Linux build: Use sysroot when calculating dependencies

third_party/dpkg-dev/scripts/Dpkg/Shlibs/Cppfilt.pm

+# Copyright © 2009-2010 Modestas Vainius <modax@debian.org>
+#
+# 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
+# (at your option) 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, see <https://www.gnu.org/licenses/>.
+
+package Dpkg::Shlibs::Cppfilt;
+
+use strict;
+use warnings;
+
+our $VERSION = '0.01';
+
+use Exporter qw(import);
+
+use Dpkg::ErrorHandling;
+use Dpkg::IPC;
+use IO::Handle;
+
+our @EXPORT = qw(cppfilt_demangle_cpp);
+our @EXPORT_OK = qw(cppfilt_demangle);
+
+# A hash of 'objects' referring to preforked c++filt processes for the distinct
+# demangling types.
+my %cppfilts;
+
+sub get_cppfilt {
+    my $type = shift || 'auto';
+
+    # Fork c++filt process for demangling $type unless it is forked already.
+    # Keeping c++filt running improves performance a lot.
+    my $filt;
+    if (exists $cppfilts{$type}) {
+        $filt = $cppfilts{$type};
+    } else {
+        $filt = { from => undef, to => undef,
+                    last_symbol => '', last_result => '' };
+        $filt->{pid} = spawn(exec => [ 'c++filt', "--format=$type" ],
+                             from_pipe => \$filt->{from},
+                             to_pipe => \$filt->{to});
+        syserr(_g('unable to execute %s'), 'c++filt')
+            unless defined $filt->{from};
+        $filt->{from}->autoflush(1);
+
+        $cppfilts{$type} = $filt;
+    }
+    return $filt;
+}
+
+# Demangle the given $symbol using demangler for the specified $type (defaults
+# to 'auto') . Extraneous characters trailing after a mangled name are kept
+# intact. If neither whole $symbol nor portion of it could be demangled, undef
+# is returned.
+sub cppfilt_demangle {
+    my ($symbol, $type) = @_;
+
+    # Start or get c++filt 'object' for the requested type.
+    my $filt = get_cppfilt($type);
+
+    # Remember the last result. Such a local optimization is cheap and useful
+    # when sequential pattern matching is performed.
+    if ($filt->{last_symbol} ne $symbol) {
+        # This write/read operation should not deadlock because c++filt flushes
+        # output buffer on LF or each invalid character.
+        print { $filt->{from} } $symbol, "\n";
+        my $demangled = readline($filt->{to});
+        chop $demangled;
+
+        # If the symbol was not demangled, return undef
+        $demangled = undef if $symbol eq $demangled;
+
+        # Remember the last result
+        $filt->{last_symbol} = $symbol;
+        $filt->{last_result} = $demangled;
+    }
+    return $filt->{last_result};
+}
+
+sub cppfilt_demangle_cpp {
+    my $symbol = shift;
+    return cppfilt_demangle($symbol, 'auto');
+}
+
+sub terminate_cppfilts {
+    foreach (keys %cppfilts) {
+        next if not defined $cppfilts{$_}{pid};
+        close $cppfilts{$_}{from};
+        close $cppfilts{$_}{to};
+        wait_child($cppfilts{$_}{pid}, cmdline => 'c++filt',
+                                       nocheck => 1,
+                                       timeout => 5);
+        delete $cppfilts{$_};
+    }
+}
+
+# Close/terminate running c++filt process(es)
+END {
+    # Make sure exitcode is not changed (by wait_child)
+    my $exitcode = $?;
+    terminate_cppfilts();
+    $? = $exitcode;
+}
+
+1;