* [PATCH] ARM: Do not use FP reg when on AAPCS
@ 2018-10-23 13:03 Marius Muench
2018-10-23 17:16 ` Kevin Buettner
0 siblings, 1 reply; 9+ messages in thread
From: Marius Muench @ 2018-10-23 13:03 UTC (permalink / raw)
To: gdb-patches
Hi all,
GDB tries to dereference the frame pointer in arm_scan_prologue as a
last resort to create frame information.
However, the more recent AAPCS ABI does not make use of a frame pointer.
This patch checks whether the specified arm_abi is AAPCS before
dereferencing the "frame pointer". If so, just return as efforts to use
it for restoring frame information won't work.
Cheers,
Marius
gdb/ChangeLog
2018-10-23 Marius Muench <marius.muench@eurecom.fr>
* arm-tdeb.c (arm_scan_prologue): Don't dereference FP reg
when on aapcs.
---
gdb/arm-tdep.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/gdb/arm-tdep.c b/gdb/arm-tdep.c
index 53eee76926..859ce71d6a 100644
--- a/gdb/arm-tdep.c
+++ b/gdb/arm-tdep.c
@@ -1801,6 +1801,10 @@ arm_scan_prologue (struct frame_info *this_frame,
CORE_ADDR frame_loc;
ULONGEST return_value;
+ /* AAPCS does not use a frame register, so we can abort here. */
+ if (gdbarch_tdep (gdbarch)->arm_abi == ARM_ABI_AAPCS)
+ return;
+
frame_loc = get_frame_register_unsigned (this_frame, ARM_FP_REGNUM);
if (!safe_read_memory_unsigned_integer (frame_loc, 4, byte_order,
&return_value))
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH] ARM: Do not use FP reg when on AAPCS
2018-10-23 13:03 [PATCH] ARM: Do not use FP reg when on AAPCS Marius Muench
@ 2018-10-23 17:16 ` Kevin Buettner
2018-10-24 11:40 ` Marius Muench
0 siblings, 1 reply; 9+ messages in thread
From: Kevin Buettner @ 2018-10-23 17:16 UTC (permalink / raw)
To: gdb-patches; +Cc: Marius Muench
On Tue, 23 Oct 2018 15:03:39 +0200
Marius Muench <munch@eurecom.fr> wrote:
> Hi all,
>
> GDB tries to dereference the frame pointer in arm_scan_prologue as a
> last resort to create frame information.
> However, the more recent AAPCS ABI does not make use of a frame pointer.
>
> This patch checks whether the specified arm_abi is AAPCS before
> dereferencing the "frame pointer". If so, just return as efforts to use
> it for restoring frame information won't work.
>
> Cheers,
> Marius
>
> gdb/ChangeLog
> 2018-10-23 Marius Muench <marius.muench@eurecom.fr>
>
> * arm-tdeb.c (arm_scan_prologue): Don't dereference FP reg
> when on aapcs.
Typo on filename above. (s/tdeb/tdep/) While you're changing it,
please capitalize AAPCS too.
Otherwise, okay.
Kevin
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH] ARM: Do not use FP reg when on AAPCS
2018-10-23 17:16 ` Kevin Buettner
@ 2018-10-24 11:40 ` Marius Muench
2018-10-24 16:47 ` Kevin Buettner
2018-10-24 17:23 ` Pedro Alves
0 siblings, 2 replies; 9+ messages in thread
From: Marius Muench @ 2018-10-24 11:40 UTC (permalink / raw)
To: Kevin Buettner, gdb-patches; +Cc: Marius Muench
On 10/23/18 7:16 PM, Kevin Buettner wrote:
> On Tue, 23 Oct 2018 15:03:39 +0200
> Marius Muench <munch@eurecom.fr> wrote:
>> gdb/ChangeLog
>> 2018-10-23 Marius Muench <marius.muench@eurecom.fr>
>>
>> * arm-tdeb.c (arm_scan_prologue): Don't dereference FP reg
>> when on aapcs.
>
> Typo on filename above. (s/tdeb/tdep/) While you're changing it,
> please capitalize AAPCS too.
>
> Otherwise, okay.
>
> Kevin
>
Good catch, sorry for that. Here's the updated patch.
Thanks,
Marius
2018-10-24 Marius Muench <marius.muench@eurecom.fr>
* arm-tdep.c (arm_scan_prologue): Don't dereference FP reg
when on AAPCS.
---
gdb/arm-tdep.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/gdb/arm-tdep.c b/gdb/arm-tdep.c
index 53eee76926..5cff22977d 100644
--- a/gdb/arm-tdep.c
+++ b/gdb/arm-tdep.c
@@ -1801,6 +1801,10 @@ arm_scan_prologue (struct frame_info *this_frame,
CORE_ADDR frame_loc;
ULONGEST return_value;
+ /* AAPCS does not use a frame register, so we can abort here. */
+ if (gdbarch_tdep (gdbarch)->arm_abi == ARM_ABI_AAPCS)
+ return;
+
frame_loc = get_frame_register_unsigned (this_frame, ARM_FP_REGNUM);
if (!safe_read_memory_unsigned_integer (frame_loc, 4, byte_order,
&return_value))
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH] ARM: Do not use FP reg when on AAPCS
2018-10-24 11:40 ` Marius Muench
@ 2018-10-24 16:47 ` Kevin Buettner
2018-10-24 17:23 ` Pedro Alves
1 sibling, 0 replies; 9+ messages in thread
From: Kevin Buettner @ 2018-10-24 16:47 UTC (permalink / raw)
To: Marius Muench; +Cc: gdb-patches, Marius Muench
> 2018-10-24 Marius Muench <marius.muench@eurecom.fr>
>
> * arm-tdep.c (arm_scan_prologue): Don't dereference FP reg
> when on AAPCS.
Okay.
Kevin
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH] ARM: Do not use FP reg when on AAPCS
2018-10-24 11:40 ` Marius Muench
2018-10-24 16:47 ` Kevin Buettner
@ 2018-10-24 17:23 ` Pedro Alves
2018-10-24 19:37 ` Marius Muench
1 sibling, 1 reply; 9+ messages in thread
From: Pedro Alves @ 2018-10-24 17:23 UTC (permalink / raw)
To: Marius Muench, Kevin Buettner, gdb-patches; +Cc: Marius Muench
Tiny nit:
On 10/24/2018 12:40 PM, Marius Muench wrote:
>
> + /* AAPCS does not use a frame register, so we can abort here. */
There should be a double space after the period.
> + if (gdbarch_tdep (gdbarch)->arm_abi == ARM_ABI_AAPCS)
> + return;
Thanks,
Pedro Alves
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH] ARM: Do not use FP reg when on AAPCS
2018-10-24 17:23 ` Pedro Alves
@ 2018-10-24 19:37 ` Marius Muench
2018-10-25 20:34 ` Kevin Buettner
0 siblings, 1 reply; 9+ messages in thread
From: Marius Muench @ 2018-10-24 19:37 UTC (permalink / raw)
To: Pedro Alves, Kevin Buettner, gdb-patches
On 10/24/2018 07:23 PM, Pedro Alves wrote:
> Tiny nit:
>
> On 10/24/2018 12:40 PM, Marius Muench wrote:
>>
>> + /* AAPCS does not use a frame register, so we can abort here. */
>
> There should be a double space after the period.
>
>> + if (gdbarch_tdep (gdbarch)->arm_abi == ARM_ABI_AAPCS)
>> + return;
>
> Thanks,
> Pedro Alves
>
Fair enough, updated version below.
gdb/ChangeLog:
2018-10-24 Marius Muench <marius.muench@eurecom.fr>
* arm-tdep.c (arm_scan_prologue): Don't dereference FP reg
when on AAPCS.
---
gdb/arm-tdep.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/gdb/arm-tdep.c b/gdb/arm-tdep.c
index 53eee76926..0165e92527 100644
--- a/gdb/arm-tdep.c
+++ b/gdb/arm-tdep.c
@@ -1801,6 +1801,10 @@ arm_scan_prologue (struct frame_info *this_frame,
CORE_ADDR frame_loc;
ULONGEST return_value;
+ /* AAPCS does not use a frame register, so we can abort here. */
+ if (gdbarch_tdep (gdbarch)->arm_abi == ARM_ABI_AAPCS)
+ return;
+
frame_loc = get_frame_register_unsigned (this_frame, ARM_FP_REGNUM);
if (!safe_read_memory_unsigned_integer (frame_loc, 4, byte_order,
&return_value))
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH] ARM: Do not use FP reg when on AAPCS
2018-10-24 19:37 ` Marius Muench
@ 2018-10-25 20:34 ` Kevin Buettner
2018-10-26 12:13 ` Marius Muench
0 siblings, 1 reply; 9+ messages in thread
From: Kevin Buettner @ 2018-10-25 20:34 UTC (permalink / raw)
To: gdb-patches; +Cc: Marius Muench, Pedro Alves
On Wed, 24 Oct 2018 21:37:07 +0200
Marius Muench <marius.muench@eurecom.fr> wrote:
> Fair enough, updated version below.
>
> gdb/ChangeLog:
> 2018-10-24 Marius Muench <marius.muench@eurecom.fr>
>
> * arm-tdep.c (arm_scan_prologue): Don't dereference FP reg
> when on AAPCS.
Looks good to me.
You can commit / push this now...
Kevin
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH] ARM: Do not use FP reg when on AAPCS
2018-10-25 20:34 ` Kevin Buettner
@ 2018-10-26 12:13 ` Marius Muench
2018-11-06 17:53 ` Tom Tromey
0 siblings, 1 reply; 9+ messages in thread
From: Marius Muench @ 2018-10-26 12:13 UTC (permalink / raw)
To: Kevin Buettner, gdb-patches; +Cc: Marius Muench, Pedro Alves
Thanks! I don't have push permissions, as it is my first contribution to
this project.
I can't find any documentation what to do in this case, scraping the ML,
I see three possible strategies:
(1) One of you push on my behalf.
(2) I send a new (clean) version of this patch, which gets pushed on my
behalf.
(3) Push permissions are set up.
What's your preferred strategy here?
Thanks a lot,
Marius
On 10/25/18 10:34 PM, Kevin Buettner wrote:
> On Wed, 24 Oct 2018 21:37:07 +0200
> Marius Muench <marius.muench@eurecom.fr> wrote:
>
>> Fair enough, updated version below.
>>
>> gdb/ChangeLog:
>> 2018-10-24 Marius Muench <marius.muench@eurecom.fr>
>>
>> * arm-tdep.c (arm_scan_prologue): Don't dereference FP reg
>> when on AAPCS.
>
> Looks good to me.
>
> You can commit / push this now...
>
> Kevin
>
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH] ARM: Do not use FP reg when on AAPCS
2018-10-26 12:13 ` Marius Muench
@ 2018-11-06 17:53 ` Tom Tromey
0 siblings, 0 replies; 9+ messages in thread
From: Tom Tromey @ 2018-11-06 17:53 UTC (permalink / raw)
To: Marius Muench; +Cc: Kevin Buettner, gdb-patches, Marius Muench, Pedro Alves
>>>>> "Marius" == Marius Muench <munch@eurecom.fr> writes:
Marius> Thanks! I don't have push permissions, as it is my first contribution to
Marius> this project.
Marius> I can't find any documentation what to do in this case, scraping the ML,
Marius> I see three possible strategies:
Marius> (1) One of you push on my behalf.
Sorry about the delay on this.
I am pushing it now.
Marius> (2) I send a new (clean) version of this patch, which gets pushed on my
Marius> behalf.
Marius> (3) Push permissions are set up.
If you plan to do more work on gdb, you should consider getting
write-after-approval access. I think copyright paperwork is needed
first though.
Tom
^ permalink raw reply [flat|nested] 9+ messages in thread
end of thread, other threads:[~2018-11-06 17:53 UTC | newest]
Thread overview: 9+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2018-10-23 13:03 [PATCH] ARM: Do not use FP reg when on AAPCS Marius Muench
2018-10-23 17:16 ` Kevin Buettner
2018-10-24 11:40 ` Marius Muench
2018-10-24 16:47 ` Kevin Buettner
2018-10-24 17:23 ` Pedro Alves
2018-10-24 19:37 ` Marius Muench
2018-10-25 20:34 ` Kevin Buettner
2018-10-26 12:13 ` Marius Muench
2018-11-06 17:53 ` Tom Tromey
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