need better compiler error/diagnistics output

[yonghong-song]

The following is a buggy b-language program.
plumgrid@yhs-plumgrid:~/iovisor/bcc/tests/jit$ cat bpfdev1.b

packed "false"

// hash
struct FwdKey {
u32 dip:32;
};
struct FwdLeaf {
u32 ifindex:32;
};
Table<FwdKey, FwdLeaf, FIXED_MATCH, NONE> fwd_map(1);

// array
struct ConfigKey {
u32 index:32;
};
struct ConfigLeaf {
u32 bpfdev_ip:32;
u32 slave_ip:32;
};
Table<ConfigKey, ConfigLeaf, INDEXED, NONE> config_map(1);

// hash
struct MacaddrKey {
u32 ip:32;
};
struct MacaddrLeaf {
u64 mac:48;
};
Table<MacaddrKey, MacaddrLeaf, FIXED_MATCH, AUTO> macaddr_map(11);

// hash
struct SlaveKey {
u32 slave_ip:32;
};
struct SlaveLeaf {
u32 slave_ifindex:32;
};
Table<SlaveKey, SlaveLeaf, FIXED_MATCH, NONE> slave_map(10);

u32 main(struct proto::skbuff *skb) {
u32 ret:32 = 0xffffffff;

goto proto::ethernet;

state proto::ethernet {
}

state proto::dot1q {
}

if (skb.pkt_type) {
state proto::arp {
if $arp.oper != 1 {
return 0;
}
macaddr_map[$arp.spa] = $arp.sha;
}
state proto::ip {
}
state proto::udp {
if $udp.dport != 5000 {
return 0;
}
FwdKey fwd_key = {.dip = $ip.dst};
FwdLeaf *fwd_idx_p = fwd_map[$ip.dst];
if (fwd_idx_p) {
return fwd_idx_p->fwd_idx;
} else {
return 0;
}
}
} else {
state proto::ip {
}
}

state EOP {
return ret;
}
}
plumgrid@yhs-plumgrid:~/iovisor/bcc/tests/jit$

The compiler error message like the below:

Checking test dependency graph end
test 5
Start 5: py_bpfdev1

5: Test command: /home/plumgrid/iovisor/bcc/build/tests/wrapper.sh "py_bpfdev1" "/home/plumgrid/iovisor/bcc/tests/jit/bpfdev1.py" "namespace"
5: Test timeout computed to be: 9.99988e+06
5: Error: 42.1-5 syntax error
5: In file: bpfdev1.b
5: E

It does not provide sufficient information about where the problem occurs.
Maybe 42.1-5 indicates something, but the message should be better communicated.

[drzaeus77]

Closing this as the clang frontend has much better diagnostics now.