llvm/utils/findmisopt

   1 #!/bin/bash
   2 #
   3 #  findmisopt
   4 #
   5 #      This is a quick and dirty hack to potentially find a misoptimization
   6 #      problem. Mostly its to work around problems in bugpoint that prevent
   7 #      it from finding a problem unless the set of failing optimizations are
   8 #      known and given to it on the command line.
   9 #
  10 #      Given a bitcode file that produces correct output (or return code),
  11 #      this script will run through all the optimizations passes that gccas
  12 #      uses (in the same order) and will narrow down which optimizations
  13 #      cause the program either generate different output or return a
  14 #      different result code. When the passes have been narrowed down,
  15 #      bugpoint is invoked to further refine the problem to its origin. If a
  16 #      release version of bugpoint is available it will be used, otherwise
  17 #      debug.
  18 #
  19 #   Usage:
  20 #      findmisopt bcfile outdir progargs [match]
  21 #
  22 #   Where:
  23 #      bcfile
  24 #          is the bitcode file input (the unoptimized working case)
  25 #      outdir
  26 #          is a directory into which intermediate results are placed
  27 #      progargs
  28 #          is a single argument containing all the arguments the program needs
  29 #      proginput
  30 #          is a file name from which stdin should be directed
  31 #      match
  32 #          if specified to any value causes the result code of the program to
  33 #          be used to determine success/fail. If not specified success/fail is
  34 #          determined by diffing the program's output with the non-optimized
  35 #          output.
  36 #
  37 if [ "$#" -lt 3 ] ; then
  38   echo "usage: findmisopt bcfile outdir progargs [match]"
  39   exit 1
  40 fi
  41
  42 dir="${0%%/utils/findmisopt}"
  43 if [ -x "$dir/Release/bin/bugpoint" ] ; then
  44   bugpoint="$dir/Release/bin/bugpoint"
  45 elif [ -x "$dir/Debug/bin/bugpoint" ] ; then
  46   bugpoint="$dir/Debug/bin/bugpoint"
  47 else
  48   echo "findmisopt: bugpoint not found"
  49   exit 1
  50 fi
  51
  52 bcfile="$1"
  53 outdir="$2"
  54 args="$3"
  55 input="$4"
  56 if [ ! -f "$input" ] ; then
  57   input="/dev/null"
  58 fi
  59 match="$5"
  60 name=`basename $bcfile .bc`
  61 ll="$outdir/${name}.ll"
  62 s="$outdir/${name}.s"
  63 prog="$outdir/${name}"
  64 out="$outdir/${name}.out"
  65 optbc="$outdir/${name}.opt.bc"
  66 optll="$outdir/${name}.opt.ll"
  67 opts="$outdir/${name}.opt.s"
  68 optprog="$outdir/${name}.opt"
  69 optout="$outdir/${name}.opt.out"
  70 ldflags="-lstdc++ -lm -ldl -lc"
  71
  72 echo "Test Name: $name"
  73 echo "Unoptimized program: $prog"
  74 echo "  Optimized program: $optprog"
  75
  76 # Define the list of optimizations to run. This comprises the same set of
  77 # optimizations that opt -O3 runs, in the same order.
  78 opt_switches=`llvm-as < /dev/null -o - | opt -O3 -disable-output -debug-pass=Arguments 2>&1 | sed 's/Pass Arguments: //'`
  79 all_switches="$opt_switches"
  80 echo "Passes : $all_switches"
  81
  82 # Create output directory if it doesn't exist
  83 if [ -f "$outdir" ] ; then
  84   echo "$outdir is not a directory"
  85   exit 1
  86 fi
  87
  88 if [ ! -d "$outdir" ] ; then
  89   mkdir "$outdir" || exit 1
  90 fi
  91
  92 # Generate the disassembly
  93 llvm-dis "$bcfile" -o "$ll" -f || exit 1
  94
  95 # Generate the non-optimized program and its output
  96 llc "$bcfile" -o "$s" -f || exit 1
  97 gcc "$s" -o "$prog" $ldflags || exit 1
  98 "$prog" $args > "$out" 2>&1 <$input
  99 ex1=$?
 100
 101 # Current set of switches is empty
 102 function tryit {
 103   switches_to_use="$1"
 104   opt $switches_to_use "$bcfile" -o "$optbc" -f || exit
 105   llvm-dis "$optbc" -o "$optll" -f || exit
 106   llc "$optbc" -o "$opts" -f || exit
 107   gcc "$opts" -o "$optprog" $ldflags || exit
 108   "$optprog" $args > "$optout" 2>&1 <"$input"
 109   ex2=$?
 110
 111   if [ -n "$match" ] ; then
 112     if [ "$ex1" -ne "$ex2" ] ; then
 113       echo "Return code not the same with these switches:"
 114       echo $switches
 115       echo "Unoptimized returned: $ex1"
 116       echo "Optimized   returned: $ex2"
 117       return 0
 118     fi
 119   else
 120     diff "$out" "$optout" > /dev/null
 121     if [ $? -ne 0 ] ; then
 122       echo "Diff fails with these switches:"
 123       echo $switches
 124       echo "Differences:"
 125       diff "$out" "$optout" | head
 126       return 0;
 127     fi
 128   fi
 129   return 1
 130 }
 131
 132 echo "Trying to find optimization that breaks program:"
 133 for sw in $all_switches ; do
 134   echo -n " $sw"
 135   switches="$switches $sw"
 136   if tryit "$switches" ; then
 137     break;
 138   fi
 139 done
 140
 141 # Terminate the previous output with a newline
 142 echo ""
 143
 144 # Determine if we're done because none of the optimizations broke the program
 145 if [ "$switches" == " $all_switches" ] ; then
 146   echo "The program did not miscompile"
 147   exit 0
 148 fi
 149
 150 final=""
 151 while [ ! -z "$switches" ] ; do
 152   trimmed=`echo "$switches" | sed -e 's/^ *\(-[^ ]*\).*/\1/'`
 153   switches=`echo "$switches" | sed -e 's/^ *-[^ ]* *//'`
 154   echo "Trimmed $trimmed from left"
 155   tryit "$final $switches"
 156   if [ "$?" -eq "0" ] ; then
 157     echo "Still Failing .. continuing ..."
 158     continue
 159   else
 160     echo "Found required early pass: $trimmed"
 161     final="$final $trimmed"
 162     continue
 163   fi
 164   echo "Next Loop"
 165 done
 166
 167 if [ "$final" == " $all_switches" ] ; then
 168   echo "findmisopt: All optimizations pass. Perhaps this isn't a misopt?"
 169   exit 0
 170 fi
 171 echo "Smallest Optimization list=$final"
 172
 173 bpcmd="$bugpoint -run-llc -disable-loop-extraction --output "$out" --input /dev/null $bcfile $final --args $args"
 174
 175 echo "Running: $bpcmd"
 176 $bpcmd
 177 echo "findmisopt finished."