[BPF] Avoid generating .comment section (#159958)
The kernel libbpf does not need .comment section. If not filtering out
in llvm, the section will be filtered out in libbpf. So let us filter it
out as early as possible which is in llvm.
The following is an example.
$ cat t.c
int test() { return 5; }
Without this change:
$ llvm-readelf -S t.o
[Nr] Name Type Address Off Size ES Flg Lk Inf Al
[ 0] NULL 0000000000000000 000000 000000 00 0 0 0
[ 1] .strtab STRTAB 0000000000000000 000110 000047 00 0 0 1
[ 2] .text PROGBITS 0000000000000000 000040 000010 00 AX 0 0 8
[ 3] .comment PROGBITS 0000000000000000 000050 000072 01 MS 0 0 1
[ 4] .note.GNU-stack PROGBITS 0000000000000000 0000c2 000000 00 0 0 1
[ 5] .llvm_addrsig LLVM_ADDRSIG 0000000000000000 000110 000000 00 E 6 0 1
[ 6] .symtab SYMTAB 0000000000000000 0000c8 000048 18 1 2 8
With this change:
$ llvm-readelf -S t.o
[Nr] Name Type Address Off Size ES Flg Lk Inf Al
[ 0] NULL 0000000000000000 000000 000000 00 0 0 0
[ 1] .strtab STRTAB 0000000000000000 000098 00003e 00 0 0 1
[ 2] .text PROGBITS 0000000000000000 000040 000010 00 AX 0 0 8
[ 3] .note.GNU-stack PROGBITS 0000000000000000 000050 000000 00 0 0 1
[ 4] .llvm_addrsig LLVM_ADDRSIG 0000000000000000 000098 000000 00 E 5 0 1
[ 5] .symtab SYMTAB 0000000000000000 000050 000048 18 1 2 8
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