MLBEDSW-4249 Hide stack traces in error messages

When faced with an invalid tflite file we now catch the exception to
make it clear to the user that the issue is with the input and not with
Vela, instead of just crashing.
Same also applies to our own Vela error messages.

Signed-off-by: Henrik G Olsson <henrik.olsson@arm.com>
Change-Id: I56a81c5be9e1f46f3b98a88c6d24ee42fa0e450d

1 files changed, 45 insertions, 28 deletions

diff --git a/ethosu/vela/tflite_reader.py b/ethosu/vela/tflite_reader.py
index daea1bf8..b47177f7 100644
--- a/ethosu/vela/tflite_reader.py
+++ b/ethosu/vela/tflite_reader.py
@@ -16,6 +16,8 @@
 # Description:
 # Functions used to read from a TensorFlow Lite format file.
 import os.path
+import struct
+import sys
 
 import numpy as np
 
@@ -235,34 +237,49 @@ class TFLiteGraph:
         with open(filename, "rb") as f:
             buf = bytearray(f.read())
 
-        model = Model.GetRootAsModel(buf, 0)
-
-        self.buffers = []
-        for idx in range(model.BuffersLength()):
-            self.buffers.append(self.parse_buffer(model.Buffers(idx)))
-
-        self.operator_codes = []
-        for idx in range(model.OperatorCodesLength()):
-            self.operator_codes.append(self.parse_operator_code(model.OperatorCodes(idx)))
-
-        self.subgraphs = []
-        for idx in range(model.SubgraphsLength()):
-            self.subgraphs.append(TFLiteSubgraph(self, model.Subgraphs(idx)))
-
-        self.nng = Graph(self.name, self.batch_size)
-        for tflite_sg in self.subgraphs:
-            sg = Subgraph(tflite_sg.name)
-            sg.original_inputs = tflite_sg.inputs  # Preserve the original input order
-            sg.output_tensors = tflite_sg.outputs
-            self.nng.subgraphs.append(sg)
-
-        # Preserve the original metadata
-        for idx in range(model.MetadataLength()):
-            meta = model.Metadata(idx)
-            name = meta.Name()
-            if name is not None:
-                buf_data = self.buffers[meta.Buffer()]
-                self.nng.metadata.append((name, buf_data))
+        try:
+            parsing_step = "parsing root"
+            model = Model.GetRootAsModel(buf, 0)
+
+            parsing_step = "parsing buffers length"
+            self.buffers = []
+            for idx in range(model.BuffersLength()):
+                parsing_step = f"parsing buffer {idx}"
+                self.buffers.append(self.parse_buffer(model.Buffers(idx)))
+
+            parsing_step = "parsing operator codes length"
+            self.operator_codes = []
+            for idx in range(model.OperatorCodesLength()):
+                parsing_step = f"parsing operator code {idx}"
+                self.operator_codes.append(self.parse_operator_code(model.OperatorCodes(idx)))
+
+            parsing_step = "parsing subgraphs length"
+            self.subgraphs = []
+            for idx in range(model.SubgraphsLength()):
+                parsing_step = f"parsing subgraph {idx}"
+                self.subgraphs.append(TFLiteSubgraph(self, model.Subgraphs(idx)))
+
+            self.nng = Graph(self.name, self.batch_size)
+            for tflite_sg in self.subgraphs:
+                sg = Subgraph(tflite_sg.name)
+                sg.original_inputs = tflite_sg.inputs  # Preserve the original input order
+                sg.output_tensors = tflite_sg.outputs
+                self.nng.subgraphs.append(sg)
+
+            parsing_step = "parsing metadata length"
+            # Preserve the original metadata
+            for idx in range(model.MetadataLength()):
+                parsing_step = f"parsing metadata {idx}"
+                meta = model.Metadata(idx)
+                parsing_step = f"parsing metadata name of metadata {idx}"
+                name = meta.Name()
+                if name is not None:
+                    parsing_step = f"parsing metadata {idx} ({name})"
+                    buf_data = self.buffers[meta.Buffer()]
+                    self.nng.metadata.append((name, buf_data))
+        except (struct.error, TypeError, RuntimeError) as e:
+            print(f'Error: Invalid tflite file. Got "{e}" while {parsing_step}.')
+            sys.exit(1)
 
     def parse_buffer(self, buf_data):
         if buf_data.DataLength() == 0: