pahole --reorganize heavily depends on member's bit_hole and hole fields
to denote bit/byte holes *after* member. Previous commit "dwarves: use
bit sizes and bit/byte hole info in __class__fprintf" changed its
meaning to bit/byte hole *before* member to accomodate possible bit/byte
holes at the beginning of a struct. This change broke reorganization
algorithm, though, which is quite involved and isn't trivially
modifiable to accomodate new semantics.
This patch reverts the meaning of bit_hole and hole, but also introduces
per class pre_bit_hole/pre_hole to record initial bit/byte hole of a
struct. This allows to fix reorg code more easily and still handle
initial holes cases, if at the expense of being not as elegant.
Committer testing:
$ time pahole -F btf --packable vmlinux | sort -nr -k4 | head
bts_ctx 12288 8192 4096
swsusp_info 4096 432 3664
vc_data 792 496 296
pci_dev 2488 2320 168
rcu_state 3392 3240 152
ptr_ring 192 40 152
xdp_sock 960 840 120
zone 1664 1552 112
rcu_data 576 472 104
rcu_node 576 480 96
real 0m0.038s
user 0m0.029s
sys 0m0.017s
$
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Reported-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Alexei Starovoitov <ast@fb.com>
Cc: Yonghong Song <yhs@fb.com>
Cc: dwarves@vger.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Build instructions:
1. install cmake
2. mkdir build
3. cd build
4. cmake -D__LIB=lib ..
5. make install
Default is to be installed on /usr/local, see rpm spec file for
installing on other places.
Known to work scenarios:
Mandriva Cooker:
cmake 2.4.5-1mdv2007.1
libelfutils1-devel 0.123-1mdv2007.1
Debian Unstable:
cmake 2.4.5-1
libdw-dev 0.123-2
Fedora Core 6:
cmake 2.4.5-2.fc6
elfutils-devel 0.126-1.fc6
78c110a7ea