llvm dev - Jan 2022 - [EXTERNAL] Re: Responsibilities of a buildbot owner

On 11/01/2022 18:59, Stella Stamenova wrote:
> The windows lldb bot is running on a Hyper-V virtual machine, so it would
make sense that if watchpoints don't work correctly in virtual environments
they would be failing there. On the rare occasion I've had to run these
tests locally, I have also seen them fail though, so that's not the only
source of issues.
> 
> Since I disabled the couple of tests yesterday, there's only one
watchpoint test that is still failing randomly. One option would be to disable
just this test and let the remaining few watchpoint tests continue to run on
Windows (I prefer this option since some tests would continue to run).
Alternatively, all the watchpoint tests can be skipped via the category flag,
but in that case, I'd like us to undo the individual skips.
For better or worse, you're currently the most (only?) interested person 
in keeping windows host support working, so I think you can manage the 
windows skips/fails in any way you see fit. The rest of us are mostly 
interested in having green builds. :)

Hyper-V is _not_ among the virtualization systems I've tried using with 
lldb, so I cannot conclusively say anything about it (though I still 
have my doubts).
> 
> I did notice while going through the watchpoint tests to see what is still
enabled on Windows, that the same watchpoint tests that are disabled/failing on
Windows are disabled on multiple other platforms as well. The tests passing on
Windows are also the ones that are not disabled on other platforms. A third
option would be to add a separate category for the watchpoint tests that
don't run correctly everywhere and use that to disable them instead. This
would be a more generic way to disable the tests instead of adding multiple
`skipIf` statements to each test.
On non-x86 architectures, watchpoints tend to be available only on 
special (developer) hardware or similar (x86 is the outlier in having 
universal support), which is why these tests tend to accumulate various 
annotations. However, I don't think we need to solve this problem (how 
to skip the tests "nicely") here...

pl

Does windows use lldb-server by default or does it use ProcessWindows?
ProcessWindows is the native process debugger, and lldb-server is the way we
want debugging to work. If we look at ProcessWindows.cpp:

static bool ShouldUseLLDBServer() {
  llvm::StringRef use_lldb_server = ::getenv("LLDB_USE_LLDB_SERVER");
  return use_lldb_server.equals_insensitive("on") ||
         use_lldb_server.equals_insensitive("yes") ||
         use_lldb_server.equals_insensitive("1") ||
         use_lldb_server.equals_insensitive("true");
}

void ProcessWindows::Initialize() {
  if (!ShouldUseLLDBServer()) {
    static llvm::once_flag g_once_flag;

    llvm::call_once(g_once_flag, []() {
      PluginManager::RegisterPlugin(GetPluginNameStatic(),
                                    GetPluginDescriptionStatic(),
                                    CreateInstance);
    });
  }
}



We can see it is enabled if LLDB_USE_LLDB_SERVER is set the "on",
"yes", "1", or "true". If this is not set then
this is using the built in ProcessWindows.cpp native process plug-in which I
believe was never fully fleshed out and had issues.

Can someone verify if we are testing with ProcessWindows or lldb-server on the
build bot?

> On Jan 11, 2022, at 10:31 AM, Pavel Labath via llvm-dev <llvm-dev at
lists.llvm.org> wrote:
> 
> On 11/01/2022 18:59, Stella Stamenova wrote:
>> The windows lldb bot is running on a Hyper-V virtual machine, so it
would make sense that if watchpoints don't work correctly in virtual
environments they would be failing there. On the rare occasion I've had to
run these tests locally, I have also seen them fail though, so that's not
the only source of issues.
>> Since I disabled the couple of tests yesterday, there's only one
watchpoint test that is still failing randomly. One option would be to disable
just this test and let the remaining few watchpoint tests continue to run on
Windows (I prefer this option since some tests would continue to run).
Alternatively, all the watchpoint tests can be skipped via the category flag,
but in that case, I'd like us to undo the individual skips.
> 
> For better or worse, you're currently the most (only?) interested
person in keeping windows host support working, so I think you can manage the
windows skips/fails in any way you see fit. The rest of us are mostly interested
in having green builds. :)
> 
> Hyper-V is _not_ among the virtualization systems I've tried using with
lldb, so I cannot conclusively say anything about it (though I still have my
doubts).
> 
>> I did notice while going through the watchpoint tests to see what is
still enabled on Windows, that the same watchpoint tests that are
disabled/failing on Windows are disabled on multiple other platforms as well.
The tests passing on Windows are also the ones that are not disabled on other
platforms. A third option would be to add a separate category for the watchpoint
tests that don't run correctly everywhere and use that to disable them
instead. This would be a more generic way to disable the tests instead of adding
multiple `skipIf` statements to each test.
> 
> On non-x86 architectures, watchpoints tend to be available only on special
(developer) hardware or similar (x86 is the outlier in having universal
support), which is why these tests tend to accumulate various annotations.
However, I don't think we need to solve this problem (how to skip the tests
"nicely") here...
> 
> pl
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