Checking A2L File Consistency

Motivation

Syntactically valid a2l files can still contain incorrect or inconsistent content.

This can occur in several ways:

• Deleting an item that is referenced elsewhere in the file. For example, an axis may use a MEASUREMENT as an input. a2ltool can delete a referenced MEASUREMENT using the --remove command-line option.
• Adding items without including the elements they reference. With a2ltool, this may happen when using the --from-source option, as correctness depends on the input provided by the user.
• Other tools that generate a2l files may have bugs.
• The a2l file may be manually edited in a text editor, introducing errors.

Checks

With the --check option, a2ltool performs the following checks:

• Verifies all cross-references between elements.
• Ensures that various elements have mandatory or forbidden sub-elements depending on their type. For example, an AXIS_DESCR of type COM_AXIS requires an AXIS_PTS_REF. Similarly, a COMPU_METHOD of type TAB_VERB must have a COMPU_TAB_REF.
• Checks that CHARACTERISTICs have the correct number of AXIS_DESCRs based on their type.
• Validates that the lower and upper limits of elements are within the outer limits defined by their COMPU_METHOD and data type.
• Checks the group hierarchy: it must start with a group marked as ROOT and must not contain any cycles.

Usage notes

By itself, the option --check only prints a list of warnings about incorrect a2l file elements.

When used in automation, such as a Makefile or CI job, it is recommended to also use --strict, which turns warnings into errors and sets a non-zero exit status to signal the error to the environment.

The check only considers information within the a2l file. To also compare the content to the ECU software, use --update --update-mode STRICT, which raises an error if there is a mismatch between the a2l file and the debug information.

Examples

a2ltool input.a2l --verbose --check --strict

a2ltool input.a2l --elffile sw.elf --update --update-mode STRICT --check --strict