From mboxrd@z Thu Jan  1 00:00:00 1970
From: Helge Deller <deller@gmx.de>
Subject: Re: Out of order unwind entry warning
Date: Wed, 28 Oct 2009 23:59:47 +0100
Message-ID: <4AE8CCE3.1030503@gmx.de>
References: <20091028221827.1B7774E38@hiauly1.hia.nrc.ca> <4AE8C918.8060908@gmx.de>
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Cc: linux-parisc@vger.kernel.org, carlos@systemhalted.org,
	randolph@tausq.org
To: John David Anglin <dave@hiauly1.hia.nrc.ca>
Return-path: <linux-parisc-owner@vger.kernel.org>
In-Reply-To: <4AE8C918.8060908@gmx.de>
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On 10/28/2009 11:43 PM, Helge Deller wrote:
> On 10/28/2009 11:18 PM, John David Anglin wrote:
>>>> and whether it follows inb in its .o. From my understanding of things,
>>>> it shouldn't be necessary to remove the unwind info for unused weak
>>>> symbols if they aren't garbage collected. A simple testcase would
>>>> be helpful.

Attached is a testcase (t1.c and t2.c):
t1.c contains weak function f().
t2.c contains non-weak function f().

hppa-linux-gcc -c t1.c t2.c
hppa-linux-ld -r -o all.o t1.o t2.o

hppa-linux-readelf -s t1.o gives:
Symbol table '.symtab' contains 10 entries:
    Num:    Value  Size Type    Bind   Vis      Ndx Name
      6: 00000000    28 FUNC    GLOBAL DEFAULT    1 a
      7: 0000001c    32 FUNC    WEAK   DEFAULT    1 f
      8: 0000003c    28 FUNC    GLOBAL DEFAULT    1 z
      9: 00000058    80 FUNC    GLOBAL DEFAULT    1 main

hppa-linux-readelf -s t2.o  gives:
Symbol table '.symtab' contains 7 entries:
    Num:    Value  Size Type    Bind   Vis      Ndx Name
      6: 00000000    32 FUNC    GLOBAL DEFAULT    1 f

hppa-linux-readelf -s all.o  gives:
Symbol table '.symtab' contains 11 entries:
    Num:    Value  Size Type    Bind   Vis      Ndx Name
      7: 00000000    32 FUNC    GLOBAL DEFAULT    3 f
      8: 0000003c    28 FUNC    GLOBAL DEFAULT    1 z
      9: 00000058    80 FUNC    GLOBAL DEFAULT    1 main
     10: 00000000    28 FUNC    GLOBAL DEFAULT    1 a


hppa-linux-readelf -u all.o  gives:
Unwind section '.PARISC.unwind' at offset 0xfc contains 5 entries:
<a>: [0x0-0x30]
         Entry_GR=1 Save_SP Total_frame_size=8
<f>: [0x0-0x70]
         Entry_GR=1 Save_SP Total_frame_size=8
<z>: [0x3c-0xa8]
         Entry_GR=1 Save_SP Total_frame_size=8
<main>: [0x58-0x148]
         Entry_GR=2 Save_SP Save_RP Total_frame_size=8
<f>: [0x0-0x38]
         Entry_GR=1 Save_SP Total_frame_size=8

Function f() is listed twice and with different lengths.
Sadly in this example f() starts at offset 0. I think if you tweak
the example, try to see what you get when the start of f() is not zero.

Helge
/who has to run now...

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int a(void)
{
	return 1;
}

int __attribute__((weak)) f(int x)
{
	return 0;
}

int z(void)
{
	return 2;
}

int main(void)
{
	return a() + f(0) + z();
}

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int f(int x)
{
	return 500;
}

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