2fcee55e5f
For instance, a binary like libfoo.so will cause a symlink lib/debug/libfoo.so.debug -> .build-id/<build-ID>.debug to be created. This is primarily useful for use with eu-addr2line, if you know the name of a binary and the relative address, but not the build ID.
47 lines
1.7 KiB
Bash
47 lines
1.7 KiB
Bash
export NIX_LDFLAGS+=" --build-id"
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export NIX_CFLAGS_COMPILE+=" -ggdb"
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dontStrip=1
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fixupOutputHooks+=(_separateDebugInfo)
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_separateDebugInfo() {
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local dst="${debug:-$out}"
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if [ "$prefix" = "$dst" ]; then return; fi
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dst="$dst/lib/debug/.build-id"
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# Find executables and dynamic libraries.
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local -a files=($(find "$prefix" -type f -a \( -perm /0100 -o -name "*.so" -o -name "*.so.*" \)))
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local i magic
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for i in "${files[@]}"; do
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# Skip non-ELF files.
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exec 10< "$i"
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read -n 4 -u 10 magic
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exec 10<&-
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# Extract the Build ID. FIXME: there's probably a cleaner way.
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local id="$(readelf -n "$i" | sed 's/.*Build ID: \([0-9a-f]*\).*/\1/; t; d')"
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if [ "${#id}" != 40 ]; then
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echo "could not find build ID of $i, skipping" >&2
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continue
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fi
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# Extract the debug info.
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header "separating debug info from $i (build ID $id)"
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mkdir -p "$dst/${id:0:2}"
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objcopy --only-keep-debug "$i" "$dst/${id:0:2}/${id:2}.debug" --compress-debug-sections
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strip --strip-debug "$i"
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# Also a create a symlink <original-name>.debug.
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ln -sfn ".build-id/${id:0:2}/${id:2}.debug" "$dst/../$(basename "$i")"
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done
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}
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# - We might prefer to compress the debug info during link-time already,
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# but our ld doesn't support --compress-debug-sections=zlib (yet).
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# - Debug info may cause problems due to excessive memory usage during linking.
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# Using -Wa,--compress-debug-sections should help with that;
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# further interesting information: https://gcc.gnu.org/wiki/DebugFission
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# - Another related tool: https://fedoraproject.org/wiki/Features/DwarfCompressor
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