#!/usr/bin/env perl
# SPDX-License-Identifier: GPL-2.0
# Read two files produced by the stackusage script,
and show the
# delta between them.
java.lang.NullPointerException
# Currently, only shows changes
for functions listed in both files. We
# could add an option to show also functions which have vanished
or
# appeared (which would often be due to gcc making other inlining
# decisions).
java.lang.NullPointerException
# Another possible option would be a minimum absolute value
for the
# delta.
java.lang.NullPointerException
# A third possibility is
for sorting by delta, but that can be
# achieved by piping to sort -k5,5g.
sub read_stack_usage_file {
my %su;
my $f = shift;
open(my $fh,
'<', $f)
or die
"cannot open $f: $!";
while (<$fh>) {
chomp;
my ($file, $func, $size, $type) = split;
# Old versions of gcc (at least 4.7) have an annoying quirk in
# that a (
static) function whose name has been changed into
# for example ext4_find_unwritten_pgoff.isra.11 will show up
# in the .su file with a name of just
"11". Since such a
# numeric suffix is likely to change across different
# commits/compilers/.configs
or whatever
else we
're trying to
# tweak, we can
't really track those functions, so we just
# silently skip them.
java.lang.NullPointerException
# Newer gcc (at least 5.0) report the full name, so again,
# since the suffix is likely to change, we strip it.
next
if $func =~ m/^[0-9]+$/;
$func =~ s/\..*$
//;
# Line numbers are likely to change; strip those.
$file =~ s/:[0-9]+$
//;
$su{
"${file}\t${func}"} = {size => $size, type => $type};
}
close($fh);
return \%su;
}
@ARGV == 2
or die
"usage: $0 ";
my $old = read_stack_usage_file($ARGV[0]);
my $
new = read_stack_usage_file($ARGV[1]);
my @common = sort grep {exists $new->{$_}} keys %$old;
for (@common) {
my $x = $old->{$_}{size};
my $y = $new->{$_}{size};
my $delta = $y - $x;
if ($delta) {
printf
"%s\t%d\t%d\t%+d\n", $_, $x, $y, $delta;
}
}
