72 lines
1.9 KiB
Bash
Executable File
72 lines
1.9 KiB
Bash
Executable File
#!/usr/bin/env bash
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# SPDX-License-Identifier: GPL-2.0-only
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#
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# Copyright (C) 2022 Masahiro Yamada <masahiroy@kernel.org>
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#
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# Exit with error if a local exported symbol is found.
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# EXPORT_SYMBOL should be used for global symbols.
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set -e
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# catch errors from ${NM}
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set -o pipefail
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# Run the last element of a pipeline in the current shell.
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# Without this, the while-loop would be executed in a subshell, and
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# the changes made to 'symbol_types' and 'export_symbols' would be lost.
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shopt -s lastpipe
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declare -A symbol_types
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declare -a export_symbols
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exit_code=0
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# If there is no symbol in the object, ${NM} (both GNU nm and llvm-nm) shows
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# 'no symbols' diagnostic (but exits with 0). It is harmless and hidden by
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# '2>/dev/null'. However, it suppresses real error messages as well. Add a
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# hand-crafted error message here.
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#
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# TODO:
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# Use --quiet instead of 2>/dev/null when we upgrade the minimum version of
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# binutils to 2.37, llvm to 13.0.0.
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# Then, the following line will be really simple:
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# ${NM} --quiet ${1} |
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{ ${NM} ${1} 2>/dev/null || { echo "${0}: ${NM} failed" >&2; false; } } |
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while read value type name
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do
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# Skip the line if the number of fields is less than 3.
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#
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# case 1)
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# For undefined symbols, the first field (value) is empty.
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# The outout looks like this:
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# " U _printk"
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# It is unneeded to record undefined symbols.
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#
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# case 2)
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# For Clang LTO, llvm-nm outputs a line with type 't' but empty name:
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# "---------------- t"
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if [[ -z ${name} ]]; then
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continue
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fi
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# save (name, type) in the associative array
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symbol_types[${name}]=${type}
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# append the exported symbol to the array
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if [[ ${name} == __ksymtab_* ]]; then
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export_symbols+=(${name#__ksymtab_})
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fi
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done
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for name in "${export_symbols[@]}"
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do
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# nm(3) says "If lowercase, the symbol is usually local"
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if [[ ${symbol_types[$name]} =~ [a-z] ]]; then
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echo "$@: error: local symbol '${name}' was exported" >&2
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exit_code=1
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fi
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done
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exit ${exit_code}
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