[llvm] r272021 - [lit] Improve logging with file redirection.

[Hans Wennborg via llvm-commits]

On Thu, Jun 9, 2016 at 1:36 PM, Hans Wennborg <hans at chromium.org> wrote:
> On Tue, Jun 7, 2016 at 9:13 AM, Daniel Dunbar via llvm-commits
> <llvm-commits at lists.llvm.org> wrote:
>> Author: ddunbar
>> Date: Tue Jun  7 11:13:40 2016
>> New Revision: 272021
>>
>> URL: http://llvm.org/viewvc/llvm-project?rev=272021&view=rev
>> Log:
>> [lit] Improve logging with file redirection.
>>
>>  - This will cause lit to automatically include the first 1K of data in
>>    redirected output files when a command fails (previously if the command
>>    failed, but the main point of the test was, say, a `FileCheck` later on, then
>>    the log wasn't helpful in showing why the command failed).
>
> This makes the test suite hang for me on 32-bit Windows builds. It
> runs fine at r272019, but hangs at this revision (and also on
> ToT/r272292).
>
> I'm not sure how to debug this. It seems after a while, python.exe
> just sits there waiting for something, with 1, 2, or 0 FileCheck
> processes opened.

Maybe it's a problem of running out of file descriptors. I'm not sure
why this is happening on my machine but not on buildbots, though. If I
run lit with -j16, or set NUMBER_OF_PROCESSORS in the environment, the
tests pass, so I'm not blocked on this anymore.