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[PATCH] Minor fix in AVR prologue scan.
- From: Cristiano De Alti <cristiano_dealti at hotmail dot com>
- To: gdb-patches at sourceware dot org
- Cc: Cristiano De Alti <cristiano_dealti at hotmail dot com>
- Date: Thu, 17 Mar 2016 23:41:50 +0100
- Subject: [PATCH] Minor fix in AVR prologue scan.
- Authentication-results: sourceware.org; auth=none
I use GDB from Eclipse with Avarice to debug AVR microcontrollers.
While single stepping (stepi) through the instructions of a normal
function prologue, stepping over the sbiw r28, 0x0f instruction, which
is near the end of the prologue, causes the following change in the
backtrace output:
Before stepi:
#0 0x000042b0 in HID_Device_USBTask (HIDInterfaceInfo=0x80b8b8) at
../../LUFA/Drivers/USB/Class/Device/HIDClassDevice.c:157
#1 0x000002e0 in main () at HIDRadio.c:83
After stepi:
#0 0x000042b2 in HID_Device_USBTask (HIDInterfaceInfo=0x8000ff) at
../../LUFA/Drivers/USB/Class/Device/HIDClassDevice.c:157
#1 0x00017170 in ?? ()
Note that the frame #1 is inconsistent.
If you now return from frame #0 with the finish command, the target does
not stop at the return address at main. Instead, the target starts
running and it's necessary to manually stop it.
This is not a big issue and I'm not an expert of the gdb internals but
the fix seems easy enough.
gdb/ChangeLog:
2016-03-17 Cristiano De Alti <cristiano_dealti@hotmail.com>
* avr-tdep.c (avr_scan_prologue): fix comparison to detect
the prologue limits.
---
gdb/avr-tdep.c | 11 ++++++-----
1 file changed, 6 insertions(+), 5 deletions(-)
diff --git a/gdb/avr-tdep.c b/gdb/avr-tdep.c
index 993e92b..a8080db 100644
--- a/gdb/avr-tdep.c
+++ b/gdb/avr-tdep.c
@@ -833,25 +833,26 @@ avr_scan_prologue (struct gdbarch *gdbarch, CORE_ADDR pc_beg, CORE_ADDR pc_end,
or signal handler functions, which is why we set the prologue type
when we saw the beginning of the prologue previously. */
- if (vpc + sizeof (img_sig) < len
+ if (vpc + sizeof (img_sig) <= len
&& memcmp (prologue + vpc, img_sig, sizeof (img_sig)) == 0)
{
+ info->size += locals_size;
vpc += sizeof (img_sig);
}
- else if (vpc + sizeof (img_int) < len
+ else if (vpc + sizeof (img_int) <= len
&& memcmp (prologue + vpc, img_int, sizeof (img_int)) == 0)
{
+ info->size += locals_size;
vpc += sizeof (img_int);
}
- if (vpc + sizeof (img) < len
+ if (vpc + sizeof (img) <= len
&& memcmp (prologue + vpc, img, sizeof (img)) == 0)
{
+ info->size += locals_size;
info->prologue_type = AVR_PROLOGUE_NORMAL;
vpc += sizeof (img);
}
- info->size += locals_size;
-
/* Fall through. */
}
--
1.7.10.4