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Re: [PATCH] MIPS: Add option to pass return address location to _mcount.
- From: Wu Zhangjin <wuzhangjin at gmail dot com>
- To: Richard Sandiford <rdsandiford at googlemail dot com>
- Cc: David Daney <ddaney at caviumnetworks dot com>, GCC Patches <gcc-patches at gcc dot gnu dot org>, linux-mips at linux-mips dot org, Adam Nemet <anemet at caviumnetworks dot com>, rostedt at goodmis dot org, Thomas Gleixner <tglx at linutronix dot de>, Ralf Baechle <ralf at linux-mips dot org>, Nicholas Mc Guire <der dot herr at hofr dot at>
- Date: Thu, 29 Oct 2009 14:44:34 +0800
- Subject: Re: [PATCH] MIPS: Add option to pass return address location to _mcount.
- References: <028867b99ec532b84963a35e7d552becc783cafc.1256135456.git.wuzhangjin@gmail.com> <2f73eae542c47ac5bbb9f7280e6c0271d193e90d.1256135456.git.wuzhangjin@gmail.com> <3f0d3515f74a58f4cfd11e61b62a129fdc21e3a7.1256135456.git.wuzhangjin@gmail.com> <ea8aa927fbd184b54941e4c2ae0be8ea0b4f6b8a.1256135456.git.wuzhangjin@gmail.com> <1256138686.18347.3039.camel@gandalf.stny.rr.com> <1256233679.23653.7.camel@falcon> <4AE0A5BE.8000601@caviumnetworks.com> <87y6n36plp.fsf@firetop.home> <4AE232AD.4050308@caviumnetworks.com> <87my3htau1.fsf@firetop.home> <4AE5F392.5020405@caviumnetworks.com> <87ljiwr0t9.fsf@firetop.home>
- Reply-to: wuzhangjin at gmail dot com
Hi,
On Tue, 2009-10-27 at 21:20 +0000, Richard Sandiford wrote:
[...]
> OK with those changes,
Just applied the above changes, and added one more for not getting the
ra_fp_offset when -pg is not enabled:
@@ -9619,6 +9622,9 @@ mips_for_each_saved_gpr_and_fpr (HOST_WIDE_INT
sp_offset,
for (regno = GP_REG_LAST; regno >= GP_REG_FIRST; regno--)
if (BITSET_P (cfun->machine->frame.mask, regno - GP_REG_FIRST))
{
+ /* Record the ra offset for use by mips_function_profiler. */
+ if (crtl->profile && regno == RETURN_ADDR_REGNUM)
+ cfun->machine->frame.ra_fp_offset = offset + sp_offset;
mips_save_restore_reg (word_mode, regno, offset, fn);
offset -= UNITS_PER_WORD;
}
"crtl->profile &&" was added.
> thanks, if it passing testing, and if
> Ralf is happy with the linux side.
>
Just appended that patch with the above changes to the latest gcc 4.5 in
the git repository, and tested it, which works well.
this is the result of a non-leaf function:
ffffffff80243c08 <copy_process>:
ffffffff80243c08: 67bdff40 daddiu sp,sp,-192
ffffffff80243c0c: ffbe00b0 sd s8,176(sp)
ffffffff80243c10: 03a0f02d move s8,sp
ffffffff80243c14: ffbf00b8 sd ra,184(sp)
[...]
ffffffff80243c38: 3c038021 lui v1,0x8021
ffffffff80243c3c: 64631530 daddiu v1,v1,5424
ffffffff80243c40: 03e0082d move at,ra
ffffffff80243c44: 0060f809 jalr v1
ffffffff80243c48: 67ac00b8 daddiu t0,sp,184 --> Here it is
and for a leaf function:
ffffffff802054d0 <au1k_wait>:
ffffffff802054d0: 67bdfff0 daddiu sp,sp,-16
ffffffff802054d4: ffbe0008 sd s8,8(sp)
ffffffff802054d8: 03a0f02d move s8,sp
ffffffff802054dc: 3c038021 lui v1,0x8021
ffffffff802054e0: 64631530 daddiu v1,v1,5424
ffffffff802054e4: 03e0082d move at,ra
ffffffff802054e8: 0060f809 jalr v1
ffffffff802054ec: 0000602d move t0,zero --> Here it is
and with this new feature, I can safely remove the old
ftrace_get_parent_addr() and add several more instructions to make
function graph tracer work. and also, 'Cause this feature used the
t0($12) register, I must change the temp registers I have used in the
patches of ftrace for MIPS(t0 --> t1, t1 --> t2, t2-> t3...). no more
touch.
The latest revision of this patch will be sent out in the next E-mail,
and also, the -v8 revision of ftrace for MIPS will be sent out with this
new feature of Gcc asap.
Thanks & Regards,
Wu Zhangjin