* [PATCH] gdb: mips: Fix large-frame.exp test case failure
@ 2022-03-15 1:21 Youling Tang
2022-03-16 16:40 ` Tom Tromey
0 siblings, 1 reply; 5+ messages in thread
From: Youling Tang @ 2022-03-15 1:21 UTC (permalink / raw)
To: gdb-patches, Maciej W. Rozycki
$ objdump -d outputs/gdb.base/large-frame/large-frame-O2
0000000120000b20 <func>:
120000b20: 67bdbff0 daddiu sp,sp,-16400
120000b24: ffbc4000 sd gp,16384(sp)
120000b28: 3c1c0002 lui gp,0x2
120000b2c: 679c8210 daddiu gp,gp,-32240
120000b30: 0399e02d daddu gp,gp,t9
120000b34: df998058 ld t9,-32680(gp)
120000b38: ffbf4008 sd ra,16392(sp)
120000b3c: 0411ffd8 bal 120000aa0 <blah>
...
The disassembly of the above func function shows that we may use instructions
such as daddiu/daddu, so add "daddiu $gp,$gp,n", "daddu $gp,$gp,$t9" and
"daddu $gp,$t9,$gp" to the mips32_scan_prologue function to fix the large-frame.exp
test case.
Before applying the patch:
backtrace^M
#0 blah (a=0xfffffee220) at /home/tang/gdb-work/upstream/binutils-gdb/gdb/testsuite/gdb.base/large-frame-1.c:24^M
#1 0x0000000120000b44 in func ()^M
Backtrace stopped: frame did not save the PC^M
(gdb) FAIL: gdb.base/large-frame.exp: optimize=-O2: backtrace
# of expected passes 5
# of unexpected failures 1
After applying the patch:
# of expected passes 6
Signed-off-by: Youling Tang <tangyouling@loongson.cn>
---
gdb/mips-tdep.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/gdb/mips-tdep.c b/gdb/mips-tdep.c
index 5cd72ae..7e37578 100644
--- a/gdb/mips-tdep.c
+++ b/gdb/mips-tdep.c
@@ -3588,8 +3588,11 @@ mips32_scan_prologue (struct gdbarch *gdbarch,
|| (inst & 0xFF9F07FF) == 0x00800021 /* move reg,$a0-$a3 */
|| high_word == 0x3c1c /* lui $gp,n */
|| high_word == 0x279c /* addiu $gp,$gp,n */
+ || high_word == 0x679c /* daddiu $gp,$gp,n */
|| inst == 0x0399e021 /* addu $gp,$gp,$t9 */
|| inst == 0x033ce021 /* addu $gp,$t9,$gp */
+ || inst == 0x0399e02d /* daddu $gp,$gp,$t9 */
+ || inst == 0x033ce02d /* daddu $gp,$t9,$gp */
)
{
/* These instructions are part of the prologue, but we don't
--
2.1.0
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] gdb: mips: Fix large-frame.exp test case failure
2022-03-15 1:21 [PATCH] gdb: mips: Fix large-frame.exp test case failure Youling Tang
@ 2022-03-16 16:40 ` Tom Tromey
2022-03-16 18:36 ` Maciej W. Rozycki
0 siblings, 1 reply; 5+ messages in thread
From: Tom Tromey @ 2022-03-16 16:40 UTC (permalink / raw)
To: Youling Tang; +Cc: gdb-patches, Maciej W. Rozycki
Hi. Thank you for the patch.
>> The disassembly of the above func function shows that we may use instructions
>> such as daddiu/daddu, so add "daddiu $gp,$gp,n", "daddu $gp,$gp,$t9" and
>> "daddu $gp,$t9,$gp" to the mips32_scan_prologue function to fix the large-frame.exp
>> test case.
Since I don't know the MIPS architecture, my main question for this kind
of patch is whether this applies to the whole MIPS family, or whether it
somehow depends on some micro-architecture.
If it applies universally, or if it can't hurt other forms of MIPS, then
the patch itself looks good to me and you can go ahead.
thanks,
Tom
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] gdb: mips: Fix large-frame.exp test case failure
2022-03-16 16:40 ` Tom Tromey
@ 2022-03-16 18:36 ` Maciej W. Rozycki
2022-03-16 20:30 ` Tom Tromey
0 siblings, 1 reply; 5+ messages in thread
From: Maciej W. Rozycki @ 2022-03-16 18:36 UTC (permalink / raw)
To: Tom Tromey; +Cc: Youling Tang, gdb-patches
On Wed, 16 Mar 2022, Tom Tromey wrote:
> >> The disassembly of the above func function shows that we may use instructions
> >> such as daddiu/daddu, so add "daddiu $gp,$gp,n", "daddu $gp,$gp,$t9" and
> >> "daddu $gp,$t9,$gp" to the mips32_scan_prologue function to fix the large-frame.exp
> >> test case.
>
> Since I don't know the MIPS architecture, my main question for this kind
> of patch is whether this applies to the whole MIPS family, or whether it
> somehow depends on some micro-architecture.
It is a standard code sequence for loading the GP with the n64 ABI (I
don't know why DADDIU rather than ADDIU has been chosen for the low part
of the 32-bit offset given that they produce the same result, but there
you go), produced either explicitly by GCC or by GAS with the `.cpsetup'
assembly pseudo-op (in which case ADDIU is actually used).
Maciej
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] gdb: mips: Fix large-frame.exp test case failure
2022-03-16 18:36 ` Maciej W. Rozycki
@ 2022-03-16 20:30 ` Tom Tromey
2022-05-10 21:13 ` Maciej W. Rozycki
0 siblings, 1 reply; 5+ messages in thread
From: Tom Tromey @ 2022-03-16 20:30 UTC (permalink / raw)
To: Maciej W. Rozycki; +Cc: Tom Tromey, Youling Tang, gdb-patches
Maciej> It is a standard code sequence for loading the GP with the n64 ABI (I
Maciej> don't know why DADDIU rather than ADDIU has been chosen for the low part
Maciej> of the 32-bit offset given that they produce the same result, but there
Maciej> you go), produced either explicitly by GCC or by GAS with the `.cpsetup'
Maciej> assembly pseudo-op (in which case ADDIU is actually used).
Thanks! If you're still looking at MIPS patches I will just let them
slide by :-)
Tom
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] gdb: mips: Fix large-frame.exp test case failure
2022-03-16 20:30 ` Tom Tromey
@ 2022-05-10 21:13 ` Maciej W. Rozycki
0 siblings, 0 replies; 5+ messages in thread
From: Maciej W. Rozycki @ 2022-05-10 21:13 UTC (permalink / raw)
To: Tom Tromey; +Cc: Youling Tang, gdb-patches
On Wed, 16 Mar 2022, Tom Tromey wrote:
> Maciej> It is a standard code sequence for loading the GP with the n64 ABI (I
> Maciej> don't know why DADDIU rather than ADDIU has been chosen for the low part
> Maciej> of the 32-bit offset given that they produce the same result, but there
> Maciej> you go), produced either explicitly by GCC or by GAS with the `.cpsetup'
> Maciej> assembly pseudo-op (in which case ADDIU is actually used).
>
> Thanks! If you're still looking at MIPS patches I will just let them
> slide by :-)
I thought this change had been pushed, and then I've noticed it has not.
I have therefore verified the microMIPS prologue scanner already has the
corresponding bits, reformatted the change description so as to make it
fit in 74 columns, added a couple of line breaks, removed `^M' artifacts,
and finally pushed the commit.
Thank you, Youling, for your contribution!
Maciej
^ permalink raw reply [flat|nested] 5+ messages in thread
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2022-03-15 1:21 [PATCH] gdb: mips: Fix large-frame.exp test case failure Youling Tang
2022-03-16 16:40 ` Tom Tromey
2022-03-16 18:36 ` Maciej W. Rozycki
2022-03-16 20:30 ` Tom Tromey
2022-05-10 21:13 ` Maciej W. Rozycki
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