| From 59477dae6f2c68f0ebd9ccca18e737b67408bc11 Mon Sep 17 00:00:00 2001 |
| From: Tom Anderson <thomasanderson@chromium.org> |
| Date: Wed, 8 Jan 2020 10:55:20 -0800 |
| Subject: [PATCH 1/2] dkpg-shlibdeps: Add option to ignore weak undefined |
| symbols |
| |
| Weak undefined symbols can be used to test feature support. For example: |
| |
| __attribute__((weak)) uint64_t gbm_bo_get_modifier(struct gbm_bo* bo); |
| void foo(gbm_bo* bo) { |
| // gbm_create_device is a strong undefined symbol. The dynamic linker will |
| // fail if this is not available. |
| gbm_create_device(1234); |
| // gbm_bo_get_modifier is a weak undefined symbol. It will be NULL if it's |
| // not available. |
| if (gbm_bo_get_modifier) |
| gbm_bo_get_modifier(bo); |
| } |
| |
| However currently, dpkg-shlibdeps would consider gbm_bo_get_modifier in the |
| example to be a required symbol (and would increase the minimum required library |
| version), even though the intention is to use it only if it is available. |
| |
| To address this, this change skips weak undefined symbols when checking for |
| dependencies. Out of an abundance of caution, this behavior is guarded behind a |
| new flag: --ignore-weak-undefined. |
| --- |
| scripts/dpkg-shlibdeps.pl | 6 ++++++ |
| 1 file changed, 6 insertions(+) |
| |
| diff --git a/scripts/dpkg-shlibdeps.pl b/scripts/dpkg-shlibdeps.pl |
| index 8142c85b4..e3d8c7200 100755 |
| --- a/scripts/dpkg-shlibdeps.pl |
| +++ b/scripts/dpkg-shlibdeps.pl |
| @@ -67,6 +67,7 @@ my $varlistfile = 'debian/substvars'; |
| my $varlistfilenew; |
| my $varnameprefix = 'shlibs'; |
| my $ignore_missing_info = 0; |
| +my $ignore_weak_undefined = 0; |
| my $warnings = WARN_SYM_NOT_FOUND | WARN_DEP_AVOIDABLE; |
| my $debug = 0; |
| my @exclude = (); |
| @@ -120,6 +121,8 @@ foreach (@ARGV) { |
| } |
| } elsif (m/^--ignore-missing-info$/) { |
| $ignore_missing_info = 1; |
| + } elsif (m/^--ignore-weak-undefined$/) { |
| + $ignore_weak_undefined = 1; |
| } elsif (m/^--warnings=(\d+)$/) { |
| $warnings = $1; |
| } elsif (m/^-t(.*)$/) { |
| @@ -365,6 +368,7 @@ foreach my $file (keys %exec) { |
| } |
| debug(2, 'Analyzing all undefined symbols'); |
| foreach my $sym ($obj->get_undefined_dynamic_symbols()) { |
| + next if $ignore_weak_undefined && $sym->{weak}; |
| my $name = $sym->{name}; |
| if ($sym->{version}) { |
| $name .= '@' . "$sym->{version}"; |
| @@ -610,6 +614,8 @@ sub usage { |
| in the given build directory. |
| -v enable verbose mode (can be used multiple times). |
| --ignore-missing-info don't fail if dependency information can't be found. |
| + --ignore-weak-undefined only allow strong undefined symbols to introduce |
| + dependencies. |
| --warnings=<value> define set of active warnings (see manual page). |
| --admindir=<directory> change the administrative directory. |
| -?, --help show this help message. |
| -- |
| 2.25.0.rc1.283.g88dfdc4193-goog |
| |
