Re: [RFC PATCH] xen/build: Add cppcheck and cppcheck-html make rules

[Stefano Stabellini <sstabellini@xxxxxxxxxx>]

On Thu, 24 Mar 2022, Bertrand Marquis wrote:
> cppcheck can be used to check Xen code quality.
> 
> To create a report do "make cppcheck" on a built tree adding any options
> you added during the process you used to build xen (like CROSS_COMPILE
> or XEN_TARGET_ARCH). This will generate an xml report xen-cppcheck.xml.
> 
> To create a html report do "make cppcheck-html" in the same way and a
> full report to be seen in a browser will be generated in
> cppcheck-htmlreport/index.html.
> 
> For better results it is recommended to build your own cppcheck from the
> latest sources that you can find at [1].
> Development and result analysis has been done with cppcheck 2.7.
> 
> The Makefile rule is searching for all C files which have been compiled
> (ie which have a generated .o file) and is running cppcheck on all of
> them using the current configuration of xen so only the code actually
> compiled is checked.
> 
> A new tool is introduced to merge all cppcheck reports into one global
> report including all findings and removing duplicates.
> 
> Some extra variables can be used to customize the report:
> - CPPCHECK can be used to give the full path to the cppcheck binary to
> use (default is to use the one from the standard path).
> - CPPCHECK_HTMLREPORT can be used to give the full path to
> cppcheck-htmlreport (default is to use the one from the standard path).
> 
> This has been tested on several arm configurations (x86 should work but
> has not been tested).
> 
> [1] https://cppcheck.sourceforge.io/
> 
> Signed-off-by: Bertrand Marquis <bertrand.marquis@xxxxxxx>
> Signed-off-by: Michal Orzel <michal.orzel@xxxxxxx>

Very cool, I was looking forward to this :-)


> diff --git a/xen/tools/merge_cppcheck_reports.py 
> b/xen/tools/merge_cppcheck_reports.py
> new file mode 100755
> index 0000000000..ef055f6925
> --- /dev/null
> +++ b/xen/tools/merge_cppcheck_reports.py
> @@ -0,0 +1,73 @@
> +#!/usr/bin/env python
> +
> +"""
> +This script acts as a tool to merge XML files created by cppcheck.
> +Usage:
> +    merge_cppcheck_reports.py [FILES] [OUTPUT]
> +
> +    FILES  - list of XML files with extension .cppcheck
> +    OUTPUT - file to store results (with .xml extension).
> +             If not specified, the script will print results to stdout.
> +"""
> +
> +import sys
> +from xml.etree import ElementTree
> +
> +def elements_equal(el1, el2):
> +    if type(el1) != type(el2): return False
> +
> +    el1_location = str(el1.find('location').attrib)
> +    el2_location = str(el2.find('location').attrib)
> +
> +    if el1_location != el2_location: return False
> +
> +    return True
> +
> +def remove_duplicates(xml_root_element):
> +    elems_to_remove = []
> +    index = 0
> +    elems_list = list(xml_root_element.findall("errors")[0])
> +    for elem1 in elems_list:
> +        index += 1
> +        for elem2 in elems_list[index:]:
> +            if elements_equal(elem1, elem2) and elem2 not in elems_to_remove:
> +                elems_to_remove.append(elem2)
> +                continue
> +
> +    for elem in elems_to_remove:
> +        xml_root_element.findall("errors")[0].remove(elem)
> +
> +def merge(files):
> +    result_xml_root = None
> +    for xml_file in files:
> +        xml_root = ElementTree.parse(xml_file).getroot()


Traceback (most recent call last):
  File "/local/repos/xen-upstream/xen/tools/merge_cppcheck_reports.py", line 
73, in <module>
    run()
  File "/local/repos/xen-upstream/xen/tools/merge_cppcheck_reports.py", line 
60, in run
    result = merge(files)
  File "/local/repos/xen-upstream/xen/tools/merge_cppcheck_reports.py", line 
43, in merge
    xml_root = ElementTree.parse(xml_file).getroot()
  File "/usr/lib/python2.7/xml/etree/ElementTree.py", line 1182, in parse
    tree.parse(source, parser)
  File "/usr/lib/python2.7/xml/etree/ElementTree.py", line 657, in parse
    self._root = parser.close()
  File "/usr/lib/python2.7/xml/etree/ElementTree.py", line 1671, in close
    self._raiseerror(v)
  File "/usr/lib/python2.7/xml/etree/ElementTree.py", line 1523, in _raiseerror
    raise err
xml.etree.ElementTree.ParseError: no element found: line 11, column 0
make: *** [Makefile:576: xen-cppcheck.xml] Error 1

I think we should catch the xml.etree.ElementTree.ParseError exception and 
continue?