ldgen: Improve error output when linker input is invalid, don't create output file until end of process

tools/ldgen/common.py

@@ -0,0 +1,23 @@
+#
+# Copyright 2018-2019 Espressif Systems (Shanghai) PTE LTD
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+
+class LdGenFailure(RuntimeError):
+    """
+    Parent class for any ldgen runtime failure which is due to input data
+    """
+    def __init__(self, message):
+        super(LdGenFailure, self).__init__(message)