Re: [PATCH v4 2/2] LAM: Enable tagged pointer support for watchpoints.

[Eli Zaretskii <eliz@gnu.org>]

> From: "Schimpe, Christina" <christina.schimpe@intel.com>
> CC: "gdb-patches@sourceware.org" <gdb-patches@sourceware.org>, "Willgerodt,
>  Felix" <felix.willgerodt@intel.com>, "luis.machado@arm.com"
> 	<luis.machado@arm.com>
> Date: Fri, 5 Jul 2024 08:53:29 +0000
> 
> > > From: "Schimpe, Christina" <christina.schimpe@intel.com>
> > > CC: "gdb-patches@sourceware.org" <gdb-patches@sourceware.org>,
> > > "Willgerodt,  Felix" <felix.willgerodt@intel.com>, "luis.machado@arm.com"
> > > 	<luis.machado@arm.com>
> > > Date: Thu, 4 Jul 2024 13:15:20 +0000
> > >
> > > So to answer your question properly: No, we don't explain the term "
> > tagged data pointers" anywhere.
> > > But we write for instance in the commit message "tagged pointers used
> > > for data accesses", which is understandable I think.
> > 
> > Well, I'm sorry to say that it doesn't explain this enough for me.
> > I'm quite a heavy user of GDB, but I have no idea what is a tagged pointer for
> > data access.  Do we have in the manual anything related to such pointers,
> > even if we use different words to talk about them?  If so, could you point me
> > to those descriptions in the manual?  Maybe if I read what we say there, I
> > could suggest wording for NEWS that will be consistent with our terminology
> > in the manual.
> > 
> > Thanks.
> 
> Hi Eli, 
> 
> Sorry for the confusion here.
> You are right, the term "tagged pointer" is not explained anywhere in the manual. 
> Also I couldn't find a section that describes them but uses a different wording.
> 
> I think the first time we use this term in GDB is with commit
> "Clear non-significant bits of address on memory access".  
> The terms tagged address and tagged pointer are used.
> 
> A very similar commit for setting a  watchpoint on a tagged address but for AArch64 is:
> "Clear non-significant bits of address in watchpoint"
> 
> For both commits I couldn't find any documentation/NEWS part.
> 
> I will try to come up with a section on tagged addresses/pointers in the manual.

Thank you.