On Tue, 2020-06-30 at 09:51 -0400, David Edelsohn wrote: > The changes to the non-null warning now produce an additional warning > for analyzer/pr94028.C on one of the "leak" lines. This causes new > failures on trunk.
Hi David Do you have the output to hand? What is the full text of the new diagnostic? Some high level questions: * Ought GCC to warn for that code? (or not) * Is it behavior we ought to have a test for? Note that AFAIK there are *two* kinds of non-null warnings that GCC can emit: the kind emitted by Martin's code, versus those emitted by -fanalyzer (the latter imply the much more expensive analysis performed by -fanalyzer, and are controlled by the various -Wanalyzer-*null* options; see https://gcc.gnu.org/onlinedocs/gcc-10.1.0/gcc/Static-Analyzer-Options.html ) > Because non-null is not the purpose of the analyzer test, I propose > pruning the output to resolve the new failures. Looking back through bugzilla, it seems that the main purpose of adding that test was to ensure that -fanalyzer doesn't ICE on that code. At some point I hope to properly support C++ in -fanalyzer, at which point some kind of null warning may be warranted on that code. Sadly I'm not yet at that point. FWIW I'm currently working on a big rewrite of how state is tracked within the analyzer, as I've identified at least two major flaws in the current implementation, which my rewrite addresses. I'm deferring on C++ support until that rewrite is done. > Alternatively, I > could explicitly test for the additional non-null warning. > > Do you have any preferences? This test is controlled by analyzer.exp and thus, for example, is disabled if the analyzer was disabled at configure time. If this is coming from Martin's non-analyzer code, a third possibility would be to use -Wno-something to disable that warning, so that the analyzer test can focus on the -fanalyzer test, as it were (and if this is a behavior that ought to be checked for in Martin's warning, then copy the pertinent fragment of the testcase to one of the g++.dg cases, I suppose). I think I prefer that approach. How does this sound? > I propose appending > > // { dg-prune-output "where non-null expected" } > > to the file to prune the warning output. > > Thanks, David Thanks for looking into this; hope this is constructive. Dave
