Tools/Scripts/detect-mismatched-virtual-const

#!/usr/bin/perl -w

# Copyright (C) 2008 Apple Inc.  All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions
# are met:
#
# 1.  Redistributions of source code must retain the above copyright
#     notice, this list of conditions and the following disclaimer. 
# 2.  Redistributions in binary form must reproduce the above copyright
#     notice, this list of conditions and the following disclaimer in the
#     documentation and/or other materials provided with the distribution. 
# 3.  Neither the name of Apple Computer, Inc. ("Apple") nor the names of
#     its contributors may be used to endorse or promote products derived
#     from this software without specific prior written permission. 
#
# THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
# EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
# WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
# DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
# DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
# (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
# LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
# ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
# THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

#
# This script attempts to find instances of a problem where the signatures
# of virtual methods fail to match because one is defined 'const', and another
# is not. For example:
#       virtual void Base::doStuff() const;
#       virtual void Derived::doStuff();
#
# The lack of 'const' on the derived class gives it a different signature, and
# it will therefore not be called when doStuff() is called on a derived object
# via a base class pointer.
#
# Limitations of this script:
# * It only works on things in the WebCore namespace
# * Not all templatized methods may be found correctly
# * It doesn't know anything about inheritance, or if methods are actually virtual
# * It has lots of false positives (should add a whitelist for known-good signatures,
#    and specific methods)
# * It's rather slow
#
# Added by Simon Fraser <simon.fraser@apple.com>
#
# Run the script like this:
#  WebKitTools/Scripts/detect-mismatched-virtual-const WebKitBuild/Debug/WebCore.framework/WebCore
#
# Output consists of a series of warnings like this:
#
# Both const and non-const versions of bgColor():
#     HTMLDocument::bgColor()
#     HTMLBodyElement::bgColor() const
#     HTMLTableElement::bgColor() const
#     HTMLTableRowElement::bgColor() const
#     HTMLTableCellElement::bgColor() const
#

use strict;
no warnings qw /syntax/;


my $file = $ARGV[0];

print "Looking for unmatched const methods in $file\n";

if (!open NM, "(nm '$file' | c++filt | sed 's/^/STDOUT:/') 2>&1 |") {
    die "Could not open $file\n";
}

my $nestedParens;
   $nestedParens = qr /
                      [(]
                      [^()]*
                        (?:
                          (??{ $nestedParens })
                          [^()]*
                        )*
                      [)]/x;

my $nestedAngleBrackets;
   $nestedAngleBrackets = qr /
                      [<]
                      [^<>]*
                        (?:
                          (??{ $nestedAngleBrackets })
                          [^<>]*
                        )*
                      [>]/x;

my $bal;
   $bal = qr /([^:]+
              (??{ $nestedAngleBrackets })?
              (??{ $nestedParens }))
              ([^()]*)$/x;

my %signature_map = ();

while (<NM>) {
  my $line = $_;
  chomp($line);
  if ($line =~ m/ [tT] WebCore::(.+)$/) {
    my $method = $1;
    
    if ($method =~ /$bal/) {
      my $signature = $1;
      my $const = $2 eq " const";
      
      my $class = substr($method, 0, length($method) - length($signature) - ($const ? 6 : 0));

#      print "line: $line\nclass: $class\nmethod: $method\nsignature: $signature\nconst: $const\n\n";

      my %method_info = (
          'class' => $class,
          'const' => $const,
          'method' => $method,
      );
      
      push @{$signature_map{$signature}}, \%method_info;
    } else {
      print "unmatched line $method\n\n"
    }
  }
}
close NM;

my $sig;
for $sig (keys %signature_map) {
  #print "\n$sig\n";

  my @entries = @{$signature_map{$sig}};
#  print "$#entries\n";
  
  my $num_const = 0;
  my $num_not_const = 0;
  my $i;
  for $i (0 .. $#entries) {
    my $entry = @entries[$i];

    my $class = $entry->{'class'};
    my $const = $entry->{'const'};
    
    if ($const) {
      $num_const++;
    } else {
      $num_not_const++;
    }
  }

  if ($#entries > 1 && $num_const > 0 && $num_not_const > 0) {
    print "Both const and non-const versions of $sig:\n";

    for $i (0 .. $#entries) {
      my $entry = @entries[$i];
      my $method = $entry->{'method'};
      print "\t$method\n";
    }

  }
}