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![Marek Behún](/assets/img/avatar_default.png)
Add plumbing for building U-Boot with Link Time Optimizations. When building with LTO, $(PLATFORM_LIBS) has to be in --whole-archive / --no-whole-archive group, otherwise some functions declared in assembly may not be resolved and linking may fail. Note: clang may throw away linker list symbols it thinks are unused when compiling with LTO. To force these symbols to be included, we refer to them via the __ADDRESSABLE macro in a C file generated from compiled built-in.o files before linking. Signed-off-by: Marek Behún <marek.behun@nic.cz> Reviewed-by: Simon Glass <sjg@chromium.org>
13 lines
412 B
Bash
Executable File
13 lines
412 B
Bash
Executable File
#!/bin/bash
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# SPDX-License-Identifier: GPL-2.0+
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# Copyright (C) 2020 Marek Behún <marek.behun@nic.cz>
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# Generate __ADDRESSABLE(symbol) for every linker list entry symbol, so that LTO
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# does not optimize these symbols away
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set -e
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echo '#include <common.h>'
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$NM "$@" 2>/dev/null | grep -oe '_u_boot_list_2_[a-zA-Z0-9_]*_2_[a-zA-Z0-9_]*' | \
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sort -u | sed -e 's/^\(.*\)/extern char \1[];\n__ADDRESSABLE(\1);/'
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