abg-dwarf-reader.cc - trouble with GNU hash tables

abg-dwarf-reader.cc - trouble with GNU hash tables

[Giuliano Procida]

Looking up symbols in shared objects with .gnu.hash sections doesn't
always work. There is something not right with the Bloom filter code.

Testing notes follow. Ideally we should create files targeting a
diversity of architectures (word size, endianness, special ones like
Alpha and S390).

for y in {0..999}; do echo $(printf "int x%03d = $y;" $y); done > extern.c
gcc -g -Wall -W -fPIC --shared -c extern.c -o extern.o
ld -fPIC --shared --soname foo extern.o -o extern.so
for y in {0..999}; do sym=$(printf "x%03d" $y); build/tools/abisym
extern.so "$sym"; done | grep -c ^could
--> should be 0

Giuliano.

Re: abg-dwarf-reader.cc - trouble with GNU hash tables

[Dodji Seketeli]

Hello Giuliano,

Giuliano Procida via Libabigail <libabigail@sourceware.org> a écrit:

> Looking up symbols in shared objects with .gnu.hash sections doesn't
> always work. There is something not right with the Bloom filter code.

Hopefully, the patch at
https://sourceware.org/git/?p=libabigail.git;a=commit;h=b1b0586dc208726bd5de5728caf1ead119413fce
should address that.

> Testing notes follow. Ideally we should create files targeting a
> diversity of architectures (word size, endianness, special ones like
> Alpha and S390).
>
> for y in {0..999}; do echo $(printf "int x%03d = $y;" $y); done > extern.c
> gcc -g -Wall -W -fPIC --shared -c extern.c -o extern.o
> ld -fPIC --shared --soname foo extern.o -o extern.so
> for y in {0..999}; do sym=$(printf "x%03d" $y); build/tools/abisym
> extern.so "$sym"; done | grep -c ^could
> --> should be 0
>

Thanks for the test.  I ran it on ppc64 an amd64 at least.

We'll see what the builders over at
https://builder.wildebeest.org/buildbot report.

Cheers,

-- 
		Dodji