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ld-wrapper: Optimize expanding rpath

The time to expand rpath was proportional to the number of -L flags times the
number of -l flags.  Now it is proportional to their sum (assuming constant
number of files in each directory in an -L flag).

Issue reported by @nh2 at https://github.com/NixOS/nixpkgs/issues/27609#issuecomment-317916623
This commit is contained in:
Orivej Desh 2017-07-26 09:30:00 +00:00
parent 34c0ba498c
commit 4964b104b9

View file

@ -1,4 +1,5 @@
#! @shell@ -e
shopt -s nullglob
path_backup="$PATH"
if [ -n "@coreutils_bin@" ]; then
PATH="@coreutils_bin@/bin"
@ -20,18 +21,19 @@ expandResponseParams "$@"
if [ "$NIX_ENFORCE_PURITY" = 1 -a -n "$NIX_STORE" \
-a \( -z "$NIX_IGNORE_LD_THROUGH_GCC" -o -z "$NIX_LDFLAGS_SET" \) ]; then
rest=()
n=0
while [ $n -lt ${#params[*]} ]; do
nParams=${#params[@]}
declare -i n=0
while [ $n -lt $nParams ]; do
p=${params[n]}
p2=${params[$((n+1))]}
if [ "${p:0:3}" = -L/ ] && badPath "${p:2}"; then
skip $p
skip "${p:2}"
elif [ "$p" = -L ] && badPath "$p2"; then
n=$((n + 1)); skip $p2
n+=1; skip "$p2"
elif [ "$p" = -rpath ] && badPath "$p2"; then
n=$((n + 1)); skip $p2
n+=1; skip "$p2"
elif [ "$p" = -dynamic-linker ] && badPath "$p2"; then
n=$((n + 1)); skip $p2
n+=1; skip "$p2"
elif [ "${p:0:1}" = / ] && badPath "$p"; then
# We cannot skip this; barf.
echo "impure path \`$p' used in link" >&2
@ -40,9 +42,9 @@ if [ "$NIX_ENFORCE_PURITY" = 1 -a -n "$NIX_STORE" \
# Our ld is not built with sysroot support (Can we fix that?)
:
else
rest=("${rest[@]}" "$p")
rest+=("$p")
fi
n=$((n + 1))
n+=1
done
params=("${rest[@]}")
fi
@ -50,7 +52,7 @@ fi
LD=@prog@
source @out@/nix-support/add-hardening.sh
extra=(${hardeningLDFlags[@]})
extra=("${hardeningLDFlags[@]}")
extraBefore=()
if [ -z "$NIX_LDFLAGS_SET" ]; then
@ -60,122 +62,97 @@ fi
extra+=($NIX_LDFLAGS_AFTER $NIX_LDFLAGS_HARDEN)
declare -A rpaths
declare -a libDirs
declare -A libs
relocatable=
# Find all -L... switches for rpath, and relocatable flags for build id.
if [ "$NIX_DONT_SET_RPATH" != 1 ] || [ "$NIX_SET_BUILD_ID" = 1 ]; then
prev=
for p in "${params[@]}" "${extra[@]}"; do
case "$prev" in
-L)
libDirs+=("$p")
;;
-l)
libs["lib${p}.so"]=1
;;
-dynamic-linker)
# Ignore the dynamic linker argument, or it
# will match *.so and be added to rpath.
;;
*)
case "$p" in
-L/*)
libDirs+=("${p:2}")
;;
-l?*)
libs["lib${p:2}.so"]=1
;;
"$NIX_STORE"/*.so | "$NIX_STORE"/*.so.*)
# This is a direct reference to a shared library, so add
# its directory to the rpath.
dir="${p%/*}"
if [ ! "${rpaths[$dir]}" ]; then
rpaths["$dir"]=1
extra+=(-rpath "$dir")
fi
;;
-r | --relocatable | -i)
relocatable=1
esac
;;
esac
prev="$p"
done
fi
# Add all used dynamic libraries to the rpath.
if [ "$NIX_DONT_SET_RPATH" != 1 ]; then
declare -A libDirsSeen
declare -a libDirs
addToLibPath() {
local path="$1"
if [ "${path:0:1}" != / ]; then return 0; fi
case "$path" in
*..*|*./*|*/.*|*//*)
local path2
if path2=$(readlink -f "$path"); then
path="$path2"
fi
;;
esac
if [[ -z ${libDirsSeen[$path]} ]]; then
libDirs+=("$path")
libDirsSeen[$path]=1
fi
}
declare -A rpathsSeen
declare -a rpaths
addToRPath() {
# If the path is not in the store, don't add it to the rpath.
# This typically happens for libraries in /tmp that are later
# copied to $out/lib. If not, we're screwed.
if [ "${1:0:${#NIX_STORE}}" != "$NIX_STORE" ]; then return 0; fi
if [[ -z ${rpathsSeen[$1]} ]]; then
rpaths+=("$1")
rpathsSeen[$1]=1
fi
}
declare -a libs
# First, find all -L... switches.
allParams=("${params[@]}" ${extra[@]})
n=0
while [ $n -lt ${#allParams[*]} ]; do
p=${allParams[n]}
p2=${allParams[$((n+1))]}
if [ "${p:0:3}" = -L/ ]; then
addToLibPath ${p:2}
elif [ "$p" = -L ]; then
addToLibPath ${p2}
n=$((n + 1))
elif [ "$p" = -l ]; then
libs+=(${p2})
n=$((n + 1))
elif [ "${p:0:2}" = -l ]; then
libs+=(${p:2})
elif [ "$p" = -dynamic-linker ]; then
# Ignore the dynamic linker argument, or it
# will get into the next 'elif'. We don't want
# the dynamic linker path rpath to go always first.
n=$((n + 1))
elif [[ "$p" =~ ^[^-].*\.so($|\.) ]]; then
# This is a direct reference to a shared library, so add
# its directory to the rpath.
path="$(dirname "$p")";
addToRPath "${path}"
fi
n=$((n + 1))
done
# Second, for each directory in the library search path (-L...),
# For each directory in the library search path (-L...),
# see if it contains a dynamic library used by a -l... flag. If
# so, add the directory to the rpath.
# It's important to add the rpath in the order of -L..., so
# the link time chosen objects will be those of runtime linking.
for i in ${libDirs[@]}; do
for j in ${libs[@]}; do
if [ -f "$i/lib$j.so" ]; then
addToRPath $i
break
for dir in "${libDirs[@]}"; do
if [[ "$dir" =~ [/.][/.] ]] && dir2=$(readlink -f "$dir"); then
dir="$dir2"
fi
if [ "${rpaths[$dir]}" ] || [[ "$dir" != "$NIX_STORE"/* ]]; then
# If the path is not in the store, don't add it to the rpath.
# This typically happens for libraries in /tmp that are later
# copied to $out/lib. If not, we're screwed.
continue
fi
for path in "$dir"/lib*.so; do
file="${path##*/}"
if [ "${libs[$file]}" ]; then
libs["$file"]=
if [ ! "${rpaths[$dir]}" ]; then
rpaths["$dir"]=1
extra+=(-rpath "$dir")
fi
fi
done
done
# Finally, add `-rpath' switches.
for i in ${rpaths[@]}; do
extra+=(-rpath "$i")
done
fi
# Only add --build-id if this is a final link. FIXME: should build gcc
# with --enable-linker-build-id instead?
if [ "$NIX_SET_BUILD_ID" = 1 ]; then
for p in "${params[@]}"; do
if [ "$p" = "-r" -o "$p" = "--relocatable" -o "$p" = "-i" ]; then
relocatable=1
break
fi
done
if [ -z "$relocatable" ]; then
extra+=(--build-id)
fi
if [ "$NIX_SET_BUILD_ID" = 1 ] && [ ! "$relocatable" ]; then
extra+=(--build-id)
fi
# Optionally print debug info.
if [ -n "$NIX_DEBUG" ]; then
echo "original flags to @prog@:" >&2
for i in "${params[@]}"; do
echo " $i" >&2
done
echo "extra flags to @prog@:" >&2
for i in ${extra[@]}; do
echo " $i" >&2
done
echo "original flags to @prog@:" >&2
printf " %q\n" "${params[@]}" >&2
echo "extra flags to @prog@:" >&2
printf " %q\n" "${extraBefore[@]}" "${extra[@]}" >&2
fi
if [ -n "$NIX_LD_WRAPPER_EXEC_HOOK" ]; then
@ -183,4 +160,4 @@ if [ -n "$NIX_LD_WRAPPER_EXEC_HOOK" ]; then
fi
PATH="$path_backup"
exec @prog@ ${extraBefore[@]} "${params[@]}" ${extra[@]}
exec @prog@ "${extraBefore[@]}" "${params[@]}" "${extra[@]}"