[RFA/mips(commit?)] Unwinding from noreturn function
Joel Brobecker
brobecker@adacore.com
Wed Mar 7 21:42:00 GMT 2007
> I Am Dumb. Check CVS history, but I think I changed that just a
> couple of weeks ago; I audited all the sniffers looking for what ought
> to use the unwound PC and what ought to use the unwound block address.
> Here, I'm pretty sure I made the wrong choice.
Yep, I remembered. However, I also thought that your choice made sense.
I really think it does, but given:
> I would recommend you revert my changes to this function and
> mips_insn32_frame_sniffer instead.
And:
> > It seems to me that the above check is only an optimization,
> > and I've spotted at least one instance where I cannot see an
> > obvious guaranty that the address has not been decremented
> > by one of the _in_block functions... So the decision I made
> > was to remove that check.
>
> No, it's not just an optimization. Especially with limited debug
> info, it's important.
^^^^^^^^^^^^^^
I decided to revert your changes for now.
> > 2. One minor: There was a confusion in the unwinder between
> > the return address and the address of the instruction calling us.
> > So I replaced frame_pc_unwind calls by their associated
> > frame_unwind_address_in_block.
>
> This half looks right.
Thanks.
So here is what I ended up checkin in:
2007-03-07 Joel Brobecker <brobecker@adacore.com>
* mips-tdep.c (mips_insn16_frame_cache, mips_insn32_frame_sniffer):
Revert the previous change that had some unexpected side-effects
on mips32.
(mips_insn16_frame_cache, mips_insn32_frame_cache): Use the proper
function to get the address of the calling instruction.
Re-tested on mips-irix, just to be sure. Same results as before
(meaning about 500 less FAILs).
I'm also sad to report that I have been told to put off work on
mips-irix for a while. That was a personal initiative on my side,
but I'm lacking time at work, so this was the first task that got cut.
I hope someone else can find the time to bring it back to life...
Thanks again, Daniel.
--
Joel
-------------- next part --------------
Index: mips-tdep.c
===================================================================
RCS file: /cvs/src/src/gdb/mips-tdep.c,v
retrieving revision 1.404
diff -u -p -r1.404 mips-tdep.c
--- mips-tdep.c 27 Feb 2007 20:17:19 -0000 1.404
+++ mips-tdep.c 7 Mar 2007 21:26:32 -0000
@@ -1640,7 +1640,8 @@ mips_insn16_frame_cache (struct frame_in
/* Analyze the function prologue. */
{
- const CORE_ADDR pc = frame_pc_unwind (next_frame);
+ const CORE_ADDR pc =
+ frame_unwind_address_in_block (next_frame, NORMAL_FRAME);
CORE_ADDR start_addr;
find_pc_partial_function (pc, NULL, &start_addr, NULL);
@@ -1693,7 +1694,7 @@ static const struct frame_unwind mips_in
static const struct frame_unwind *
mips_insn16_frame_sniffer (struct frame_info *next_frame)
{
- CORE_ADDR pc = frame_unwind_address_in_block (next_frame, NORMAL_FRAME);
+ CORE_ADDR pc = frame_pc_unwind (next_frame);
if (mips_pc_is_mips16 (pc))
return &mips_insn16_frame_unwind;
return NULL;
@@ -1961,7 +1962,8 @@ mips_insn32_frame_cache (struct frame_in
/* Analyze the function prologue. */
{
- const CORE_ADDR pc = frame_pc_unwind (next_frame);
+ const CORE_ADDR pc =
+ frame_unwind_address_in_block (next_frame, NORMAL_FRAME);
CORE_ADDR start_addr;
find_pc_partial_function (pc, NULL, &start_addr, NULL);
@@ -2014,7 +2016,7 @@ static const struct frame_unwind mips_in
static const struct frame_unwind *
mips_insn32_frame_sniffer (struct frame_info *next_frame)
{
- CORE_ADDR pc = frame_unwind_address_in_block (next_frame, NORMAL_FRAME);
+ CORE_ADDR pc = frame_pc_unwind (next_frame);
if (! mips_pc_is_mips16 (pc))
return &mips_insn32_frame_unwind;
return NULL;
More information about the Gdb-patches
mailing list