Re: [PING] [PATCH 0/5] Improve support for regcache_map_entry with variable register base

John Baldwin
2022-09-20T17:50:46Z

On 8/22/22 7:11 PM, John Baldwin wrote:
> On 7/21/22 7:53 AM, John Baldwin wrote:
>> On 7/7/22 5:58 PM, John Baldwin wrote:
>>> When I added support for TLS to the ARM and AArch64 architectures on
>>> FreeBSD, I had to construct register maps and associated register sets
>>> on the fly in both the callback for processing register core dump
>>> notes and in the native target routines to fetch and store registers.
>>>
>>> The reason I had to create these on the fly is that the register
>>> number was not known at compile time, so the register map and register
>>> set could not be constant structures shared among the -tdep and -nat
>>> code the way other register sets were.
>>>
>>> This series aims to rectify that. The first patch adds new variants
>>> of regcache::collect_regset and regcache::supply_regset that accept an
>>> additional 'regbase' argument. When these functions iterate over
>>> regcache map entries, the effective register number for the entry is
>>> computed by adding the value in the entry to 'regbase' permittting the
>>> regcache map entries to hold relative register numbers for a block of
>>> registers.
>>>
>>> The rest of the series then makes use of this to use a single, shared
>>> register map and register set for TLS on FreeBSD/ARM and
>>> FreeBSD/AArch64. Using this requires custom supply and collect regset
>>> routines for the TLS regsets that extract the base register number
>>> from the gdbarch's tdep and invoke the new regcache class methods, so
>>> patch 2 updates the wrappers for dealing with regsets in fbsd-nat to
>>> always invoke the regset routines from the regset instead of directly
>>> calling the default functions. Patch 3 is another change to fbsd-nat
>>> to cope with the fact that regcache_map_supplies() needs to pass in
>>> the relative register number in the wrapper routines rather than the
>>> absolute register number.
>>>
>>> Patches 4 and 5 are the updates to the ARM and AArch64 FreeBSD
>>> architectures and targets.
>>>
>>> I have not done the work to make use of this in the Linux AArch64
>>> architecture, though I think it would apply to at least the TLS and
>>> MTE register sets there in a similar fashion. SVE is harder because
>>> the register sizes change (though SVE might be able to make use of
>>> this if register_size() returns the right value by using a register
>>> size of 0 in the relevant register cache map entries).
>>>
>>> John Baldwin (5):
>>> regcache: Add collect/supply_regset variants that accept a register
>>> base.
>>> fbsd-nat: Use regset supply/collect methods.
>>> fbsd-nat: Pass an optional register base to the register set helpers.
>>> arm-fbsd: Use a static regset for the TLS register set.
>>> aarch64-fbsd: Use a static regset for the TLS register set.
>>>
>>> gdb/aarch64-fbsd-nat.c | 36 +++------------------------
>>> gdb/aarch64-fbsd-tdep.c | 54 ++++++++++++++++++++++++++++-------------
>>> gdb/aarch64-fbsd-tdep.h | 1 +
>>> gdb/arm-fbsd-nat.c | 34 +++-----------------------
>>> gdb/arm-fbsd-tdep.c | 52 +++++++++++++++++++++++++++------------
>>> gdb/arm-fbsd-tdep.h | 1 +
>>> gdb/fbsd-nat.c | 42 +++++++++++++++++---------------
>>> gdb/fbsd-nat.h | 49 +++++++++++++++++++++----------------
>>> gdb/regcache.c | 28 ++++++++++++++++++---
>>> gdb/regcache.h | 24 ++++++++++++++++--
>>> 10 files changed, 181 insertions(+), 140 deletions(-)
>>
>> Ping.
>>
>
>

Pinging again. Only patch 1 needs approval by another maintainer, the rest
are FreeBSD specific.

--
John Baldwin