Em Thu, Jan 10, 2019 at 11:39:06AM -0800, Yonghong Song escreveu:
> Added int128 types to dwarf base_type_name_to_size table
> so that the correct base type size can be retrieved in certain
> cases. Note that for type "unsigned __int128", the dwarf in gcc
> has type name "__int128 unsigned" while clang has
> "unsigned __int128".
>
> -bash-4.4$ cat t.c
> struct t {
> __int128 si128a;
> __int128 si128b;
> unsigned __int128 bits3:3;
> unsigned __int128 bits80:80;
> unsigned __int128 ui128;
> } g;
> -bash-4.4$ clang -O2 -c -g -target bpf -Xclang -target-feature -Xclang +dwarfris t.c
> -bash-4.4$ pahole -F dwarf t.o
> struct t {
> __int128 si128a; /* 0 16 */
> __int128 si128b; /* 16 16 */
> unsigned __int128 bits3:3; /* 32:125 16 */
> unsigned __int128 bits80:80; /* 32:45 16 */
>
> /* XXX 45 bits hole, try to pack */
>
> unsigned __int128 ui128; /* 48 16 */
>
> /* size: 64, cachelines: 1, members: 5 */
> /* bit holes: 1, sum bit holes: 45 bits */
> };
> -bash-4.4$ pahole -F btf t.o
> struct t {
> __int128 si128a; /* 0 16 */
> __int128 si128b; /* 16 16 */
> unsigned __int128 bits3:3; /* 32:125 16 */
> unsigned __int128 bits80:80; /* 32:45 16 */
>
> /* XXX 45 bits hole, try to pack */
>
> unsigned __int128 ui128; /* 48 16 */
>
> /* size: 64, cachelines: 1, members: 5 */
> /* bit holes: 1, sum bit holes: 45 bits */
> };
cool, at first I got briefly confused with the 32:125 16, part, but just
for a momentm its byte_offset:bit_offset byte_size, all is right, thanks
for the patch, applied!
Now its just a matter of combing cu__fixup_btf_bitfields() to figure out
the packed struct case...
- Arnaldo
