#!/bin/bash
# Compare dependency graph and map sybols from xmle files.
#
#  Copyright (C) 2014-2023 Ryan Specialty, LLC.
#
#  This program is free software: you can redistribute it and/or modify
#  it under the terms of the GNU General Public License as published by
#  the Free Software Foundation, either version 3 of the License, or
#  (at your option) any later version.
#
#  This program is distributed in the hope that it will be useful,
#  but WITHOUT ANY WARRANTY; without even the implied warranty of
#  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#  GNU General Public License for more details.
#
#  You should have received a copy of the GNU General Public License
#  along with this program.  If not, see <http://www.gnu.org/licenses/>.
#
# <l:dep> and <l:map-from> are extracted, genearted symbols are removed, the
# resulting symbol sets are sorted, and the result is diff'd between the
# two files.
#
# The intent of this tool is to verify that a set of symbols has not changed
# after having made changes to the compiler or linker (or anything else,
# really).  Note that this does not testing the _ordering_ of the symbols,
# because there are many valid topological orderings.
#


set -euo pipefail

# xmllint has a size limit that it hits on larger programs, so remove parts
# we do not care about
truncate-exec() {
  local path="${1?}"

  # Note that this also removes newlines, so it's easy to parse with sed
  # without having to use the hold space.  Replaces everything after the
  # first exec block until the end of the package.
  tr '\n' ' ' < "$path" | sed 's|<l:[a-z-]*exec>.*</package>|</package>|'
}

fmt-symbols() {
  local path="${1?}"

  truncate-exec "$path" \
    | xmllint --format - \
    | awk '
        /<l:dep>$/,/<\/l:dep>$/
        /<l:map-from>$/,/<\/l:map-from>$/
      ' \
    | sed '
        # replace generated identifier names, while leaving all other attributes
        s/\(name\|yields\|parent\)="[^"]\+_pu[0-9a-f]\+_[^"]\+"/\1="(generated)"/g
      ' \
    | sort
}

main() {
  local a="${1?}"
  local b="${2?}"

  diff <( fmt-symbols "$a" ) <( fmt-symbols "$b" )
}

main "$@"