Commit 020d7f14 authored by Thomas Weißschuh's avatar Thomas Weißschuh Committed by Masahiro Yamada
Browse files

Revert "kbuild: make all file references relative to source root" 



This reverts commit cacd22ce.

-ffile-prefix-map breaks the ability of debuggers to find the source
file corresponding to object files. As there is no simple or uniform
way to specify the source directory explicitly, this breaks developers
workflows.

Revert the unconditional usage of -ffile-prefix-map.

Reported-by: default avatarMatthieu Baerts <matttbe@kernel.org>
Closes: https://lore.kernel.org/lkml/edc50aa7-0740-4942-8c15-96f12f2acc7e@kernel.org/


Reported-by: default avatarVille Syrjälä <ville.syrjala@linux.intel.com>
Closes: https://lore.kernel.org/lkml/aBEttQH4kimHFScx@intel.com/


Fixes: cacd22ce ("kbuild: make all file references relative to source root")
Signed-off-by: default avatarThomas Weißschuh <linux@weissschuh.net>
Signed-off-by: default avatarMasahiro Yamada <masahiroy@kernel.org>
parent f0e4b333

Documentation/kbuild/reproducible-builds.rst

+17 −0
Original line number Diff line number Diff line
@@ -46,6 +46,21 @@ The kernel embeds the building user and host names in 
`KBUILD_BUILD_USER and KBUILD_BUILD_HOST`_ variables.  If you are

building from a git commit, you could use its committer address.



Absolute filenames

------------------



When the kernel is built out-of-tree, debug information may include

absolute filenames for the source files.  This must be overridden by

including the ``-fdebug-prefix-map`` option in the `KCFLAGS`_ variable.



Depending on the compiler used, the ``__FILE__`` macro may also expand

to an absolute filename in an out-of-tree build.  Kbuild automatically

uses the ``-fmacro-prefix-map`` option to prevent this, if it is

supported.



The Reproducible Builds web site has more information about these

`prefix-map options`_.



Generated files in source packages

----------------------------------
@@ -116,5 +131,7 @@ See ``scripts/setlocalversion`` for details. 


.. _KBUILD_BUILD_TIMESTAMP: kbuild.html#kbuild-build-timestamp

.. _KBUILD_BUILD_USER and KBUILD_BUILD_HOST: kbuild.html#kbuild-build-user-kbuild-build-host

.. _KCFLAGS: kbuild.html#kcflags

.. _prefix-map options: https://reproducible-builds.org/docs/build-path/

.. _Reproducible Builds project: https://reproducible-builds.org/

.. _SOURCE_DATE_EPOCH: https://reproducible-builds.org/docs/source-date-epoch/

Makefile

+1 −1
Original line number Diff line number Diff line
@@ -1068,7 +1068,7 @@ KBUILD_CFLAGS += -fno-builtin-wcslen 


# change __FILE__ to the relative path to the source directory

ifdef building_out_of_srctree

KBUILD_CPPFLAGS += $(call cc-option,-ffile-prefix-map=$(srcroot)/=)

KBUILD_CPPFLAGS += $(call cc-option,-fmacro-prefix-map=$(srcroot)/=)

KBUILD_RUSTFLAGS += --remap-path-prefix=$(srcroot)/=

endif