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#!/usr/bin/perl -w

# This script takes two arguments, a version script and a dynamic library

# (in that order), and prints a list of symbols to be exported from the

# library.

# It expects a 'nm' with the POSIX '-P' option, but everyone has one of

# those, right?  It also expects that symbol names have a leading underscore,

# which is somewhat less likely.

use File::Glob ':glob';

use FileHandle;

use IPC::Open2;

# The glob patterns that are to be applied to the demangled name

my @cxx_globs = ();

# The glob patterns that apply directly to the name in the .o files

my @globs = ();

# The patterns for local variables (usually just '*').

my @ignored = ();

##########

# Fill in the various glob arrays.

# The next pattern will go into this array.

my $glob = \@globs;

my $symvers = shift;

open F,$symvers or die $!;

while (<F>) {

    chomp;

    # Lines of the form '} SOME_VERSION_NAME_1.0;'

    if (/^[ \t]*\}[ \tA-Z0-9_.a-z]*;[ \t]*$/) {

      $glob = \@globs;

      next;

    }

    # Comment and blank lines

    next if (/^[ \t]*\#/);

    next if (/^[ \t]*$/);

    # Lines of the form 'SOME_VERSION_NAME_1.1 {'

    next if (/^[A-Z0-9_. \t]*{$/);

    # Ignore 'global:'

    next if (/^[ \t]*global:$/);

    # After 'local:', globs should be ignored, they won't be exported.

    if (/^[ \t]*local:$/) {

        $glob = \@ignored;

        next;

    }

    # After 'extern "C++"', globs are C++ patterns

    if (/^[ \t]*extern \"C\+\+\"[ \t]*$/) {

        $glob = \@cxx_globs;

        next;

    }

    # Catch globs.  Note that '{}' is not allowed in globs by this script,

    # so only '*' and '[]' are available.

    if (/^[ \t]*([^ \t;{}#]+);?[ \t]*$/) {

        my $ptn = $1;

        # Turn the glob into a regex by replacing '*' with '.*'.

        $ptn =~ s/\*/\.\*/g;

        push @$glob,$ptn;

        next;

    }

    # Important sanity check.  This script can't handle lots of formats

    # that GNU ld can, so be sure to error out if one is seen!

    die "strange line `$_'";

}

close F;

# Make 'if (1)' for debugging.

if (0) {

    print "cxx:\n";

    (printf "%s\n",$_) foreach (@cxx_globs);

    print "globs:\n";

    (printf "%s\n", $_) foreach (@globs);

    print "ignored:\n";

    (printf "%s\n", $_) foreach (@ignored);

}

##########

# Combine the arrays into single regular expressions

# This cuts the time required from about 30 seconds to about 0.5 seconds.

my $glob_regex = '^_(' . (join '|',@globs) . ')$';

my $cxx_regex = (join '|',@cxx_globs);

##########

# Get all the symbols from the library, match them, and add them to a hash.

my %export_hash = ();

my $nm = $ENV{'NM_FOR_TARGET'} || "nm";

# Process each symbol.

print STDERR $nm.' -P '.(join ' ',@ARGV).'|';

open NM,$nm.' -P '.(join ' ',@ARGV).'|' or die $!;

# Talk to c++filt through a pair of file descriptors.

open2(*FILTIN, *FILTOUT, "c++filt --strip-underscores") or die $!;

NAME: while (<NM>) {

    my $i;

    chomp;

    # nm prints out stuff at the start, ignore it.

    next if (/^$/);

    next if (/:$/);

    # Ignore undefined and local symbols.

    next if (/^([^ ]+) [Ua-z] /);

    # $sym is the name of the symbol, $noeh_sym is the same thing with

    # any '.eh' suffix removed.

    die "unknown nm output $_" if (! /^([^ ]+) [A-Z] /);

    my $sym = $1;

    my $noeh_sym = $sym;

    $noeh_sym =~ s/\.eh$//;

    # Maybe it matches one of the patterns based on the symbol in the .o file.

    if ($noeh_sym =~ /$glob_regex/) {

        $export_hash{$sym} = 1;

        next NAME;

    }

    # No?  Well, maybe its demangled form matches one of those patterns.

    printf FILTOUT "%s\n",$noeh_sym;

    my $dem = <FILTIN>;

    chomp $dem;

    if ($dem =~ /$cxx_regex/) {

        $export_hash{$sym} = 2;

        next NAME;

    }

    # No?  Well, then ignore it.

}

close NM or die "nm error";

close FILTOUT or die "c++filt error";

close FILTIN or die "c++filt error";

##########

# Print out the export file

# Print information about generating this file

print "# This is a generated file.\n";

print "# It was generated by:\n";

printf "# %s %s %s\n", $0, $symvers, (join ' ',@ARGV);

foreach my $i (keys %export_hash) {

  printf "%s\n",$i or die;

}