[Lldb-commits] [PATCH] D18978: Support Linux on SystemZ as platform

Ulrich Weigand via lldb-commits lldb-commits at lists.llvm.org
Tue Apr 12 11:33:08 PDT 2016

uweigand added a comment.

In http://reviews.llvm.org/D18978#398180, @labath wrote:

> Could you also add a core file test to `TestLinuxCore`? It should be a matter of running `make_core.sh`, saving the files and creating a new test function in the file (I've tried to make it simple, if you see room for improvement, then let me know).
> I think this is especially important as probably noone here has access to this hardware, so this will enable the rest of the developers to run at least a basic sanity check on their changes.

Yes, that seems to work fine.  I'll add those files with the next update.

> We generally expectedFailure for things which we consider an lldb bug, and skip for cases when the test simply does not apply. Platform not having enough watchpoints sounds like the latter case. I see you were simply copying the mips case (which does not follow this either), and it doesn't really matter to me, but I just wanted to make you aware of that.

So I guess my thought was that in theory, there may be ways to support multiple watchpoints.  In particular, while the hardware only supports a single watchpoint, this may span an address range of arbitrary length.  So it may be possible to implement two or more watchpoints by registering a watchpoint range with the hardware that spans all the areas that need to be watched.  However, when the hardware then reports a watchpoint hit, we'd have to find out which of the original watchpoints is affected, and ignore cases where we get false positives due to hits elsewhere in the range.  This is in fact implemented in GDB, so it should be possible.  But an LLDB implementation of this idea seems a bit more complex, and certainly not something I wanted to include in the initial submission ...


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