Re: Out of order unwind entry warning

[Helge Deller <deller@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...

[-- Attachment #2: t1.c --]
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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();
}

[-- Attachment #3: t2.c --]
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int f(int x)
{
	return 500;
}