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Reid Spencer33c96832006-12-11 17:42:12 +00001#!/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#
Duncan Sands18d52f22010-09-29 20:09:55 +000017# The script takes two bitcode files, one from each build. They are
Reid Spencer33c96832006-12-11 17:42:12 +000018# 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
Reid Spencerb1788a32006-12-18 00:37:37 +000024# 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.
Reid Spencer33c96832006-12-11 17:42:12 +000027#
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
Duncan Sands18d52f22010-09-29 20:09:55 +000042# is the bitcode file for the first llvm environment
Reid Spencer33c96832006-12-11 17:42:12 +000043# bc2
Duncan Sands18d52f22010-09-29 20:09:55 +000044# is the bitcode file for the second llvm environment
Reid Spencer33c96832006-12-11 17:42:12 +000045# 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
Reid Spencerb1788a32006-12-18 00:37:37 +000055filt2=$6
Reid Spencer33c96832006-12-11 17:42:12 +000056if [ -z "$filt1" ] ; then
57 filt1="cat"
58fi
Reid Spencer33c96832006-12-11 17:42:12 +000059if [ -z "$filt2" ] ; then
60 filt2="cat"
61fi
Reid Spencerb1788a32006-12-18 00:37:37 +000062opt1="${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"
Reid Spencer33c96832006-12-11 17:42:12 +000072
Victor Hernandez66284e02009-10-24 04:23:03 +000073all_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"
Reid Spencer33c96832006-12-11 17:42:12 +000074
Reid Spencerb1788a32006-12-18 00:37:37 +000075#counter=0
Reid Spencer33c96832006-12-11 17:42:12 +000076function tryit {
77 switches_to_use="$1"
Reid Spencerb1788a32006-12-18 00:37:37 +000078 $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
Reid Spencer33c96832006-12-11 17:42:12 +000082 if [ $? -ne 0 ] ; then
83 echo
84 echo "Diff fails with these switches:"
85 echo $switches
86 echo "Differences:"
Reid Spencerb1788a32006-12-18 00:37:37 +000087 head $diffs
88 echo 'Switches:' $switches_to_use >> $diffs
89 else
90 rm $diffs
Reid Spencer33c96832006-12-11 17:42:12 +000091 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