scripts/objdiff

   1 #!/bin/bash
   2
   3 # objdiff - a small script for validating that a commit or series of commits
   4 # didn't change object code.
   5 #
   6 # Copyright 2014, Jason Cooper <jason@lakedaemon.net>
   7 #
   8 # Licensed under the terms of the GNU GPL version 2
   9
  10 # usage example:
  11 #
  12 # $ git checkout COMMIT_A
  13 # $ <your fancy build command here>
  14 # $ ./scripts/objdiff record path/to/*.o
  15 #
  16 # $ git checkout COMMIT_B
  17 # $ <your fancy build command here>
  18 # $ ./scripts/objdiff record path/to/*.o
  19 #
  20 # $ ./scripts/objdiff diff COMMIT_A COMMIT_B
  21 # $
  22
  23 # And to clean up (everything is in .tmp_objdiff/*)
  24 # $ ./scripts/objdiff clean all
  25 #
  26 # Note: 'make mrproper' will also remove .tmp_objdiff
  27
  28 SRCTREE=$(cd $(git rev-parse --show-toplevel 2>/dev/null); pwd)
  29
  30 if [ -z "$SRCTREE" ]; then
  31         echo >&2 "ERROR: Not a git repository."
  32         exit 1
  33 fi
  34
  35 TMPD=$SRCTREE/.tmp_objdiff
  36
  37 usage() {
  38         echo >&2 "Usage: $0 <command> <args>"
  39         echo >&2 "  record    <list of object files or directories>"
  40         echo >&2 "  diff      <commitA> <commitB>"
  41         echo >&2 "  clean     all | <commit>"
  42         exit 1
  43 }
  44
  45 get_output_dir() {
  46         dir=${1%/*}
  47
  48         if [ "$dir" = "$1" ]; then
  49                 dir=.
  50         fi
  51
  52         dir=$(cd $dir; pwd)
  53
  54         echo $TMPD/$CMT${dir#$SRCTREE}
  55 }
  56
  57 do_objdump() {
  58         dir=$(get_output_dir $1)
  59         base=${1##*/}
  60         stripped=$dir/${base%.o}.stripped
  61         dis=$dir/${base%.o}.dis
  62
  63         [ ! -d "$dir" ] && mkdir -p $dir
  64
  65         # remove addresses for a cleaner diff
  66         # http://dummdida.tumblr.com/post/60924060451/binary-diff-between-libc-from-scientificlinux-and
  67         $STRIP -g $1 -R __bug_table -R .note -R .comment -o $stripped
  68         $OBJDUMP -D $stripped | sed -e "s/^[[:space:]]\+[0-9a-f]\+//" -e "s:^$stripped:$1:" > $dis
  69 }
  70
  71 dorecord() {
  72         [ $# -eq 0 ] && usage
  73
  74         FILES="$*"
  75
  76         CMT="`git rev-parse --short HEAD`"
  77
  78         STRIP="${CROSS_COMPILE}strip"
  79         OBJDUMP="${CROSS_COMPILE}objdump"
  80
  81         for d in $FILES; do
  82                 if [ -d "$d" ]; then
  83                         for f in $(find $d -name '*.o')
  84                         do
  85                                 do_objdump $f
  86                         done
  87                 else
  88                         do_objdump $d
  89                 fi
  90         done
  91 }
  92
  93 dodiff() {
  94         [ $# -ne 2 ] && [ $# -ne 0 ] && usage
  95
  96         if [ $# -eq 0 ]; then
  97                 SRC="`git rev-parse --short HEAD^`"
  98                 DST="`git rev-parse --short HEAD`"
  99         else
 100                 SRC="`git rev-parse --short $1`"
 101                 DST="`git rev-parse --short $2`"
 102         fi
 103
 104         DIFF="`which colordiff`"
 105
 106         if [ ${#DIFF} -eq 0 ] || [ ! -x "$DIFF" ]; then
 107                 DIFF="`which diff`"
 108         fi
 109
 110         SRCD="$TMPD/$SRC"
 111         DSTD="$TMPD/$DST"
 112
 113         if [ ! -d "$SRCD" ]; then
 114                 echo >&2 "ERROR: $SRCD doesn't exist"
 115                 exit 1
 116         fi
 117
 118         if [ ! -d "$DSTD" ]; then
 119                 echo >&2 "ERROR: $DSTD doesn't exist"
 120                 exit 1
 121         fi
 122
 123         $DIFF -Nurd $SRCD $DSTD
 124 }
 125
 126 doclean() {
 127         [ $# -eq 0 ] && usage
 128         [ $# -gt 1 ] && usage
 129
 130         if [ "x$1" = "xall" ]; then
 131                 rm -rf $TMPD/*
 132         else
 133                 CMT="`git rev-parse --short $1`"
 134
 135                 if [ -d "$TMPD/$CMT" ]; then
 136                         rm -rf $TMPD/$CMT
 137                 else
 138                         echo >&2 "$CMT not found"
 139                 fi
 140         fi
 141 }
 142
 143 [ $# -eq 0 ] && usage
 144
 145 case "$1" in
 146         record)
 147                 shift
 148                 dorecord $*
 149                 ;;
 150         diff)
 151                 shift
 152                 dodiff $*
 153                 ;;
 154         clean)
 155                 shift
 156                 doclean $*
 157                 ;;
 158         *)
 159                 echo >&2 "Unrecognized command '$1'"
 160                 exit 1
 161                 ;;
 162 esac