Re: Brain fart alert

[Arnaldo Carvalho de Melo <acme-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org>]

Em Sat, Jul 21, 2012 at 08:22:33PM +0200, Nicolas escreveu:
> Hello,
> 
> I tried using pahole, but I get a brain fart alert with the file
> attached (which is an extract from stdio.h). I'm running dwarves 1.10,
> libdw1 0.152 and g++ 4.6.1, on i386.
> 
> Here is what I get:
> 
> $ g++ -Wall -g -c brainfart.cpp -o brainfart.o && pahole brainfart.o
> class ios_base {
> 	enum _Ios_Openmodeconst    in;                   /*     0     4 */
> 	typedef enum _Ios_Fmtflags fmtflags;
> 
> 
> 	/* size: 1, cachelines: 1, members: 1 */
> 	/* padding: 65533 */
> 	/* last cacheline: 1 bytes */
> 
> 	/* BRAIN FART ALERT! 1 != 4 + 0(holes), diff = -3 */
> 
> };
> 
> Moreover, on amd64, pahole segfaults if I do the same (with dwarves
> 1.10, libdw1 0.152, g++ 4.6.3).

that is strange, I just tried it on rhel6, x86_64, and just reproduced
what you describe on i386:

[acme@sandy pahole]$ uname -a
Linux sandy.ghostprotocols.net 3.6.0-rc1+ #13 SMP Fri Aug 10 12:42:33 BRT 2012 x86_64 x86_64 x86_64 GNU/Linux
[acme@sandy pahole]$ g++ -Wall -g -c brainfart.cpp -o brainfart.o && pahole brainfart.o
class ios_base {
	enum _Ios_Openmodeconst    in;                   /*     0     4 */
	typedef enum _Ios_Fmtflags fmtflags;


	/* size: 1, cachelines: 1, members: 1 */
	/* padding: 65533 */
	/* last cacheline: 1 bytes */

	/* BRAIN FART ALERT! 1 != 4 + 0(holes), diff = -3 */

};
[acme@sandy pahole]$ file brainfart.o
brainfart.o: ELF 64-bit LSB relocatable, x86-64, version 1 (SYSV), not stripped
[acme@sandy pahole]$

will try to fix this on the plane later today,

thanks for reporting and sorry for the late response,

- Arnaldo
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