cc-wrapper: Utilize patched cctools ld for more robust macOS Sierra hack

Also fix numberous bugs, such as:

 - Not getting confused on more flags taking file arguments.

 - Ensuring children reexport their children, but the original
   binary/library doesn't.

 - Not spawning children when it turns out we just dynamically link
   under the threshold but our total number of inputs exceeeds it.

 - Children were always named `libunnamed-*`, when that name was
   supposed to be the last resort only.

ld-wrapper's own RPATH check hardcodes `.so`, but darwin uses `.dylib`
*and* (in practice due to lousy build systems) `.so`. We don't care
however because we never inject `--rpath` like that in practice on
Darwin. Hopefully someday we won't on linux either.
This commit is contained in:
John Ericson 2017-09-06 15:05:30 -04:00
parent 1001311280
commit 1a72330ab0

View file

@ -2,107 +2,245 @@
set -eu -o pipefail
# For cmd | while read; do ...; done
shopt -s lastpipe
path_backup="$PATH"
if [ -n "@coreutils_bin@" ]; then
PATH="@coreutils_bin@/bin"
fi
declare -r recurThreshold=300
declare -ri recurThreshold=200
declare -i overflowCount=0
declare overflowCount=0
for ((n=0; n < $#; ++n)); do
case "${!n}" in
-l*) let overflowCount+=1 ;;
-reexport-l*) let overflowCount+=1 ;;
*) ;;
declare -ar origArgs=("$@")
# Throw away what we won't need
declare -a parentArgs=()
while (( $# )); do
case "$1" in
-l)
echo "cctools LD does not support '-l foo'" >&2
exit 1
;;
-lazy_library | -reexport_library | -upward_library | -weak_library)
overflowCount+=1
shift 2
;;
-l* | *.so.* | *.dylib | -lazy-l* | -reexport-l* | -upward-l* | -weak-l*)
overflowCount+=1
shift 1
;;
*.a | *.o)
shift 1
;;
-L | -F)
# Evidentally ld doesn't like using the child's RPATH, so it still
# needs these.
parentArgs+=("$1" "$2")
shift 2
;;
-L?* | -F?*)
parentArgs+=("$1")
shift 1
;;
-o)
outputName="$2"
parentArgs+=("$1" "$2")
shift 2
;;
-install_name | -dylib_install_name | -dynamic-linker | -plugin)
parentArgs+=("$1" "$2")
shift 2
;;
-rpath)
# Only an rpath to the child is needed, which we will add
shift 2
;;
*)
if [[ -f "$1" ]]; then
# Propabably a non-standard object file like Haskell's
# `.dyn_o`. Skip it like other inputs
:
else
parentArgs+=("$1")
fi
shift 1
;;
esac
done
declare -a allArgs=()
if (( "$overflowCount" <= "$recurThreshold" )); then
allArgs=("$@")
else
declare -a childrenLookup=() childrenLink=()
while (( $# )); do
case "$1" in
-L/*)
childrenLookup+=("$1")
allArgs+=("$1")
;;
-L)
echo "cctools LD does not support '-L foo' or '-l foo'" >&2
exit 1
;;
-l)
echo "cctools LD does not support '-L foo' or '-l foo'" >&2
exit 1
;;
-lazy_library | -lazy_framework | -lto_library)
# We aren't linking any "azy_library", "to_library", etc.
allArgs+=("$1")
;;
-lazy-l | -weak-l) allArgs+=("$1") ;;
# We can't so easily prevent header issues from these.
-lSystem) allArgs+=("$1") ;;
# Special case as indirection seems like a bad idea for something
# so fundamental. Can be removed for simplicity.
-l?* | -reexport-l?*) childrenLink+=("$1") ;;
*) allArgs+=("$1") ;;
esac
shift
done
declare n=0
while (( $n < "${#childrenLink[@]}" )); do
if [[ "${childrenLink[n]}" = -l* ]]; then
childrenLink[n]="-reexport${childrenLink[n]}"
fi
let ++n
done
unset n
declare -r outputNameLibless=$(basename $( \
if [[ -z "${outputName:+isUndefined}" ]]; then
echo unnamed
elif [[ "${outputName:0:3}" = lib ]]; then
echo "${outputName:3}"
else
echo "${outputName}"
fi))
declare -ra children=("$outputNameLibless-reexport-delegate-0" \
"$outputNameLibless-reexport-delegate-1")
mkdir -p "$out/lib"
PATH="$PATH:@out@/bin"
symbolBloatObject=$outputNameLibless-symbol-hack.o
if [[ ! -e $symbolBloatObject ]]; then
# `-Q` means use GNU Assembler rather than Clang, avoiding an awkward
# dependency cycle.
printf '.private_extern _______child_hack_foo\nchild_hack_foo:\n' \
| @targetPrefix@as -Q -- -o $symbolBloatObject
if [ -n "${NIX_DEBUG:-}" ]; then
echo "ld-wrapper: Only ${overflowCount} inputs counted while ${recurThreshold} is the ceiling, linking normally. " >&2
fi
PATH="$path_backup"
exec @prog@ "${origArgs[@]}"
fi
# first half of libs
@targetPrefix@ld -macosx_version_min $MACOSX_DEPLOYMENT_TARGET -arch x86_64 -dylib \
-o "$out/lib/lib${children[0]}.dylib" \
-install_name "$out/lib/lib${children[0]}.dylib" \
"${childrenLookup[@]}" "$symbolBloatObject" \
"${childrenLink[@]:0:$((${#childrenLink[@]} / 2 ))}"
# second half of libs
@targetPrefix@ld -macosx_version_min $MACOSX_DEPLOYMENT_TARGET -arch x86_64 -dylib \
-o "$out/lib/lib${children[1]}.dylib" \
-install_name "$out/lib/lib${children[1]}.dylib" \
"${childrenLookup[@]}" "$symbolBloatObject" \
"${childrenLink[@]:$((${#childrenLink[@]} / 2 ))}"
allArgs+=("-L$out/lib" "-l${children[0]}" "-l${children[1]}")
if [ -n "${NIX_DEBUG:-}" ]; then
echo "ld-wrapper: ${overflowCount} inputs counted when ${recurThreshold} is the ceiling, inspecting further. " >&2
fi
# Collect the normalized linker input
declare -a norm=()
# Arguments are null-separated
@prog@ --dump-normalized-lib-args "${origArgs[@]}" |
while IFS= read -r -d '' input; do
norm+=("$input")
done
declare -i leafCount=0
declare lastLeaf=''
declare -a childrenInputs=() trailingInputs=()
while (( "${#norm[@]}" )); do
case "${norm[0]}" in
-lazy_library | -upward_library)
# TODO(@Ericson2314): Don't do that, but intersperse children
# between such args.
echo "ld-wrapper: Warning: Potentially changing link order" >&2
trailingInputs+=("${norm[0]}" "${norm[1]}")
norm=("${norm[@]:2}")
;;
-reexport_library | -weak_library)
childrenInputs+=("${norm[0]}" "${norm[1]}")
if [[ "${norm[1]}" != "$lastLeaf" ]]; then
leafCount+=1
lastLeaf="${norm[1]}"
fi
norm=("${norm[@]:2}")
;;
*.so | *.dylib)
childrenInputs+=(-reexport_library "${norm[0]}")
if [[ "${norm[0]}" != "$lastLeaf" ]]; then
leafCount+=1
lastLeaf="${norm[0]}"
fi
norm=("${norm[@]:1}")
;;
*.o | *.a)
# Don't delegate object files or static libs
parentArgs+=("${norm[0]}")
norm=("${norm[@]:1}")
;;
*)
if [[ -f "${norm[0]}" ]]; then
# Propabably a non-standard object file. We'll let it by.
parentArgs+=("${norm[0]}")
norm=("${norm[@]:1}")
else
echo "ld-wrapper: Internal Error: Invalid normalized argument" >&2
exit -1
fi
;;
esac
done
if (( "$leafCount" <= "$recurThreshold" )); then
if [ -n "${NIX_DEBUG:-}" ]; then
echo "ld-wrapper: Only ${leafCount} *dynamic* inputs counted while ${recurThreshold} is the ceiling, linking normally. " >&2
fi
PATH="$path_backup"
exec @prog@ "${origArgs[@]}"
fi
if [ -n "${NIX_DEBUG:-}" ]; then
echo "ld-wrapper: ${leafCount} *dynamic* inputs counted when ${recurThreshold} is the ceiling, delegating to children. " >&2
fi
declare -r outputNameLibless=$( \
if [[ -z "${outputName:+isUndefined}" ]]; then
echo unnamed
return 0;
fi
baseName=$(basename ${outputName})
if [[ "$baseName" = lib* ]]; then
baseName="${baseName:3}"
fi
echo "$baseName")
declare -ra children=(
"$outputNameLibless-reexport-delegate-0"
"$outputNameLibless-reexport-delegate-1"
)
mkdir -p "$out/lib"
symbolBloatObject=$outputNameLibless-symbol-hack.o
if [[ ! -f $symbolBloatObject ]]; then
# `-Q` means use GNU Assembler rather than Clang, avoiding an awkward
# dependency cycle.
printf '.private_extern _______child_hack_foo\nchild_hack_foo:\n' |
PATH="$PATH:@out@/bin" @targetPrefix@as -Q -- -o $symbolBloatObject
fi
# Split inputs between children
declare -a child0Inputs=() child1Inputs=("${childrenInputs[@]}")
let "countFirstChild = $leafCount / 2" || true
lastLeaf=''
while (( "$countFirstChild" )); do
case "${child1Inputs[0]}" in
-reexport_library | -weak_library)
child0Inputs+=("${child1Inputs[0]}" "${child1Inputs[1]}")
if [[ "${child1Inputs[1]}" != "$lastLeaf" ]]; then
let countFirstChild-=1 || true
lastLeaf="${child1Inputs[1]}"
fi
child1Inputs=("${child1Inputs[@]:2}")
;;
*.so | *.dylib)
child0Inputs+=(-reexport_library "${child1Inputs[0]}")
if [[ "${child1Inputs[0]}" != "$lastLeaf" ]]; then
let countFirstChild-=1 || true
lastLeaf="${child1Inputs[1]}"
fi
child1Inputs=("${child1Inputs[@]:2}")
;;
*)
echo "ld-wrapper: Internal Error: Invalid delegated input" >&2
exit -1
;;
esac
done
# First half of libs
@out@/bin/@targetPrefix@ld \
-macosx_version_min $MACOSX_DEPLOYMENT_TARGET -arch x86_64 -dylib \
-o "$out/lib/lib${children[0]}.dylib" \
-install_name "$out/lib/lib${children[0]}.dylib" \
"$symbolBloatObject" "${child0Inputs[@]}" "${trailingInputs[@]}"
# Second half of libs
@out@/bin/@targetPrefix@ld \
-macosx_version_min $MACOSX_DEPLOYMENT_TARGET -arch x86_64 -dylib \
-o "$out/lib/lib${children[1]}.dylib" \
-install_name "$out/lib/lib${children[1]}.dylib" \
"$symbolBloatObject" "${child1Inputs[@]}" "${trailingInputs[@]}"
parentArgs+=("-L$out/lib" -rpath "$out/lib")
if [[ $outputName != *reexport-delegate* ]]; then
parentArgs+=("-l${children[0]}" "-l${children[1]}")
else
parentArgs+=("-reexport-l${children[0]}" "-reexport-l${children[1]}")
fi
parentArgs+=("${trailingInputs[@]}")
if [ -n "${NIX_DEBUG:-}" ]; then
echo "flags using delegated children to @prog@:" >&2
printf " %q\n" "${parentArgs[@]}" >&2
fi
PATH="$path_backup"
exec @prog@ "${allArgs[@]}"
exec @prog@ "${parentArgs[@]}"