Add `szcmp` script for comparing sizes of files
Change-Id: I2017b0f1e746e191f0a5de1f047dec8ba19dd395
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/238384
Reviewed-by: Sigmund Cherem <sigmund@google.com>
Commit-Queue: Stephen Adams <sra@google.com>
diff --git a/pkg/compiler/tool/szcmp b/pkg/compiler/tool/szcmp
new file mode 100755
index 0000000..1b2db57
--- /dev/null
+++ b/pkg/compiler/tool/szcmp
@@ -0,0 +1,82 @@
+#!/bin/bash
+# Copyright (c) 2022, the Dart project authors. Please see the AUTHORS file
+# for details. All rights reserved. Use of this source code is governed by a
+# BSD-style license that can be found in the LICENSE file.
+#
+# Usage: szcmp files
+#
+# Compare sizes of files as percentages in a table. Column header is the
+# baseline (i.e. all sizes in the column are in terms of the file in the column
+# header).
+#
+# Example with dart2js workflow:
+#
+# $ dart2js ... --out=v1/m.js
+# # change dart2js
+# $ dart2js ... --out=v2/m.js
+# # change dart2js again
+# $ dart2js ... --out=v3/m.js
+#
+# $ szcmp v?/m.js
+# v1/m.js v2/m.js v3/m.js
+# 5793879 v1/m.js = -4.499% +4.461%
+# 6066812 v2/m.js +4.711% = +9.382%
+# 5546433 v3/m.js -4.271% -8.577% =
+#
+# The first column of the matrix is usually the most relevant - `v2` is 4.7%
+# larger than `v1` and `v3` is 4.2% smaller than `v1`. The other columns can be
+# useful for understanding the differential changes. Sizes relative to `v2` are
+# in the next column, e.g. the step from `v2` to `v3` was a reduction of
+# 8.6%. Above-diagonal values show the percentage change in the 'undo'
+# direction. While changing from `v2` to `v3` reduces by 8.6%, reverting that
+# change would be an increase of 9.4%.
+
+wc -c "$@" |
+awk '
+$2 == "total" { next; }
+
+{
+ N++
+ r[N,0] = $1;
+ r[N,1] = $2;
+}
+
+END {
+ r[0,0] = "" # header col 0
+ r[0,1] = "" # header col 1
+
+ for (i = 1; i <= N; i++) { #skips "total" line
+ r[0, i+1] = r[i,1] # name header
+
+ for (j = 1; j <= N; j++) {
+ s1 = r[i,0]
+ s2 = r[j,0];
+ if (s1 == s2) {
+ r[i, j+1] = "="
+ } else {
+ x = sprintf("%.3f%%", (s1 - s2) / s2 * 100)
+ if (s1 > s2) x = "+" x
+ r[i, j+1] = x
+ }
+ }
+ }
+
+ # find column widths
+ for (cc = 0; cc <= N+1; cc++) {
+ w[cc] = 0;
+ for (rr = 0; rr <= N; rr++) {
+ if (length(r[rr,cc]) > w[cc]) w[cc] = length(r[rr,cc])
+ }
+ }
+
+ for (rr = 0; rr <= N; rr++) {
+ line = ""
+ sep = ""
+ for (cc = 0; cc <= N+1; cc++) {
+ line = line sep sprintf("%*s", w[cc], r[rr, cc])
+ sep = " "
+ }
+ print line
+ }
+}
+'
