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:
> 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 */

Can you please clone my git tree and try it from there?

git clone git://git.kernel.org/pub/scm/devel/pahole/pahole
cd pahole
mkdir build
cd build
cmake ..
cd ..
make -C build
build/pahole brainfart.o

Now I'm getting:

[acme@sandy pahole]$ build/pahole brainfart.o 
class ios_base {
	static enum _Ios_Openmodeconst    in = 8;        /*     0     0 */
	typedef enum _Ios_Fmtflags fmtflags;


	/* size: 1, cachelines: 0, members: 0, static members: 1 */
	/* last cacheline: 1 bytes */
};
[acme@sandy pahole]$

I still need to get the 'const' there, from the fact that it has a
DW_AT_const_value, that is already captured, just forgot to add the
'const' there, will do after some errands here.

Also I'll check that the member type is an enum, will lookup the
enumerator entry that has the DW_AT_const_value and replace that '8'
with it.

- Arnaldo
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