On Wed, 2017-07-26 at 18:00 +0200, Pierre-Marie de Rodat wrote: > Hello, > > At the last GNU Cauldron, Richard Biener and I talked about DWARF > output > testing. Except for guality tests, which are disabled on several > targets, the only way tests check the DWARF is scanning the annotated > assembly (-dA), making it hard to write reliable tests. > > For instance, checking the number of times DW_AT_location is present > in > order to check that some specific variable is assigned one is fuzzy. > Depending on the target and on the evolution of the compiler, the > number > of output variables, or which one is assigned a location can vary > legitimately but still make the test fail. > > On my side, I already had written an out-of-tree testsuite for the > DWARF > features I added for Ada. This testsuite uses a DWARF parser in order > to > perform checks on a tree: > <https://github.com/pmderodat/dwarf-ada-testsuite/>. I had to update > it > a couple of times, for instance when a change created a > DW_TAG_const_type DIE or removed one somewhere in a type tree, but > that’s very rare. I would say that I’m satisfied with the checks I > could > express, but I don’t remember I ever caught a regression with them, > so I > have no representative experience to share in this area. Maybe DWARF > back-end developpers do a too good job. ;-) > > Anyway, Richard and I discussed about doing something similar in > -tree, > and here is a candidate set of patches to achieve that: > > * The first patch installs DejaGNU scripts to run a Python > interpreter > in testcases. > > * The second one installs other DejaGNU scripts to detect DWARF > dumping tools, plus a small Python library to parse and pattern > match DIEs and their attributes. It also adds several C and Ada > tests as examples; these are inspired by existing homonym tests > based on assembly scanning. > > For now, this supports only platforms where objdump is available for > the > current target, but extending it to other tools, such as otool on > Darwin > should be doable. > > I would appreciate feedback about the idea and the implementation I > propose. This is the first time I do more in the testsuite than just > adding new tests, so thank you in advance for you patience in > reviewing > these. :-)
(FWIW I'm a big fan of Python, so am happy to see this proposal) > I tested these patches on x86_64-linux. Which version of Python did you test against? As far as I can see you've coded this using the common subset of Python 2 and Python 3; it's worth spelling out what the assumptions are in this regard (and what the minimum versions are). Dave
