/3rd_party/llvm/utils/findoptdiff

  1#!/bin/bash
  2#
  3#  findoptdiff
  4#
  5#      This script helps find the optimization difference between two llvm
  6#      builds. It is useful when you have a build that is known to work and
  7#      one that exhibits an optimization problem. Identifying the difference
  8#      between the two builds can lead to discovery of the source of a
  9#      mis-optimization.
 10#
 11#      The script takes two llvm build paths as arguments. These specify the
 12#      the two llvm builds to compare. It is generally expected that they
 13#      are "close cousins".  That is, they are the same except that the 
 14#      second build contains some experimental optimization features that
 15#      are suspected of producing a misoptimization.
 16#
 17#      The script takes two bitcode files, one from each build. They are
 18#      presumed to be a compilation of the same program or program fragment
 19#      with the only difference being the builds.
 20#
 21#      The script operates by iteratively applying the optimizations that gccas
 22#      and gccld run until there is a difference in the assembly resulting
 23#      from the optimization. The difference is then reported with the set of
 24#      optimization passes that produce the difference.  The processing 
 25#      continues until all optimization passes have been tried. The differences
 26#      for each pass, if they do differ, are placed in a diffs.# file.
 27#
 28#      To work around differences in the assembly language format, the script
 29#      can also take two filter arguments that post-process the assembly 
 30#      so they can be differenced without making false positives for known
 31#      differences in the two builds. These filters are optional.
 32#
 33#   Usage:
 34#      findoptdiff llvm1 llvm2 bc1 bc2 filter1 filter2
 35#
 36#   Where:
 37#      llvm1
 38#          is the path to the first llvm build dir
 39#      llvm2
 40#          is the path to the second llvm build dir
 41#      bc1
 42#          is the bitcode file for the first llvm environment
 43#      bc2
 44#          is the bitcode file for the second llvm environment
 45#      filter1
 46#          is an optional filter for filtering the llvm1 generated assembly
 47#      filter2
 48#          is an optional filter for filtering the llvm2 generated assembly
 49#       
 50llvm1=$1
 51llvm2=$2
 52bc1=$3
 53bc2=$4
 54filt1=$5
 55filt2=$6
 56if [ -z "$filt1" ] ; then
 57  filt1="cat"
 58fi
 59if [ -z "$filt2" ] ; then
 60  filt2="cat"
 61fi
 62opt1="${bc1}.opt"
 63opt2="${bc2}.opt" 
 64ll1="${bc1}.ll"
 65ll2="${bc2}.ll"
 66opt1ll="${bc1}.opt.ll"
 67opt2ll="${bc2}.opt.ll"
 68dis1="$llvm1/Debug/bin/llvm-dis"
 69dis2="$llvm2/Debug/bin/llvm-dis"
 70opt1="$llvm1/Debug/bin/opt"
 71opt2="$llvm2/Debug/bin/opt"
 72
 73all_switches="-verify -lowersetjmp -simplifycfg -mem2reg -globalopt -globaldce -ipconstprop -deadargelim -instcombine -simplifycfg -prune-eh -inline -simplify-libcalls -argpromotion -tailduplicate -simplifycfg -scalarrepl -instcombine -predsimplify -condprop -tailcallelim -simplifycfg -reassociate -licm -loop-unswitch -instcombine -indvars -loop-unroll -instcombine -load-vn -gcse -sccp -instcombine -condprop -dse -dce -simplifycfg -deadtypeelim -constmerge -internalize -ipsccp -globalopt -constmerge -deadargelim -inline -prune-eh -globalopt -globaldce -argpromotion -instcombine -predsimplify -scalarrepl -globalsmodref-aa -licm -load-vn -gcse -dse -instcombine -simplifycfg -verify"
 74
 75#counter=0
 76function tryit {
 77  switches_to_use="$1"
 78  $opt1 $switches_to_use "$bc1" -o - | $dis1 | $filt1 > "$opt1ll"
 79  $opt2 $switches_to_use "$bc2" -o - | $dis2 | $filt2 > "$opt2ll"
 80  diffs="diffs."$((counter++))
 81  diff "$opt1ll" "$opt2ll" > $diffs
 82  if [ $? -ne 0 ] ; then
 83    echo
 84    echo "Diff fails with these switches:"
 85    echo $switches
 86    echo "Differences:"
 87    head $diffs
 88    echo 'Switches:' $switches_to_use >> $diffs
 89  else
 90    rm $diffs
 91  fi
 92  return 1
 93}
 94
 95for sw in $all_switches ; do
 96  echo -n " $sw"
 97  switches="$switches $sw"
 98  if tryit "$switches" ; then
 99    break;
100  fi
101done