[fnrec] Enhance function recording

Enhance the information collected by the function recorder to include
the call site and entry/exit counts.  This allows fnrec.pl to produce
a call tree such as:

    step (from core/getkey.c:46 = 0x17e90) {
      ref_increment (from core/process.c:93 = 0x73ec) { }
      net_step (from core/process.c:96 = 0x73f1) {
        net_poll (from net/netdevice.c:741 = 0xbce6) {
          netdev_poll (from net/netdevice.c:700 = 0xbc58) { }
          netdev_rx_dequeue (from net/netdevice.c:709 = 0xbc65) { }
        }
      }
      ref_decrement (from core/process.c:96 = 0x73f9) { }
    }

Note that inlined functions are reported, confusingly, as extra calls
to the *containing* function.  Minimise this confusion by adding the
attribute "no_instrument_function" to all functions declared as
inline.  (Static functions that have been inlined autonomously by gcc
will still be problematic, but these are far fewer in number.)

Signed-off-by: Michael Brown <mcb30@ipxe.org>

1 files changed, 145 insertions, 0 deletions

diff --git a/src/util/fnrec.pl b/src/util/fnrec.pl
new file mode 100755
index 00000000..9a2b3d81
--- /dev/null
+++ b/src/util/fnrec.pl
@@ -0,0 +1,145 @@
+#!/usr/bin/perl -w
+#
+# Copyright (C) 2010 Michael Brown <mbrown@fensystems.co.uk>.
+#
+# This program is free software; you can redistribute it and/or
+# modify it under the terms of the GNU General Public License as
+# published by the Free Software Foundation; either version 2 of the
+# License, or any later version.
+#
+# This program is distributed in the hope that it will be useful, but
+# WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+# General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+
+=head1 NAME
+
+fnrec.pl
+
+=head1 SYNOPSIS
+
+fnrec.pl [options] bin/image.xxx < logfile
+
+Decode a function trace produced by building with FNREC=1
+
+Options:
+
+	-m,--max-depth=N	Set maximum displayed function depth
+
+=cut
+
+use IPC::Open2;
+use Getopt::Long;
+use Pod::Usage;
+use strict;
+use warnings;
+
+use constant MAX_OPEN_BRACE => 10;
+use constant MAX_COMMON_BRACE => 3;
+use constant MAX_CLOSE_BRACE => 10;
+
+# Parse command-line options
+my $max_depth = 16;
+Getopt::Long::Configure ( 'bundling', 'auto_abbrev' );
+GetOptions (
+  'help|h' => sub { pod2usage ( 1 ); },
+  'max-depth|m=i' => sub { shift; $max_depth = shift; },
+) or die "Could not parse command-line options\n";
+pod2usage ( 1 ) unless @ARGV == 1;
+my $image = shift;
+my $elf = $image.".tmp";
+die "ELF file ".$elf." not found\n" unless -e $elf;
+
+# Start up addr2line
+my $addr2line_pid = open2 ( my $addr2line_out, my $addr2line_in,
+			    "addr2line", "-f", "-e", $elf )
+    or die "Could not start addr2line: $!\n";
+
+# Translate address using addr2line
+sub addr2line {
+  my $address = shift;
+
+  print $addr2line_in $address."\n";
+  chomp ( my $name = <$addr2line_out> );
+  chomp ( my $file_line = <$addr2line_out> );
+  ( my $file, my $line ) = ( $file_line =~ /^(.*):(\d+)$/ );
+  $file =~ s/^.*\/src\///;
+  my $location = ( $line ? $file.":".$line." = ".$address : $address );
+  return ( $name, $location );
+}
+
+# Parse logfile
+my $depth = 0;
+my $depths = [];
+while ( my $line = <> ) {
+  chomp $line;
+  $line =~ s/\r//g;
+  ( my $called_fn, my $call_site, my $entry_count, my $exit_count ) =
+      ( $line =~ /^(0x[0-9a-f]+)\s+(0x[0-9a-f]+)\s+([0-9]+)\s+([0-9]+)$/ )
+      or print $line."\n" and next;
+
+  ( my $called_fn_name, undef ) = addr2line ( $called_fn );
+  ( undef, my $call_site_location ) = addr2line ( $call_site );
+  $entry_count = ( $entry_count + 0 );
+  $exit_count = ( $exit_count + 0 );
+
+  if ( $entry_count >= $exit_count ) {
+    #
+    # Function entry
+    #
+    my $text = "";
+    $text .= $called_fn_name." (from ".$call_site_location.")";
+    if ( $exit_count <= MAX_COMMON_BRACE ) {
+      $text .= " { }" x $exit_count;
+    } else {
+      $text .= " { } x ".$exit_count;
+    }
+    $entry_count -= $exit_count;
+    if ( $entry_count <= MAX_OPEN_BRACE ) {
+      $text .= " {" x $entry_count;
+    } else {
+      $text .= " { x ".$entry_count;
+    }
+    my $indent = "  " x $depth;
+    print $indent.$text."\n";
+    $depth += $entry_count;
+    $depth = $max_depth if ( $depth > $max_depth );
+    push @$depths, ( { called_fn => $called_fn, call_site => $call_site } ) x
+	( $depth - @$depths );
+  } else {
+    #
+    # Function exit
+    #
+    my $text = "";
+    if ( $entry_count <= MAX_COMMON_BRACE ) {
+      $text .= " { }" x $entry_count;
+    } else {
+      $text .= " { } x ".$entry_count;
+    }
+    $exit_count -= $entry_count;
+    if ( $exit_count <= MAX_CLOSE_BRACE ) {
+      $text .= " }" x $exit_count;
+    } else {
+      $text .= " } x ".$exit_count;
+    }
+    $depth -= $exit_count;
+    $depth = 0 if ( $depth < 0 );
+    if ( ( @$depths == 0 ) ||
+	 ( $depths->[$depth]->{called_fn} ne $called_fn ) ||
+	 ( $depths->[$depth]->{call_site} ne $call_site ) ) {
+      $text .= " (from ".$called_fn_name." to ".$call_site_location.")";
+    }
+    splice ( @$depths, $depth );
+    my $indent = "  " x $depth;
+    print substr ( $indent.$text, 1 )."\n";
+  }
+}
+
+# Clean up addr2line
+close $addr2line_in;
+close $addr2line_out;
+waitpid ( $addr2line_pid, 0 );