract %a["_1"] : !hw.struct<_0: i8, _1: i8>
         %4 = comb.xor %2, %3 : i8
-        %5 = hw.struct_create (%1, %4) : !hw.struct<0: i8, 1: i8>
-        hw.output %5 : !hw.struct<0: i8, 1: i8>
+        %5 = hw.struct_create (%1, %4) : !hw.struct<_0: i8, _1: i8>
+        hw.output %5 : !hw.struct<_0: i8, _1: i8>
     }
 }

tests/test_backend/test_mlir/golds/simple_aggregates_tuple.v

@@ -0,0 +1,9 @@
+// Generated by CIRCT circtorg-0.0.0-1773-g7abbc4313
+module simple_aggregates_tuple(
+  input  struct packed {logic [7:0] _0; logic [7:0] _1; } a,
+  output struct packed {logic [7:0] _0; logic [7:0] _1; } y
+);
+
+  assign y = '{_0: (~a._0), _1: (~a._1)};
+endmodule
+

tests/test_backend/test_mlir/test_compile_to_mlir_local_examples.py

@@ -43,11 +43,6 @@ def test_compile_to_mlir(ckt):
         "use_native_bind_processor": True,
         "basename": ckt.name,
     }
-    # NOTE(rsetaluri): This is a hack to skip the Tuple[] to verilog test since
-    # MLIR does not allow leading integers in names (e.g. `!hw.struct<0:
-    # ...>`). We should ultimately fix this by changing the IR code generation.
-    if ckt.name == "simple_aggregates_tuple":
-        kwargs["check_verilog"] = False
     run_test_compile_to_mlir(ckt, **kwargs)