nixpkgs/pkgs/build-support/setup-hooks/separate-debug-info.sh
Eelco Dolstra d5bb6a1f9c glibc: Enable separate debug symbols
The importance of glibc makes it worthwhile to provide debug
symbols. However, this revealed an issue with separateDebugInfo: it
was indiscriminately adding --build-id to all ld invocations, while in
fact it should only do that for final links. Glibc also uses non-final
("relocatable") links, leading to subsequent failure to apply a build
ID ("Cannot create .note.gnu.build-id section, --build-id
ignored"). So now ld-wrapper.sh only passes --build-id for final
links.
2016-02-28 02:57:37 +01:00

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export NIX_SET_BUILD_ID=1
export NIX_LDFLAGS+=" --compress-debug-sections=zlib"
export NIX_CFLAGS_COMPILE+=" -ggdb -Wa,--compress-debug-sections"
dontStrip=1
fixupOutputHooks+=(_separateDebugInfo)
_separateDebugInfo() {
local dst="${debug:-$out}"
if [ "$prefix" = "$dst" ]; then return; fi
dst="$dst/lib/debug/.build-id"
# Find executables and dynamic libraries.
local i magic
while IFS= read -r -d $'\0' i; do
if ! isELF "$i"; then continue; fi
# Extract the Build ID. FIXME: there's probably a cleaner way.
local id="$(readelf -n "$i" | sed 's/.*Build ID: \([0-9a-f]*\).*/\1/; t; d')"
if [ "${#id}" != 40 ]; then
echo "could not find build ID of $i, skipping" >&2
continue
fi
# Extract the debug info.
header "separating debug info from $i (build ID $id)"
mkdir -p "$dst/${id:0:2}"
objcopy --only-keep-debug "$i" "$dst/${id:0:2}/${id:2}.debug"
strip --strip-debug "$i"
# Also a create a symlink <original-name>.debug.
ln -sfn ".build-id/${id:0:2}/${id:2}.debug" "$dst/../$(basename "$i")"
done < <(find "$prefix" -type f -print0)
}