From 58b81ac621aea1428aa9e7ca20ad45fc18dba9f7 Mon Sep 17 00:00:00 2001
From: "Avi Halachmi (:avih)" <avihpit@yahoo.com>
Date: Mon, 30 Jul 2018 22:39:15 +0300
Subject: [PATCH] configure: speed up flatten_extralibs_wrapper()
x50 - x200 faster.
Currently configure spends 50-70% of its runtime inside a single
function: flatten_extralibs[_wrapper] - which does string processing.
During its run, nearly 20K command substitutions (subshells) are used,
including its callees unique() and resolve(), which is the reason
for its lengthy run.
This commit avoids all subshells during its execution, speeding it up
by about two orders of magnitude, and reducing the overall configure
runtime by 50-70% .
resolve() is rewritten to avoid subshells, and in unique() and
flatten_extralibs() we "inline" the filter[_out] functionality.
Note that logically, "unique" functionality has more than one possible
output (depending on which of the recurring items is kept). As it
turns out, other parts expect the last recurring item to be kept
(which was the original behavior of uniqie()). This patch preservs
its output order.
Tested-by: Michael Niedermayer <michael@niedermayer.cc>
Tested-by: Helmut K. C. Tessarek <tessarek@evermeet.cx>
Tested-by: Dave Yeo <daveryeo@telus.net>
Tested-by: Reino Wijnsma <rwijnsma@xs4all.nl>
Signed-off-by: James Almer <jamrial@gmail.com>
---
configure | 46 +++++++++++++++++++++++++++++++++-------------
1 file changed, 33 insertions(+), 13 deletions(-)
diff --git a/configure b/configure
index b9c9d0b3075..95a38cf20e9 100755
--- a/configure
+++ b/configure
@@ -844,22 +844,37 @@ prepend(){
eval "$var=\"$* \$$var\""
}
+reverse () {
+ eval '
+ reverse_out=
+ for v in $'$1'; do
+ reverse_out="$v $reverse_out"
+ done
+ '$1'=$reverse_out
+ '
+}
+
+# keeps the last occurence of each non-unique item
unique(){
- var=$1
- uniq_list=""
- for tok in $(eval echo \$$var); do
- uniq_list="$(filter_out $tok $uniq_list) $tok"
+ unique_out=
+ eval unique_in=\$$1
+ reverse unique_in
+ for v in $unique_in; do
+ # " $unique_out" +space such that every item is surrounded with spaces
+ case " $unique_out" in *" $v "*) continue; esac # already in list
+ unique_out="$unique_out$v "
done
- eval "$var=\"${uniq_list}\""
+ reverse unique_out
+ eval $1=\$unique_out
}
resolve(){
- var=$1
- tmpvar=
- for entry in $(eval echo \$$var); do
- tmpvar="$tmpvar $(eval echo \$${entry})"
+ resolve_out=
+ eval resolve_in=\$$1
+ for v in $resolve_in; do
+ eval 'resolve_out="$resolve_out$'$v' "'
done
- eval "$var=\"${tmpvar}\""
+ eval $1=\$resolve_out
}
add_cppflags(){
@@ -6734,14 +6749,19 @@ if test $target_os = "haiku"; then
fi
flatten_extralibs(){
- unset nested_entries
+ nested_entries=
list_name=$1
eval list=\$${1}
for entry in $list; do
entry_copy=$entry
resolve entry_copy
- append nested_entries $(filter '*_extralibs' $entry_copy)
- flat_entries=$(filter_out '*_extralibs' $entry_copy)
+ flat_entries=
+ for e in $entry_copy; do
+ case $e in
+ *_extralibs) nested_entries="$nested_entries$e ";;
+ *) flat_entries="$flat_entries$e ";;
+ esac
+ done
eval $entry="\$flat_entries"
done
append $list_name "$nested_entries"
--
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