Add "make change" target to build the big toybox binary as a bunch of little ones (in the "change" subdirectory), and tweak scripts/make.sh to avoid redundant work when rebuilding.

1 files changed, 120 insertions, 80 deletions

diff --git a/scripts/make.sh b/scripts/make.sh
index dab52061..2274d68b 100755
--- a/scripts/make.sh
+++ b/scripts/make.sh
@@ -15,13 +15,95 @@ source ./configure
   CPUS=$((($(echo /sys/devices/system/cpu/cpu[0-9]* | wc -w)*3)/2))
 
 # Respond to V= by echoing command lines as well as running them
+DOTPROG=
 do_loudly()
 {
-  [ ! -z "$V" ] && echo "$@"
+  [ ! -z "$V" ] && echo "$@" || echo -n "$DOTPROG"
   "$@"
 }
 
+# Is anything under directory $2 newer than file $1
+isnewer()
+{
+ [ ! -z "$(find "$2" -newer "$1" 2>/dev/null || echo yes)" ]
+}
+
+echo "Generate headers from toys/*/*.c..."
+
 mkdir -p generated
+
+if isnewer generated/Config.in toys
+then
+  echo "Extract configuration information from toys/*.c files..."
+  scripts/genconfig.sh
+fi
+
+# Create a list of all the commands toybox can provide. Note that the first
+# entry is out of order on purpose (the toybox multiplexer command must be the
+# first element of the array). The rest must be sorted in alphabetical order
+# for fast binary search.
+
+if isnewer generated/newtoys.h toys
+then
+  echo -n "generated/newtoys.h "
+
+  echo "USE_TOYBOX(NEWTOY(toybox, NULL, TOYFLAG_STAYROOT))" > generated/newtoys.h
+  sed -n -e 's/^USE_[A-Z0-9_]*(/&/p' toys/*/*.c \
+	| sed 's/\(.*TOY(\)\([^,]*\),\(.*\)/\2 \1\2,\3/' | sort -k 1,1 \
+	| sed 's/[^ ]* //'  >> generated/newtoys.h &&
+  sed -n -e 's/.*(NEWTOY(\([^,]*\), *\(\("[^"]*"[^,]*\)*\),.*/#define OPTSTR_\1\t\2/p' \
+    generated/newtoys.h > generated/oldtoys.h || exit 1
+fi
+
+[ ! -z "$V" ] && echo "Which C files to build..."
+
+# Extract a list of toys/*/*.c files to compile from the data in $KCONFIG_CONFIG
+TOYFILES="$(egrep -l "TOY[(]($(sed -n 's/^CONFIG_\([^=]*\)=.*/\1/p' "$KCONFIG_CONFIG" | xargs | tr ' [A-Z]' '|[a-z]'))[ ,]" toys/*/*.c)"
+BUILD="$(echo ${CROSS_COMPILE}${CC} $CFLAGS -I . $OPTIMIZE)"
+FILES="$(echo lib/*.c main.c $TOYFILES)"
+
+genbuildsh()
+{
+  # Write a canned build line for use on crippled build machines.
+
+  echo "#!/bin/sh"
+  echo
+  echo "BUILD=\"$BUILD\""
+  echo
+  echo "FILES=\"$FILES\""
+  echo
+  echo "LINK=\"$LINK\""
+  echo
+  echo
+  echo '$BUILD $FILES $LINK'
+}
+
+if ! cmp -s <(genbuildsh | head -n 3) \
+          <(head -n 3 generated/build.sh 2>/dev/null)
+then
+  echo -n "Library probe"
+
+  # We trust --as-needed to remove each library if we don't use any symbols
+  # out of it, this loop is because the compiler has no way to ignore a library
+  # that doesn't exist, so we have to detect and skip nonexistent libraries
+  # for it.
+
+  > generated/optlibs.dat
+  for i in util crypt m resolv
+  do
+    echo "int main(int argc, char *argv[]) {return 0;}" | \
+    ${CROSS_COMPILE}${CC} $CFLAGS -xc - -o /dev/null -Wl,--as-needed -l$i > /dev/null 2>/dev/null &&
+    echo -l$i >> generated/optlibs.dat
+    echo -n .
+  done
+  echo
+fi
+
+# LINK needs optlibs.dat, above
+
+LINK="$(echo $LDOPTIMIZE -o toybox_unstripped -Wl,--as-needed $(cat generated/optlibs.dat))"
+genbuildsh > generated/build.sh && chmod +x generated/build.sh || exit 1
+
 echo "Make generated/config.h from $KCONFIG_CONFIG."
 
 # This long and roundabout sed invocation is to make old versions of sed happy.
@@ -48,27 +130,10 @@ sed -n \
   -e 's/.*/#define USE_&(...) __VA_ARGS__/p' \
   $KCONFIG_CONFIG > generated/config.h || exit 1
 
-
-echo "Extract configuration information from toys/*.c files..."
-scripts/genconfig.sh
-
-echo "Generate headers from toys/*/*.c..."
-
-# Create a list of all the commands toybox can provide. Note that the first
-# entry is out of order on purpose (the toybox multiplexer command must be the
-# first element of the array). The rest must be sorted in alphabetical order
-# for fast binary search.
-
-echo -n "generated/newtoys.h "
-
-echo "USE_TOYBOX(NEWTOY(toybox, NULL, TOYFLAG_STAYROOT))" > generated/newtoys.h
-sed -n -e 's/^USE_[A-Z0-9_]*(/&/p' toys/*/*.c \
-	| sed 's/\(.*TOY(\)\([^,]*\),\(.*\)/\2 \1\2,\3/' | sort -k 1,1 \
-	| sed 's/[^ ]* //'  >> generated/newtoys.h
-sed -n -e 's/.*(NEWTOY(\([^,]*\), *\(\("[^"]*"[^,]*\)*\),.*/#define OPTSTR_\1\t\2/p' \
-  generated/newtoys.h > generated/oldtoys.h
-
-do_loudly $HOSTCC scripts/mkflags.c -o generated/mkflags || exit 1
+if [ generated/mkflags -ot scripts/mkflags.c ]
+then
+  do_loudly $HOSTCC scripts/mkflags.c -o generated/mkflags || exit 1
+fi
 
 echo -n "generated/flags.h "
 
@@ -126,80 +191,55 @@ function getglobals()
   done
 }
 
-echo -n "generated/globals.h "
-
-GLOBSTRUCT="$(getglobals)"
-(
-  echo "$GLOBSTRUCT"
-  echo
-  echo "extern union global_union {"
-  echo "$GLOBSTRUCT" | sed -n 's/struct \(.*\)_data {/	struct \1_data \1;/p'
-  echo "} this;"
-) > generated/globals.h
+if isnewer generated/globals.h toys
+then
+  echo -n "generated/globals.h "
+  GLOBSTRUCT="$(getglobals)"
+  (
+    echo "$GLOBSTRUCT"
+    echo
+    echo "extern union global_union {"
+    echo "$GLOBSTRUCT" | \
+      sed -n 's/struct \(.*\)_data {/	struct \1_data \1;/p'
+    echo "} this;"
+  ) > generated/globals.h
+fi
 
 echo "generated/help.h"
-do_loudly $HOSTCC scripts/config2help.c -I . lib/xwrap.c lib/llist.c lib/lib.c \
-  -o generated/config2help && \
+if [ generated/config2help -ot scripts/config2help.c ]
+then
+  do_loudly $HOSTCC scripts/config2help.c -I . lib/xwrap.c lib/llist.c \
+    lib/lib.c -o generated/config2help || exit 1
+fi
 generated/config2help Config.in $KCONFIG_CONFIG > generated/help.h || exit 1
 
-echo -n "Library probe"
-
-# We trust --as-needed to remove each library if we don't use any symbols
-# out of it, this loop is because the compiler has no way to ignore a library
-# that doesn't exist, so we have to detect and skip nonexistent libraries
-# for it.
-
-> generated/optlibs.dat
-for i in util crypt m resolv
-do
-  echo "int main(int argc, char *argv[]) {return 0;}" | \
-  ${CROSS_COMPILE}${CC} $CFLAGS -xc - -o /dev/null -Wl,--as-needed -l$i > /dev/null 2>/dev/null &&
-  echo -l$i >> generated/optlibs.dat
-  echo -n .
-done
-echo
+[ ! -z "$NOBUILD" ] && exit 0
 
 echo -n "Compile toybox"
 [ ! -z "$V" ] && echo
-
-# Extract a list of toys/*/*.c files to compile from the data in $KCONFIG_CONFIG
-
-TOYFILES="$(egrep -l "TOY[(]($(sed -n 's/^CONFIG_\([^=]*\)=.*/\1/p' "$KCONFIG_CONFIG" | xargs | tr ' [A-Z]' '|[a-z]'))[ ,]" toys/*/*.c)"
-
-do_loudly()
-{
-  [ ! -z "$V" ] && echo "$@" || echo -n .
-  "$@"
-}
-
-BUILD="$(echo ${CROSS_COMPILE}${CC} $CFLAGS -I . $OPTIMIZE)"
-FILES="$(echo lib/*.c main.c $TOYFILES)"
-LINK="$(echo $LDOPTIMIZE -o toybox_unstripped -Wl,--as-needed $(cat generated/optlibs.dat))"
+DOTPROG=.
 
 # This is a parallel version of: do_loudly $BUILD $FILES $LINK || exit 1
 
-# Write a canned build line for use on crippled build machines.
-(
-  echo "#!/bin/sh"
-  echo
-  echo "BUILD=\"$BUILD\""
-  echo
-  echo "LINK=\"$LINK\""
-  echo
-  echo "FILES=\"$FILES\""
-  echo
-  echo '$BUILD $FILES $LINK'
-) > generated/build.sh && chmod +x generated/build.sh || echo 1
-
-rm -rf generated/obj && mkdir -p generated/obj || exit 1
+X="$(ls -1t generated/obj/* 2>/dev/null | tail -n 1)"
+if [ ! -e "$X" ] || [ ! -z "$(find toys -name "*.h" -newer "$X")" ]
+then
+  rm -rf generated/obj && mkdir -p generated/obj || exit 1
+else
+  rm -f generated/obj/{main,lib_help}.o || exit 1
+fi
 PENDING=
+LFILES=
 for i in $FILES
 do
   # build each generated/obj/*.o file in parallel
 
   X=${i/lib\//lib_}
   X=${X##*/}
-  do_loudly $BUILD -c $i -o generated/obj/${X%%.c}.o &
+  OUT="generated/obj/${X%%.c}.o"
+  LFILES="$LFILES $OUT"
+  [ "$OUT" -nt "$i" ] && continue
+  do_loudly $BUILD -c $i -o $OUT &
 
   # ratelimit to $CPUS many parallel jobs, detecting errors
 
@@ -220,7 +260,7 @@ do
   wait $i || exit 1
 done
 
-do_loudly $BUILD generated/obj/*.o $LINK || exit 1
+do_loudly $BUILD $LFILES $LINK || exit 1
 do_loudly ${CROSS_COMPILE}${STRIP} toybox_unstripped -o toybox || exit 1
 # gcc 4.4's strip command is buggy, and doesn't set the executable bit on
 # its output the way SUSv4 suggests it do so.