1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
| #!/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: $optprog"
# Define the list of optimizations to run. This comprises the same set of
# optimizations that opt -O3 runs, in the same order.
opt_switches=`llvm-as < /dev/null -o - | opt -O3 -disable-output -debug-pass=Arguments 2>&1 | sed 's/Pass Arguments: //'`
all_switches="$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."
|