On Tue, Nov 29, 2016 at 9:01 AM, Alexei Starovoitov <alexei.starovoi...@gmail.com> wrote: >> >If I try to run samples/bpf/test_cls_bpf.sh the verifier will complain: >> >R0=imm0,min_value=0,max_value=0 R1=pkt(id=0,off=0,r=42) R2=pkt_end >> >112: (0f) r4 += r3 >> >113: (0f) r1 += r4 >> >114: (b7) r0 = 2 >> >115: (69) r2 = *(u16 *)(r1 +2) >> >invalid access to packet, off=2 size=2, R1(id=3,off=0,r=0) >> > >> >Now multiply 115 * 8 and convert to hex. This is address 0x398 in >> >llvm-objdump: >> >; struct udphdr *udp = data + tp_off; >> > 388: r1 += r4 >> > 390: r0 = 2 >> >; if (udp->dest == htons(DEFAULT_PKTGEN_UDP_PORT) || >> > 398: r2 = *(u16 *)(r1 + 2) >> > 3a0: if r2 == 2304 goto 16 >> > >> >Now it's clear which line of C code is causing the verifier to reject. >> [...] >> >> Could llvm-objdump switch line numbering for bpf same way as verifier >> output, so mapping step is not really needed? > > you mean that llvm-objdump to print 113,114,115 ? > I guess it's doable. Will give it a try.
Hi Daniel, your feature request turned out to be pretty straightforward to implement. Please pull the latest llvm and rebuild llvm-objdump. It will be printing instruction numbers instead of absolute addresses. No "multiply 115 * 8 and convert to hex" steps necessary anymore. Thanks
