dh_dwz man page

dh_dwz — optimize DWARF debug information in ELF binaries via dwz

Synopsis

dh_dwz [debhelper options] [-Xitem] [-- params]

Description

dh_dwz is a debhelper program that will optimize the (uncompressed) size of the DWARF debug information in ELF binaries.  It does so by running dwz(1) on all the ELF binaries in the package.

Options

--dwz-multifile, --no-dwz-multifile

Whether dwz(1) should generate a multifile from the ELF binaries in the same package.  When enabled, if a package ships at least 2 ELF binaries, dh_dwz will instruct dwz(1) to generate a multifile for the package.

By default, dh_dwz will attempt to create a multifile but will continue without if dwz(1) does create one (but succeeds anyway). This commonly happens when the debug files do not contain debug symbols (e.g. a missing -g to the compiler) or when the debug symbols are compressed (see Debian bug #931891).  If --dwz-multifile is passed, then dh_dwz will abort with an error if dwz(1) does not create a multifile.

Note this options may not work if a package contains more ELF binaries than can fit on a single command line.  If this becomes a problem, please pass --no-dwz-multifile to work around the issue.

The generated multifile will be compressed with objcopy --compress-debug-sections.

Note for udeb packages: dh_dwz will never generate multifiles for udeb packages.  It will still use dwz to reduce the file size of debug files if it finds any.

-Xitem, --exclude=item

Exclude files that contain item anywhere in their filename from being stripped. You may use this option multiple times to build up a list of things to exclude.

-- params

Pass params to dwz(1) when it processes ELF binaries.  This is mostly useful for setting memory related parameters (e.g. -l and -L).

Notes

If the DEB_BUILD_OPTIONS environment variable contains nostrip, nothing will be stripped, in accordance with Debian policy (section 10.1 “Binaries”).

While this tool technically does not remove debug information from binaries, it is still skipped when the DEB_BUILD_OPTIONS environment variable contains nostrip.  This is because nostrip is often used to optimize build times (e.g. for “build and test”-cycles) rather than optimizing for size.

See Also

debhelper(7)

This program is a part of debhelper.

Author

Niels Thykier <niels@thykier.net>

Referenced By

debhelper(7).

2019-10-08 12.6.1 Debhelper