Some toolchains are compiled so that they pass a --build-id=something
parameter to the linker implicitly.

This causes U-Boot LTO linking to fail with something like:
  ld: section .note.gnu.build-id LMA ... overlaps section .text LMA ...
because U-Boot's link scripts do not currently handle .note.gnu.build-id
section.

Fix this by explicitly disabling build-id.

Signed-off-by: Marek Behún <marek.behun@nic.cz>
Reviewed-by: Simon Glass <sjg@chromium.org>

Add plumbing for building U-Boot with Link Time Optimizations.

When building with LTO, $(PLATFORM_LIBS) has to be in --whole-archive /
--no-whole-archive group, otherwise some functions declared in assembly
may not be resolved and linking may fail.

Note: clang may throw away linker list symbols it thinks are unused when
compiling with LTO. To force these symbols to be included, we refer to
them via the __ADDRESSABLE macro in a C file generated from compiled
built-in.o files before linking.

Signed-off-by: Marek Behún <marek.behun@nic.cz>
Reviewed-by: Simon Glass <sjg@chromium.org>

Currently we use incremental linking (ld -r) to link several object
files from one directory into one built-in.o object file containing the
linked code from that directory (and its subdirectories).

Linux has, some time ago, moved to thin archives instead.

Thin archives are archives (.a) that do not really contain the object
files, only references to them.

Using thin archives instead of incremental linking
- saves disk space
- apparently works better with dead code elimination
- makes things easier for LTO

The third point is the important one for us. With incremental linking
there are several options how to do LTO, and that would unnecessarily
complicate things.

We have to use the --whole-archive/--no-whole-archive linking option
instead of --start-group/--end-group, otherwise linking may fail because
of unresolved symbols, or the resulting binary will be unusable.

We also need to use the P flag for ar, otherwise final linking may fail.

Signed-off-by: Marek Behún <marek.behun@nic.cz>
Reviewed-by: Simon Glass <sjg@chromium.org>

Indent the linking commands so that they look cosmetically better.

Signed-off-by: Marek Behún <marek.behun@nic.cz>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>

This is how Linux does this now, see Linux commit 339f29d91acf.

Signed-off-by: Marek Behún <marek.behun@nic.cz>
Reviewed-by: Simon Glass <sjg@chromium.org>

Clang has -Wself-assign enabled by default under -Wall and so when
building with -Werror we would get an error here.  Inspired by Linux
kernel git commit a21151b9d81a ("tools/build: tweak unused value
workaround") make use of the fact that both Clang and GCC support
casting to `void` as the method to note that something is intentionally
unused.

Signed-off-by: Tom Rini <trini@konsulko.com>

Rsync all defconfig files using moveconfig.py

Signed-off-by: Tom Rini <trini@konsulko.com>

Parse each empty-line-delimited message separately. This saves having to
deal with all the different line content styles, we only care about the
header ERROR | WARNING | NOTE...

Also make checkpatch print line information for a uboot specific
warning.

Signed-off-by: Evan Benn <evanbenn@chromium.org>
Reviewed-by: Simon Glass <sjg@chromium.org>

Rsync all defconfig files using moveconfig.py

Signed-off-by: Tom Rini <trini@konsulko.com>

Migrate CONFIG_LMB in Kconfig.

Signed-off-by: Patrick Delaunay <patrick.delaunay@foss.st.com>