m68k-aout-g++ : Strange data generated to .data section __GLOBAL__F_*

m68k-aout-g++ : Strange data generated to .data section __GLOBAL__F_*

[Vincent Riviere]

Hello.

I'm experiencing strange behavior with m68k-aout-g++ :

// Source file : mytest.cc
extern "C" void func2();

extern "C" void func1()
{
    func2();
}


$ m68k-unknown-aout-g++ mytest.cc ; cat mytest.s
#NO_APP
    .text
    .even
    .globl _func1
_func1:
LFB3:
    link a6,#0
LCFI0:
    jbsr _func2
    unlk a6
    rts
LFE3:
    .data
    .even
    .globl __GLOBAL__F_func1
    __GLOBAL__F_func1:
Lframe1:
    .long LECIE1-LSCIE1
LSCIE1:
    .long 0x0
    .byte 0x1
    .ascii "zP\0"
    .uleb128 0x1
    .sleb128 -4
    .byte 0x18
    .uleb128 0x5
    .byte 0x0
    .long ___gxx_personality_v0
    .byte 0xc
    .uleb128 0xf
    .uleb128 0x4
    .byte 0x98
    .uleb128 0x1
    .even
LECIE1:
LSFDE1:
    .long LEFDE1-LASFDE1
LASFDE1:
    .long LASFDE1-Lframe1
    .long LFB3
    .long LFE3-LFB3
    .uleb128 0x0
    .byte 0x4
    .long LCFI0-LFB3
    .byte 0x8e
    .uleb128 0x2
    .byte 0xc
    .uleb128 0xe
    .uleb128 0x8
    .even
LEFDE1:
    .long 0x0



What is all that stuff put into the .data section, after __GLOBAL__F_func1 ?
It disappears if I compile the source with --no-exceptions... so I guess it might be related to exception unwinding ?

That code looks very odd... is it normal ?

Vincent.

Re: m68k-aout-g++ : Strange data generated to .data section __GLOBAL__F_*

[Andreas Schwab]

"Vincent Riviere" <vincent.riviere@9online.fr> writes:

> What is all that stuff put into the .data section, after __GLOBAL__F_func1 ?
> It disappears if I compile the source with --no-exceptions... so I guess it might be related to exception unwinding ?

Correct.

> That code looks very odd... is it normal ?

Yes.

Andreas.

-- 
Andreas Schwab, SuSE Labs, schwab@suse.de
SuSE Linux AG, Deutschherrnstr. 15-19, D-90429 Nürnberg
Key fingerprint = 58CA 54C7 6D53 942B 1756  01D3 44D5 214B 8276 4ED5
"And now for something completely different."

Re: m68k-aout-g++ : Strange data generated to .data section __GLOBAL__F_*

[Vincent Riviere]

I finally understood that the strange stuff was dwarf2 frame unwind information.

I got rid of it by putting the followin line un GCC config file :
#define DWARF2_UNWIND_INFO 0

Now it works fine with SjLj exceptions.

Re: m68k-aout-g++ : Strange data generated to .data section __GLOBAL__F_*

[Andreas Schwab]

"Vincent Riviere" <vincent.riviere@9online.fr> writes:

> I finally understood that the strange stuff was dwarf2 frame unwind information.
>
> I got rid of it by putting the followin line un GCC config file :
> #define DWARF2_UNWIND_INFO 0

Configure with --enable-sjlj-exceptions.

Andreas.

-- 
Andreas Schwab, SuSE Labs, schwab@suse.de
SuSE Linux AG, Deutschherrnstr. 15-19, D-90429 Nürnberg
Key fingerprint = 58CA 54C7 6D53 942B 1756  01D3 44D5 214B 8276 4ED5
"And now for something completely different."