vela: Move special error cases

Due to an issue with potential cyclical imports, especially when running
individual parts of vela standalone for example with pytest, the
specialised error functions are moved out of errors.py to their
respective locations.
The use of getattr over isinstance prevents the need to import the
tensor/operator class causing the cyclical import issue.

Signed-off-by: Michael McGeagh <michael.mcgeagh@arm.com>
Change-Id: If8cee4b1a2562660c6a47e1c7aeb5d7fd4dd1fca

1 files changed, 29 insertions, 0 deletions

diff --git a/ethosu/vela/operation.py b/ethosu/vela/operation.py
index afc02d41..30c32acc 100644
--- a/ethosu/vela/operation.py
+++ b/ethosu/vela/operation.py
@@ -24,6 +24,7 @@ from typing import List
 from typing import Optional
 from typing import TYPE_CHECKING
 
+from .errors import VelaError
 from .numeric_util import full_shape
 
 if TYPE_CHECKING:
@@ -668,3 +669,31 @@ class Operation:
         if self.forced_output_quantization is not None:
             return self.forced_output_quantization
         return self.ofm.quantization
+
+    def error(self, msg):
+        """
+        Raises a VelaError exception for errors encountered when parsing an Operation
+
+        :param self: Operation object that resulted in the error
+        :param msg: str object that contains a description of the specific error encountered
+        """
+
+        def _print_tensors(tensors):
+            lines = []
+            for idx, tens in enumerate(tensors):
+                tens_name = getattr(tens, "name", "Not a Tensor")
+                lines.append(f"        {idx} = {tens_name}")
+            return lines
+
+        if self.op_index is None:
+            lines = [f"Invalid {self.type} (name = {self.name}) operator in the internal representation. {msg}"]
+        else:
+            lines = [f"Invalid {self.type} (op_index = {self.op_index}) operator in the input network. {msg}"]
+
+        lines += ["    Input tensors:"]
+        lines += _print_tensors(self.inputs)
+
+        lines += ["    Output tensors:"]
+        lines += _print_tensors(self.outputs)
+
+        raise VelaError("\n".join(lines))