On Thu, 20 May 2021 at 05:25, Marek Behún marek.behun@nic.cz wrote:
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
Kbuild | 2 + Kconfig | 24 ++++++++++ Makefile | 67 ++++++++++++++++++++++++++- scripts/Makefile.lib | 3 ++ scripts/Makefile.spl | 44 +++++++++++++++++- scripts/gen_ll_addressable_symbols.sh | 12 +++++
That is very long. How about gen_linkerlist_syms.sh ?
6 files changed, 149 insertions(+), 3 deletions(-) create mode 100755 scripts/gen_ll_addressable_symbols.sh
Reviewed-by: Simon Glass sjg@chromium.org