Em Thu, Jun 07, 2018 at 01:07:01PM -0700, Martin KaFai Lau escreveu:
> On Thu, Jun 07, 2018 at 04:30:29PM -0300, Arnaldo Carvalho de Melo wrote:
> > So this must be available in a newer llvm version? Which one?
> I should have put in the details in my last email or
> in the commit message, my bad.
> 1. The tools/testing/selftests/bpf/Makefile has the CLANG_FLAGS and
> LLC_FLAGS needed to compile the bpf prog. It requires a new
> "-mattr=dwarf" llc option which was added to the future
> llvm 7.0.
> Hence, I have been using the llvm's master in github which
> also has the llvm-objcopy.
> 2. The kernel's btf part only focus on the BPF map.
> Hence, the testing bpf program should have the map's key
> and map's value. e.g. tools/testing/selftests/bpf/test_btf_haskv.c
So, with llvm and clang HEAD I get:
[root@jouet bpf]# pahole -J hello.o
[root@jouet bpf]# file hello.o
hello.o: ELF 64-bit LSB relocatable, *unknown arch 0xf7* version 1 (SYSV), with
debug_info, not stripped
[root@jouet bpf]# llvm-readelf -s hello.o
There are 26 section headers, starting at offset 0xe30:
Section Headers:
[Nr] Name Type Address Off Size ES Flg
Lk Inf Al
[ 0] NULL 0000000000000000 000000 000000 00
0 0 0
[ 1] .text PROGBITS 0000000000000000 000040 000000 00 AX
0 0 4
[ 2] syscalls:sys_enter_openat PROGBITS 0000000000000000 000040 000088 00 AX
0 0 8
[ 3] license PROGBITS 0000000000000000 0000c8 000004 00 WA
0 0 1
[ 4] version PROGBITS 0000000000000000 0000cc 000004 00 WA
0 0 4
[ 5] maps PROGBITS 0000000000000000 0000d0 000010 00 WA
0 0 4
[ 6] .rodata.str1.1 PROGBITS 0000000000000000 0000e0 00000e 01 AMS
0 0 1
[ 7] .debug_str PROGBITS 0000000000000000 0000ee 00010e 01 MS
0 0 1
[ 8] .debug_loc PROGBITS 0000000000000000 0001fc 000023 00
0 0 1
[ 9] .debug_abbrev PROGBITS 0000000000000000 00021f 0000e3 00
0 0 1
[10] .debug_info PROGBITS 0000000000000000 000302 00015e 00
0 0 1
[11] .debug_ranges PROGBITS 0000000000000000 000460 000030 00
0 0 1
[12] .debug_macinfo PROGBITS 0000000000000000 000490 000001 00
0 0 1
[13] .debug_pubnames PROGBITS 0000000000000000 000491 00006e 00
0 0 1
[14] .debug_pubtypes PROGBITS 0000000000000000 0004ff 00005a 00
0 0 1
[15] .debug_frame PROGBITS 0000000000000000 000560 000028 00
0 0 8
[16] .debug_line PROGBITS 0000000000000000 000588 00006e 00
0 0 1
[17] .symtab SYMTAB 0000000000000000 0005f8 000318 18
24 29 8
[18] .relsyscalls:sys_enter_openat REL 0000000000000000 000910 000010 10
17 2 8
[19] .rel.debug_info REL 0000000000000000 000920 0001e0 10
17 10 8
[20] .rel.debug_pubnames REL 0000000000000000 000b00 000010 10
17 13 8
[21] .rel.debug_pubtypes REL 0000000000000000 000b10 000010 10
17 14 8
[22] .rel.debug_frame REL 0000000000000000 000b20 000020 10
17 15 8
[23] .rel.debug_line REL 0000000000000000 000b40 000010 10
17 16 8
[24] .strtab STRTAB 0000000000000000 000b50 00018e 00
0 0 1
[25] .BTF PROGBITS 0000000000000000 000cde 00014e 00
0 0 1
Key to Flags:
W (write), A (alloc), X (execute), M (merge), S (strings), l (large)
I (info), L (link order), G (group), T (TLS), E (exclude), x (unknown)
O (extra OS processing required) o (OS specific), p (processor specific)
[root@jouet bpf]#
[root@jouet bpf]# pahole hello.o
struct clang version 5.0.1 (tags/RELEASE_501/final) {
clang version 5.0.1 (tags/RELEASE_501/final) clang version 5.0.1
(tags/RELEASE_501/final); /* 0 4 */
clang version 5.0.1 (tags/RELEASE_501/final) clang version 5.0.1
(tags/RELEASE_501/final); /* 4 4 */
clang version 5.0.1 (tags/RELEASE_501/final) clang version 5.0.1
(tags/RELEASE_501/final); /* 8 4 */
clang version 5.0.1 (tags/RELEASE_501/final) clang version 5.0.1
(tags/RELEASE_501/final); /* 12 4 */
/* size: 16, cachelines: 1, members: 4 */
/* last cacheline: 16 bytes */
};
[root@jouet bpf]#
Ok, I guess I saw this case in the llvm/clang git logs, so this one was
generated with the older clang, will regenerate and add that "-mattr=dwarf"
part.
- Arnaldo
