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#!/bin/bash
#
# findmisopt
#
# This is a quick and dirty hack to potentially find a misoptimization
# problem. Mostly its to work around problems in bugpoint that prevent
# it from finding a problem unless the set of failing optimizations are
# known and given to it on the command line.
#
# Given a bitcode file that produces correct output (or return code),
# this script will run through all the optimizations passes that gccas
# uses (in the same order) and will narrow down which optimizations
# cause the program either generate different output or return a
# different result code. When the passes have been narrowed down,
# bugpoint is invoked to further refine the problem to its origin. If a
# release version of bugpoint is available it will be used, otherwise
# debug.
#
# Usage:
# findmisopt bcfile outdir progargs [match]
#
# Where:
# bcfile
# is the bitcode file input (the unoptimized working case)
# outdir
# is a directory into which intermediate results are placed
# progargs
# is a single argument containing all the arguments the program needs
# proginput
# is a file name from which stdin should be directed
# match
# if specified to any value causes the result code of the program to
# be used to determine success/fail. If not specified success/fail is
# determined by diffing the program's output with the non-optimized
# output.
#
if [ "$#" -lt 3 ] ; then
echo "usage: findmisopt bcfile outdir progargs [match]"
exit 1
fi
dir="${0%%/utils/findmisopt}"
if [ -x "$dir/Release/bin/bugpoint" ] ; then
bugpoint="$dir/Release/bin/bugpoint"
elif [ -x "$dir/Debug/bin/bugpoint" ] ; then
bugpoint="$dir/Debug/bin/bugpoint"
else
echo "findmisopt: bugpoint not found"
exit 1
fi
bcfile="$1"
outdir="$2"
args="$3"
input="$4"
if [ ! -f "$input" ] ; then
input="/dev/null"
fi
match="$5"
name=`basename $bcfile .bc`
ll="$outdir/${name}.ll"
s="$outdir/${name}.s"
prog="$outdir/${name}"
out="$outdir/${name}.out"
optbc="$outdir/${name}.opt.bc"
optll="$outdir/${name}.opt.ll"
opts="$outdir/${name}.opt.s"
optprog="$outdir/${name}.opt"
optout="$outdir/${name}.opt.out"
ldflags="-lstdc++ -lm -ldl -lc"
echo "Test Name: $name"
echo "Unoptimized program: $prog"
echo " Optimized program: $optprog"
# Define the list of optimizations to run. This comprises the same set of
# optimizations that opt -std-compile-opts and gccld run, in the same order.
opt_switches=`llvm-as < /dev/null -o - | opt -std-compile-opts -disable-output -debug-pass=Arguments 2>&1 | sed 's/Pass Arguments: //'`
all_switches="$opt_switches"
echo "Passes : $all_switches"
# Create output directory if it doesn't exist
if [ -f "$outdir" ] ; then
echo "$outdir is not a directory"
exit 1
fi
if [ ! -d "$outdir" ] ; then
mkdir "$outdir" || exit 1
fi
# Generate the disassembly
llvm-dis "$bcfile" -o "$ll" -f || exit 1
# Generate the non-optimized program and its output
llc "$bcfile" -o "$s" -f || exit 1
gcc "$s" -o "$prog" $ldflags || exit 1
"$prog" $args > "$out" 2>&1 <$input
ex1=$?
# Current set of switches is empty
function tryit {
switches_to_use="$1"
opt $switches_to_use "$bcfile" -o "$optbc" -f || exit
llvm-dis "$optbc" -o "$optll" -f || exit
llc "$optbc" -o "$opts" -f || exit
gcc "$opts" -o "$optprog" $ldflags || exit
"$optprog" $args > "$optout" 2>&1 <"$input"
ex2=$?
if [ -n "$match" ] ; then
if [ "$ex1" -ne "$ex2" ] ; then
echo "Return code not the same with these switches:"
echo $switches
echo "Unoptimized returned: $ex1"
echo "Optimized returned: $ex2"
return 0
fi
else
diff "$out" "$optout" > /dev/null
if [ $? -ne 0 ] ; then
echo "Diff fails with these switches:"
echo $switches
echo "Differences:"
diff "$out" "$optout" | head
return 0;
fi
fi
return 1
}
echo "Trying to find optimization that breaks program:"
for sw in $all_switches ; do
echo -n " $sw"
switches="$switches $sw"
if tryit "$switches" ; then
break;
fi
done
# Terminate the previous output with a newline
echo ""
# Determine if we're done because none of the optimizations broke the program
if [ "$switches" == " $all_switches" ] ; then
echo "The program did not miscompile"
exit 0
fi
final=""
while [ ! -z "$switches" ] ; do
trimmed=`echo "$switches" | sed -e 's/^ *\(-[^ ]*\).*/\1/'`
switches=`echo "$switches" | sed -e 's/^ *-[^ ]* *//'`
echo "Trimmed $trimmed from left"
tryit "$final $switches"
if [ "$?" -eq "0" ] ; then
echo "Still Failing .. continuing ..."
continue
else
echo "Found required early pass: $trimmed"
final="$final $trimmed"
continue
fi
echo "Next Loop"
done
if [ "$final" == " $all_switches" ] ; then
echo "findmisopt: All optimizations pass. Perhaps this isn't a misopt?"
exit 0
fi
echo "Smallest Optimization list=$final"
bpcmd="$bugpoint -run-llc -disable-loop-extraction --output "$out" --input /dev/null $bcfile $final --args $args"
echo "Running: $bpcmd"
$bpcmd
echo "findmisopt finished."