[PATCH] ARM: Do not use FP reg when on AAPCS

[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))