[Wave] Remove unused code from iree/turbine/support (#44)

Also move used functions from the deleted files
into where they are being used.

Signed-off-by: Harsh Menon <[email protected]>

Author: harsh-nod

iree/turbine/runtime/device.py

@@ -36,11 +36,27 @@
     torch_dtype_to_numpy,
 )
 
-from ..support.exceptions import (
-    NoCurrentDeviceError,
-    MismatchedDeviceSetClearError,
-    UnsupportedTorchDeviceError,
-)
+
+class NoCurrentDeviceError(Exception):
+    def __init__(self):
+        super().__init__(
+            "You accessed a method which requires a current device but none was set on this thread. "
+            "Either pass an explicit 'device=' or set a current device via "
+            "`with device:`"
+        )
+
+
+class MismatchedDeviceSetClearError(AssertionError):
+    def __init__(self):
+        super().__init__("Calls to Device.set()/clear() are mismatched or unbalanced.")
+
+
+class UnsupportedTorchDeviceError(Exception):
+    def __init__(self, torch_device):
+        super().__init__(
+            f"Attempt to use turbine with a torch.device that is not supported by this build: {torch_device}"
+        )
+
 
 from ..support.logging import runtime_logger as logger
 

iree/turbine/support/__init__.py

@@ -6,4 +6,3 @@
 
 # Debugging must be loaded first as other low level things depend on it.
 from .debugging import *
-from .exceptions import *

iree/turbine/support/conversions.py

@@ -18,9 +18,12 @@
     TORCH_DTYPE_TO_MLIR_TYPE_ASM,
 )
 
-from .exceptions import (
-    UnknownDTypeError,
-)
+
+class UnknownDTypeError(ValueError):
+    def __init__(self, dtype):
+        self.dtype = dtype
+        super().__init__(f"Unable to map torch dtype {dtype} to Turbine")
+
 
 from .ir_imports import (
     Float8E4M3FNUZType,