xref: /llvm-project-15.0.7/llvm/utils/findmisopt (revision 2e80be82) 
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 bytecode 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.
16#
17#   Usage:
18#      findmisopt bcfile outdir progargs [match]
19#
20#   Where:
21#      bcfile
22#          is the bytecode file input (the unoptimized working case)
23#      outdir
24#          is a directory into which intermediate results are placed
25#      progargs
26#          is a single argument containing all the arguments the program needs
27#       match
28#          if specified to any value causes the result code of the program to
29#          be used to determine success/fail. If not specified success/fail is
30#          determined by diffing the program's output with the non-optimized
31#          output.
32#
33if [ "$#" -lt 3 ] ; then
34  echo "usage: findmisopt bcfile outdir progargs [match]"
35  exit 1
36fi
37
38bcfile="$1"
39outdir="$2"
40args="$3"
41match="$4"
42name=`basename $bcfile .bc`
43ll="$outdir/${name}.ll"
44s="$outdir/${name}.s"
45prog="$outdir/${name}"
46out="$outdir/${name}.out"
47optbc="$outdir/${name}.opt.bc"
48optll="$outdir/${name}.opt.ll"
49opts="$outdir/${name}.opt.s"
50optprog="$outdir/${name}.opt"
51optout="$outdir/${name}.opt.out"
52
53echo "Test Name: $name"
54echo "Unoptimized program: $prog"
55echo "  Optimized program: $optprog"
56
57
58# Generate the disassembly
59llvm-dis "$bcfile" -o "$ll" -f || exit 1
60
61# Generate the non-optimized program
62llc "$bcfile" -o "$s" -f || exit 1
63gcc "$s" -o "$prog" -lstdc++ -lc -lm || exit 1
64
65# Define the list of optimizations to run
66all_switches="-verify -lowersetjmp -funcresolve -raiseallocs -simplifycfg -mem2reg -globalopt -globaldce -ipconstprop -deadargelim -instcombine -simplifycfg -prune-eh -inline -simplify-libcalls -argpromotion -raise -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"
67
68# Current set of switches is empty
69function tryit {
70  switches_to_use="$1"
71  opt $switches_to_use "$bcfile" -o "$optbc" -f || exit
72  llvm-dis "$optbc" -o "$optll" -f || exit
73  llc "$optbc" -o "$opts" -f || exit
74  gcc "$opts" -o "$optprog" -lstdc++ -lc -lm || exit
75  "$prog" $args > "$out"
76  ex1=$?
77  "$optprog" $args > "$optout"
78  ex2=$?
79
80  if [ -n "$match" ] ; then
81    if [ "$ex1" -ne "$ex2" ] ; then
82      echo "Return code not the same with these switches:"
83      echo $switches
84      echo "Unoptimized returned: $ex1"
85      echo "Optimized   returned: $ex2"
86      return 0
87    fi
88  else
89    diff "$out" "$optout" > /dev/null
90    if [ $? -ne 0 ] ; then
91      echo "Diff fails with these switches:"
92      echo $switches
93      echo "Differences:"
94      diff "$out" "$optout"
95      return 0;
96    fi
97  fi
98  return 1
99}
100
101for sw in $all_switches ; do
102  switches="$switches $sw"
103  if tryit "$switches" ; then
104    break;
105  fi
106done
107
108final=""
109while [ ! -z "$switches" ] ; do
110  trimmed=`echo "$switches" | sed -e 's/^ *\(-[^ ]*\).*/\1/'`
111  switches=`echo "$switches" | sed -e 's/^ *-[^ ]* *//'`
112  echo "Trimmed $trimmed from left"
113  tryit "$final $switches"
114  if [ "$?" -eq "0" ] ; then
115    echo "Still Failing .. continuing ..."
116    continue
117  else
118    echo "Found required early pass: $trimmed"
119    final="$final $trimmed"
120    continue
121  fi
122  echo "Next Loop"
123done
124
125if [ "$final" == " $all_switches" ] ; then
126  echo "findmisopt: Can't find a set of optimizations that make it fail"
127  exit 0
128fi
129echo "Smallest Optimization list=$final"
130bpcmd="bugpoint -run-llc --output "$out" --input /dev/null $bcfile $final --args $args"
131
132echo "Running: $bpcmd"
133$bpcmd
134echo "findmisopt finished."
135