1#! /usr/bin/env perl
2
3# Copyright (c) 2003 The Regents of The University of Michigan
4# All rights reserved.
5#
6# Redistribution and use in source and binary forms, with or without
7# modification, are permitted provided that the following conditions are
8# met: redistributions of source code must retain the above copyright
9# notice, this list of conditions and the following disclaimer;
10# redistributions in binary form must reproduce the above copyright
11# notice, this list of conditions and the following disclaimer in the
12# documentation and/or other materials provided with the distribution;
13# neither the name of the copyright holders nor the names of its
14# contributors may be used to endorse or promote products derived from
15# this software without specific prior written permission.
16#
17# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
18# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
19# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
20# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
21# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
22# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
23# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
24# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
25# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
26# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
27# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28#
29# Authors: Nathan Binkert
30# Steve Reinhardt
31
32# Diff two streams.
33#
34# Unlike regular diff, this script does not read in the entire input
35# before doing a diff, so it can be used on lengthy outputs piped from
36# other programs (e.g., M5 traces). The best way to do this is to
37# take advantage of the power of Perl's open function, which will
38# automatically fork a subprocess if the last character in the
39# "filename" is a pipe (|). Thus to compare the instruction traces
40# from two versions of m5 (m5a and m5b), you can do this:
41#
42# rundiff 'm5a --traceflags=InstExec |' 'm5b --traceflags=InstExec |'
43#
44
45use strict;
46use FileHandle;
47use Getopt::Std;
48
49#
50# Options:
51# -c <n> : print n lines of context before & after changes
52# -l <n> : use n lines of lookahead
53# -x : use "complex" diff from Algorithm::Diff (see below)
54#
55our ($opt_c, $opt_l, $opt_x);
56getopts('c:l:x');
57
58#
59# For the highest-quality (minimal) diffs, we can use the
60# Algorithm::Diff package. By default, a built-in, simple, and
61# generally quite adequate algorithm will be used. If you have
62# Algorithm::Diff installed on your system, and don't mind having the
63# script go slower (like 3-4x slower, based on informal observation),
64# then specify '-x' on the command line to use it.
65my $use_complexdiff = defined($opt_x);
66
67if ($use_complexdiff) {
68 # Don't use 'use', as that's a compile-time option and will fail
69 # on systems that don't have Algorithm::Diff installed even if
70 # $use_complexdiff is false. 'require' is evaluated at runtime,
71 # so it's OK.
72 require Algorithm::Diff;
73 import Algorithm::Diff qw(traverse_sequences);
74};
75
76my $lookahead_lines = $opt_l || 200;
77
78# in theory you could have different amounts of context before and
79# after a diff, but until someone needs that there's only one arg to
80# set both.
81my $precontext_lines = $opt_c || 3;
82my $postcontext_lines = $precontext_lines;
83
84my $file1 = $ARGV[0];
85my $file2 = $ARGV[1];
86
87die "Need two args." if (!(defined($file1) && defined($file2)));
88
89my ($fh1, $fh2);
90open($fh1, $file1) or die "Can't open $file1";
91open($fh2, $file2) or die "Can't open $file2";
92
93# print files to output so we know which is which
94print "-$file1\n";
95print "+$file2\n";
96
97# buffer of matching lines for pre-diff context
98my @precontext = ();
99# number of post-diff matching lines remaining to print
100my $postcontext = 0;
101
102# lookahead buffers for $file1 and $file2 respectively
103my @lines1 = ();
104my @lines2 = ();
105
106# Next line number available to print from each file. Generally this
107# corresponds to the oldest line in @precontext, or the oldest line in
108# @lines1 and @lines2 if @precontext is empty.
109my $lineno1 = 1;
110my $lineno2 = 1;
111
112# Fill a lookahead buffer to $lookahead_lines lines (or until EOF).
113sub fill
114{
115 my ($fh, $array) = @_;
116
117 while (@$array < $lookahead_lines) {
118 my $line = <$fh>;
119 last if (!defined($line));
120 push @$array, $line;
121 }
122}
123
124# Print and delete n lines from front of given array with given prefix.
125sub printlines
126{
127 my ($array, $n, $prefix) = @_;
128
129 while ($n--) {
130 my $line = shift @$array;
131 last if (!defined($line));
132 print $prefix, $line;
133 }
134}
135
136# Print a difference region where n1 lines of file1 were replaced by
137# n2 lines of file2 (where either n1 or n2 could be zero).
138sub printdiff
139{
140 my ($n1, $n2)= @_;
141
142 # If the precontext buffer is full or we're at the beginning of a
143 # file, then this is a new diff region, so we should print a
144 # header indicating the current line numbers. If we're past the
145 # beginning and the precontext buffer isn't full, then whatever
146 # we're about to print is contiguous with the end of the last
147 # region we printed, so we just concatenate them on the output.
148 if (@precontext == $precontext_lines || ($lineno1 == 0 && $lineno2 == 0)) {
149 print "@@ -$lineno1 +$lineno2 @@\n";
150 }
151
152 # Print and clear the precontext buffer.
153 if (@precontext) {
154 print ' ', join(' ', @precontext);
155 $lineno1 += scalar(@precontext);
156 $lineno2 += scalar(@precontext);
157 @precontext = ();
158 }
159
160 # Print the differing lines.
161 printlines(\@lines1, $n1, '-');
162 printlines(\@lines2, $n2, '+');
163 $lineno1 += $n1;
164 $lineno2 += $n2;
165
166 # Set $postcontext to print the next $postcontext_lines matching lines.
167 $postcontext = $postcontext_lines;
168
| 1#! /usr/bin/env perl
2
3# Copyright (c) 2003 The Regents of The University of Michigan
4# All rights reserved.
5#
6# Redistribution and use in source and binary forms, with or without
7# modification, are permitted provided that the following conditions are
8# met: redistributions of source code must retain the above copyright
9# notice, this list of conditions and the following disclaimer;
10# redistributions in binary form must reproduce the above copyright
11# notice, this list of conditions and the following disclaimer in the
12# documentation and/or other materials provided with the distribution;
13# neither the name of the copyright holders nor the names of its
14# contributors may be used to endorse or promote products derived from
15# this software without specific prior written permission.
16#
17# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
18# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
19# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
20# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
21# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
22# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
23# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
24# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
25# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
26# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
27# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28#
29# Authors: Nathan Binkert
30# Steve Reinhardt
31
32# Diff two streams.
33#
34# Unlike regular diff, this script does not read in the entire input
35# before doing a diff, so it can be used on lengthy outputs piped from
36# other programs (e.g., M5 traces). The best way to do this is to
37# take advantage of the power of Perl's open function, which will
38# automatically fork a subprocess if the last character in the
39# "filename" is a pipe (|). Thus to compare the instruction traces
40# from two versions of m5 (m5a and m5b), you can do this:
41#
42# rundiff 'm5a --traceflags=InstExec |' 'm5b --traceflags=InstExec |'
43#
44
45use strict;
46use FileHandle;
47use Getopt::Std;
48
49#
50# Options:
51# -c <n> : print n lines of context before & after changes
52# -l <n> : use n lines of lookahead
53# -x : use "complex" diff from Algorithm::Diff (see below)
54#
55our ($opt_c, $opt_l, $opt_x);
56getopts('c:l:x');
57
58#
59# For the highest-quality (minimal) diffs, we can use the
60# Algorithm::Diff package. By default, a built-in, simple, and
61# generally quite adequate algorithm will be used. If you have
62# Algorithm::Diff installed on your system, and don't mind having the
63# script go slower (like 3-4x slower, based on informal observation),
64# then specify '-x' on the command line to use it.
65my $use_complexdiff = defined($opt_x);
66
67if ($use_complexdiff) {
68 # Don't use 'use', as that's a compile-time option and will fail
69 # on systems that don't have Algorithm::Diff installed even if
70 # $use_complexdiff is false. 'require' is evaluated at runtime,
71 # so it's OK.
72 require Algorithm::Diff;
73 import Algorithm::Diff qw(traverse_sequences);
74};
75
76my $lookahead_lines = $opt_l || 200;
77
78# in theory you could have different amounts of context before and
79# after a diff, but until someone needs that there's only one arg to
80# set both.
81my $precontext_lines = $opt_c || 3;
82my $postcontext_lines = $precontext_lines;
83
84my $file1 = $ARGV[0];
85my $file2 = $ARGV[1];
86
87die "Need two args." if (!(defined($file1) && defined($file2)));
88
89my ($fh1, $fh2);
90open($fh1, $file1) or die "Can't open $file1";
91open($fh2, $file2) or die "Can't open $file2";
92
93# print files to output so we know which is which
94print "-$file1\n";
95print "+$file2\n";
96
97# buffer of matching lines for pre-diff context
98my @precontext = ();
99# number of post-diff matching lines remaining to print
100my $postcontext = 0;
101
102# lookahead buffers for $file1 and $file2 respectively
103my @lines1 = ();
104my @lines2 = ();
105
106# Next line number available to print from each file. Generally this
107# corresponds to the oldest line in @precontext, or the oldest line in
108# @lines1 and @lines2 if @precontext is empty.
109my $lineno1 = 1;
110my $lineno2 = 1;
111
112# Fill a lookahead buffer to $lookahead_lines lines (or until EOF).
113sub fill
114{
115 my ($fh, $array) = @_;
116
117 while (@$array < $lookahead_lines) {
118 my $line = <$fh>;
119 last if (!defined($line));
120 push @$array, $line;
121 }
122}
123
124# Print and delete n lines from front of given array with given prefix.
125sub printlines
126{
127 my ($array, $n, $prefix) = @_;
128
129 while ($n--) {
130 my $line = shift @$array;
131 last if (!defined($line));
132 print $prefix, $line;
133 }
134}
135
136# Print a difference region where n1 lines of file1 were replaced by
137# n2 lines of file2 (where either n1 or n2 could be zero).
138sub printdiff
139{
140 my ($n1, $n2)= @_;
141
142 # If the precontext buffer is full or we're at the beginning of a
143 # file, then this is a new diff region, so we should print a
144 # header indicating the current line numbers. If we're past the
145 # beginning and the precontext buffer isn't full, then whatever
146 # we're about to print is contiguous with the end of the last
147 # region we printed, so we just concatenate them on the output.
148 if (@precontext == $precontext_lines || ($lineno1 == 0 && $lineno2 == 0)) {
149 print "@@ -$lineno1 +$lineno2 @@\n";
150 }
151
152 # Print and clear the precontext buffer.
153 if (@precontext) {
154 print ' ', join(' ', @precontext);
155 $lineno1 += scalar(@precontext);
156 $lineno2 += scalar(@precontext);
157 @precontext = ();
158 }
159
160 # Print the differing lines.
161 printlines(\@lines1, $n1, '-');
162 printlines(\@lines2, $n2, '+');
163 $lineno1 += $n1;
164 $lineno2 += $n2;
165
166 # Set $postcontext to print the next $postcontext_lines matching lines.
167 $postcontext = $postcontext_lines;
168
|
170}
171
172
173########################
174#
175# Complex diff algorithm
176#
177########################
178
179{
180 my $match_found;
181 my $discard_lines1;
182 my $discard_lines2;
183
184 sub match { $match_found = 1; }
185 sub discard1 { $discard_lines1++ unless $match_found; }
186 sub discard2 { $discard_lines2++ unless $match_found; }
187
188 sub complex_diff
189 {
190 $match_found = 0;
191 $discard_lines1 = 0;
192 $discard_lines2 = 0;
193
194 # See Diff.pm. Note that even though this call generates a
195 # complete diff of both lookahead buffers, all we use it for
196 # is to figure out how many lines to discard off the front of
197 # each buffer to resync the streams.
198 traverse_sequences( \@lines1, \@lines2,
199 { MATCH => \&match,
200 DISCARD_A => \&discard1,
201 DISCARD_B => \&discard2 });
202
203 if (!$match_found) {
204 printdiff(scalar(@lines1), scalar(@lines2));
205 die "Lost sync!";
206 }
207
208 # Since we shouldn't get here unless the first lines of the
209 # buffers are different, then we must discard some lines off
210 # at least one of the buffers.
211 die if ($discard_lines1 == 0 && $discard_lines2 == 0);
212
213 printdiff($discard_lines1, $discard_lines2);
214 }
215}
216
217#######################
218#
219# Simple diff algorithm
220#
221#######################
222
223# Check for a pair of matching lines; if found, generate appropriate
224# diff output.
225sub checkmatch
226{
227 my ($n1, $n2) = @_;
228
229 # Check if two adjacent lines match, to reduce false resyncs
230 # (particularly on unrelated blank lines). This generates
231 # larger-than-necessary diffs when a single line really should be
232 # treated as common; if that bugs you, use Algorithm::Diff.
233 if ($lines1[$n1] eq $lines2[$n2] && $lines1[$n1+1] eq $lines2[$n2+1]) {
234 printdiff($n1, $n2);
235 return 1;
236 }
237
238 return 0;
239}
240
241sub simple_diff
242{
243 # Look for differences of $cnt lines to resync,
244 # increasing $cnt from 1 to $lookahead_lines until we find
245 # something.
246 for (my $cnt = 1; $cnt < $lookahead_lines-1; ++$cnt) {
247 # Check for n lines in one file being replaced by
248 # n lines in the other.
249 return if checkmatch($cnt, $cnt);
250 # Find differences where n lines in one file were
251 # replaced by m lines in the other. We let m = $cnt
252 # and iterate for n = 0 to $cnt-1.
253 for (my $n = 0; $n < $cnt; ++$n) {
254 return if checkmatch($n, $cnt);
255 return if checkmatch($cnt, $n);
256 }
257 }
258
259 printdiff(scalar(@lines1), scalar(@lines2));
260 die "Lost sync!";
261}
262
263# Set the pointer to the appropriate diff function.
264#
265# Note that in either case the function determines how many lines to
266# discard from the front of each lookahead buffer to resync the
267# streams, then prints the appropriate diff output and discards them.
268# After the function returns, it should always be the case that
269# $lines1[0] eq $lines2[0].
270my $find_diff = $use_complexdiff ? \&complex_diff : \&simple_diff;
271
272# The main loop.
273while (1) {
274 # keep lookahead buffers topped up
275 fill($fh1, \@lines1);
276 fill($fh2, \@lines2);
277
278 # peek at first line in each buffer
279 my $l1 = $lines1[0];
280 my $l2 = $lines2[0];
281
282 if (!defined($l1) && !defined($l2)) {
283 # reached EOF on both streams: exit
284 exit(1);
285 }
286
287 if ($l1 eq $l2) {
288 # matching lines: delete from lookahead buffer
289 shift @lines1;
290 shift @lines2;
291 # figure out what to do with this line
292 if ($postcontext > 0) {
293 # we're in the post-context of a diff: print it
| 174}
175
176
177########################
178#
179# Complex diff algorithm
180#
181########################
182
183{
184 my $match_found;
185 my $discard_lines1;
186 my $discard_lines2;
187
188 sub match { $match_found = 1; }
189 sub discard1 { $discard_lines1++ unless $match_found; }
190 sub discard2 { $discard_lines2++ unless $match_found; }
191
192 sub complex_diff
193 {
194 $match_found = 0;
195 $discard_lines1 = 0;
196 $discard_lines2 = 0;
197
198 # See Diff.pm. Note that even though this call generates a
199 # complete diff of both lookahead buffers, all we use it for
200 # is to figure out how many lines to discard off the front of
201 # each buffer to resync the streams.
202 traverse_sequences( \@lines1, \@lines2,
203 { MATCH => \&match,
204 DISCARD_A => \&discard1,
205 DISCARD_B => \&discard2 });
206
207 if (!$match_found) {
208 printdiff(scalar(@lines1), scalar(@lines2));
209 die "Lost sync!";
210 }
211
212 # Since we shouldn't get here unless the first lines of the
213 # buffers are different, then we must discard some lines off
214 # at least one of the buffers.
215 die if ($discard_lines1 == 0 && $discard_lines2 == 0);
216
217 printdiff($discard_lines1, $discard_lines2);
218 }
219}
220
221#######################
222#
223# Simple diff algorithm
224#
225#######################
226
227# Check for a pair of matching lines; if found, generate appropriate
228# diff output.
229sub checkmatch
230{
231 my ($n1, $n2) = @_;
232
233 # Check if two adjacent lines match, to reduce false resyncs
234 # (particularly on unrelated blank lines). This generates
235 # larger-than-necessary diffs when a single line really should be
236 # treated as common; if that bugs you, use Algorithm::Diff.
237 if ($lines1[$n1] eq $lines2[$n2] && $lines1[$n1+1] eq $lines2[$n2+1]) {
238 printdiff($n1, $n2);
239 return 1;
240 }
241
242 return 0;
243}
244
245sub simple_diff
246{
247 # Look for differences of $cnt lines to resync,
248 # increasing $cnt from 1 to $lookahead_lines until we find
249 # something.
250 for (my $cnt = 1; $cnt < $lookahead_lines-1; ++$cnt) {
251 # Check for n lines in one file being replaced by
252 # n lines in the other.
253 return if checkmatch($cnt, $cnt);
254 # Find differences where n lines in one file were
255 # replaced by m lines in the other. We let m = $cnt
256 # and iterate for n = 0 to $cnt-1.
257 for (my $n = 0; $n < $cnt; ++$n) {
258 return if checkmatch($n, $cnt);
259 return if checkmatch($cnt, $n);
260 }
261 }
262
263 printdiff(scalar(@lines1), scalar(@lines2));
264 die "Lost sync!";
265}
266
267# Set the pointer to the appropriate diff function.
268#
269# Note that in either case the function determines how many lines to
270# discard from the front of each lookahead buffer to resync the
271# streams, then prints the appropriate diff output and discards them.
272# After the function returns, it should always be the case that
273# $lines1[0] eq $lines2[0].
274my $find_diff = $use_complexdiff ? \&complex_diff : \&simple_diff;
275
276# The main loop.
277while (1) {
278 # keep lookahead buffers topped up
279 fill($fh1, \@lines1);
280 fill($fh2, \@lines2);
281
282 # peek at first line in each buffer
283 my $l1 = $lines1[0];
284 my $l2 = $lines2[0];
285
286 if (!defined($l1) && !defined($l2)) {
287 # reached EOF on both streams: exit
288 exit(1);
289 }
290
291 if ($l1 eq $l2) {
292 # matching lines: delete from lookahead buffer
293 shift @lines1;
294 shift @lines2;
295 # figure out what to do with this line
296 if ($postcontext > 0) {
297 # we're in the post-context of a diff: print it
|