Re: abidiff improvements for kernel UAPI checker

[John Moon <quic_johmoo@quicinc.com>]

On 9/22/2023 11:28 AM, John Moon via Libabigail wrote:
> If not, I think this output is at least easier to post-process! For 
> example, I could add logic to the script to do something like "if 
> there's a deleted enum whose contents are present in an added enum, 
> assume it's an addition to an anonymous enum and ignore".
> 


Proof of concept to filter out anon enum additions from input like this:

   2 removed types unreachable from any public interface:
     [D] 'enum {HNS_ROCE_EXSGE_FLAGS=1, HNS_ROCE_RQ_INLINE_FLAGS=2, }' 
at hns-abi.h:88:1
     [D] 'enum {HNS_ROCE_RSP_EXSGE_FLAGS=1, 
HNS_ROCE_RSP_RQ_INLINE_FLAGS=2, }' at hns-abi.h:93:1
   2 added types unreachable from any public interface:
     [A] 'enum {HNS_ROCE_CQE_INLINE_FLAGS=4, HNS_ROCE_EXSGE_FLAGS=1, 
HNS_ROCE_RQ_INLINE_FLAGS=2, }' at hns-abi.h:88:1
     [A] 'enum {HNS_ROCE_RSP_CQE_INLINE_FLAGS=4, 
HNS_ROCE_RSP_EXSGE_FLAGS=1, HNS_ROCE_RSP_RQ_INLINE_FLAGS=2, }' at 
hns-abi.h:94:1

---
#!/bin/bash
set -o errexit

# Take a line and form a normalized string representation
get_repr() {
   local -r line="$1"
   echo "$line" | grep -o '{.*}' \
                | tr -d '{} ' \
                | sed -e 's/,$//g' -e 's/,/\n/g' \
                | sort -t= -k2 -n \
                | xargs
}

input="${1:-/dev/stdin}"
deleted_anon_enum_reprs=()
added_anon_enum_reprs=()
while read -r line; do
   if echo "$line" | grep -q "\[D\] 'enum {"; then
     deleted_anon_enum_reprs+=("$(get_repr "$line")")
   fi
   if echo "$line" | grep -q "\[A\] 'enum {"; then
     added_anon_enum_reprs+=("$(get_repr "$line")")
   fi
done < "$input"

# If a deleted enum's representation appears in an added enum's
# representation, assume they're the same enum (just being added
# on to).
legit_breaks=${#deleted_anon_enum_reprs[@]}
for del_repr in "${deleted_anon_enum_reprs[@]}"; do
   for add_repr in "${added_anon_enum_reprs[@]}"; do
     if echo "$add_repr" | grep -q "^${del_repr}"; then
       legit_breaks=$((legit_breaks - 1))
       break
     fi
   done
done

echo "$legit_breaks breaks"
---

There may be a better way to do this sort of thing in a suppression, but 
I'm not sure how given they operate on diffs (which wouldn't be created 
in this case).

It feels hacky as the abidiff stdout isn't a stable API itself, but if 
it sounds reasonable to you, I can bake the above filtering logic into 
the next rev submitted upstream. Just let me know!

Thanks,
John