1#!/usr/bin/env perl 2# SPDX-License-Identifier: GPL-2.0 3 4# Read two files produced by the stackusage script, and show the 5# delta between them. 6# 7# Currently, only shows changes for functions listed in both files. We 8# could add an option to show also functions which have vanished or 9# appeared (which would often be due to gcc making other inlining 10# decisions). 11# 12# Another possible option would be a minimum absolute value for the 13# delta. 14# 15# A third possibility is for sorting by delta, but that can be 16# achieved by piping to sort -k5,5g. 17 18sub read_stack_usage_file { 19 my %su; 20 my $f = shift; 21 open(my $fh, '<', $f) 22 or die "cannot open $f: $!"; 23 while (<$fh>) { 24 chomp; 25 my ($file, $func, $size, $type) = split; 26 # Old versions of gcc (at least 4.7) have an annoying quirk in 27 # that a (static) function whose name has been changed into 28 # for example ext4_find_unwritten_pgoff.isra.11 will show up 29 # in the .su file with a name of just "11". Since such a 30 # numeric suffix is likely to change across different 31 # commits/compilers/.configs or whatever else we're trying to 32 # tweak, we can't really track those functions, so we just 33 # silently skip them. 34 # 35 # Newer gcc (at least 5.0) report the full name, so again, 36 # since the suffix is likely to change, we strip it. 37 next if $func =~ m/^[0-9]+$/; 38 $func =~ s/\..*$//; 39 # Line numbers are likely to change; strip those. 40 $file =~ s/:[0-9]+$//; 41 $su{"${file}\t${func}"} = {size => $size, type => $type}; 42 } 43 close($fh); 44 return \%su; 45} 46 47@ARGV == 2 48 or die "usage: $0 <old> <new>"; 49 50my $old = read_stack_usage_file($ARGV[0]); 51my $new = read_stack_usage_file($ARGV[1]); 52my @common = sort grep {exists $new->{$_}} keys %$old; 53for (@common) { 54 my $x = $old->{$_}{size}; 55 my $y = $new->{$_}{size}; 56 my $delta = $y - $x; 57 if ($delta) { 58 printf "%s\t%d\t%d\t%+d\n", $_, $x, $y, $delta; 59 } 60} 61