generate_BUFSIZ.sh: yet another tweak

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

2 files changed, 42 insertions, 13 deletions

diff --git a/include/.gitignore b/include/.gitignore
index 9d9b6c499..75afff9ca 100644
--- a/include/.gitignore
+++ b/include/.gitignore
@@ -8,3 +8,4 @@
 /NUM_APPLETS.h
 /usage_compressed.h
 /usage.h
+/common_bufsiz.h*
diff --git a/scripts/generate_BUFSIZ.sh b/scripts/generate_BUFSIZ.sh
index 750fedbef..844261906 100755
--- a/scripts/generate_BUFSIZ.sh
+++ b/scripts/generate_BUFSIZ.sh
@@ -6,6 +6,7 @@
 . ./.config || exit 1
 
 debug=false
+#debug=true
 
 postcompile=false
 test x"$1" = x"--post" && { postcompile=true; shift; }
@@ -62,6 +63,11 @@ generate_malloc_and_exit() {
         $exitcmd
 }
 
+round_down_COMMON_BUFSIZE() {
+        COMMON_BUFSIZE=$(( ($1-32) & 0xfffffe0 ))
+        COMMON_BUFSIZE=$(( COMMON_BUFSIZE < 1024 ? 1024 : COMMON_BUFSIZE ))
+}
+
 # User does not want any funky stuff?
 test x"$CONFIG_FEATURE_USE_BSS_TAIL" = x"y" || generate_std_and_exit
 
@@ -102,22 +108,43 @@ if $postcompile; then
 
         # How much space between _end[] and next page?
         PAGE_MASK=$((PAGE_SIZE-1))
-        COMMON_BUFSIZE=$(( (-END) & PAGE_MASK ))
-        echo "COMMON_BUFSIZE = $COMMON_BUFSIZE bytes"
+        TAIL_SIZE=$(( (-END) & PAGE_MASK ))
+        $debug && echo "TAIL_SIZE:$TAIL_SIZE bytes"
 
-        if test x"$method" != x"malloc"; then
-                if test $COMMON_BUFSIZE -lt 1024; then
+        if test x"$method" = x"1k" || test x"$method" = x"big"; then
+                if test $TAIL_SIZE -lt 1024; then
                         # _end[] has no enough space for bb_common_bufsiz1[]
+                        echo "Warning! Space in _end[] is too small ($TAIL_SIZE bytes)!"
+                        echo "Rerun make to build a binary which doesn't use it!"
                         rm -- "$common_bufsiz_h.1k.OK" 2>/dev/null
                         { md5sum <.config | cut -d' ' -f1; stat -c "%Y" .config; } >"$common_bufsiz_h.1k.FAIL"
-                        echo "Warning! Space in _end[] is too small ($COMMON_BUFSIZE bytes)!"
-                        echo "Rerun make to build a binary which doesn't use it!"
-                        rm busybox_unstripped busybox
+                        rm busybox_unstripped busybox 2>/dev/null
+# Note: here we can do either a "malloc" or "std" build.
+# "malloc" gives a bit bigger code:
+#     text  bss filename
+#   804355 5385 busybox.std
+#   804618 4361 busybox.malloc
+# but may have a smaller .bss (not guaranteed!). Use "pmap -x" to verify.
                         exitcmd="exit 1"
+                        generate_malloc_and_exit
                 else
+                        PREV_SIZE=1024
+                        test x"$method" = x"big" && PREV_SIZE=`cat -- "$common_bufsiz_h.1k.OK"`
+                        round_down_COMMON_BUFSIZE $PREV_SIZE
+                        PREV_BUFSIZE=$COMMON_BUFSIZE
+
                         rm -- "$common_bufsiz_h.1k.FAIL" 2>/dev/null
-                        echo $COMMON_BUFSIZE >"$common_bufsiz_h.1k.OK"
-                        test $COMMON_BUFSIZE -gt $((1024+32)) && echo "Rerun make to use larger COMMON_BUFSIZE"
+                        echo $TAIL_SIZE >"$common_bufsiz_h.1k.OK"
+                        round_down_COMMON_BUFSIZE $TAIL_SIZE
+                        # emit message only if COMMON_BUFSIZE is indeed larger
+                        test $COMMON_BUFSIZE -gt $PREV_BUFSIZE \
+                                && echo "Rerun make to use larger COMMON_BUFSIZE ($COMMON_BUFSIZE)"
+#TODO: test $PREV_BUFSIZE -lt $TAIL_SIZE && PANIC!!!
+#Code size with COMMON_BUFSIZE > 1024 may be bigger than code with COMMON_BUFSIZE = 1024!
+#(currently we just hope "-32 and round down to 32" saves us)
+
+                        test $COMMON_BUFSIZE = 1024 && generate_1k_and_exit
+                        generate_big_and_exit $COMMON_BUFSIZE "big"
                 fi
         fi
 fi
@@ -127,13 +154,12 @@ fi
 if test -f "$common_bufsiz_h.1k.OK"; then
         # Previous build succeeded fitting 1k into _end[].
         # Try bigger COMMON_BUFSIZE if possible.
-        COMMON_BUFSIZE=`cat -- "$common_bufsiz_h.1k.OK"`
-        # Round down a bit
-        COMMON_BUFSIZE=$(( (COMMON_BUFSIZE-32) & 0xfffffe0 ))
-        COMMON_BUFSIZE=$(( COMMON_BUFSIZE < 1024 ? 1024 : COMMON_BUFSIZE ))
+        TAIL_SIZE=`cat -- "$common_bufsiz_h.1k.OK"`
+        round_down_COMMON_BUFSIZE $TAIL_SIZE
         test $COMMON_BUFSIZE = 1024 && generate_1k_and_exit
         generate_big_and_exit $COMMON_BUFSIZE "big"
 fi
+
 if test -f "$common_bufsiz_h.1k.FAIL"; then
         # Previous build FAILED to fit 1k into _end[].
         # Was it with same .config?
@@ -142,6 +168,7 @@ if test -f "$common_bufsiz_h.1k.FAIL"; then
         # If yes, then build a "malloced" version
         if test x"$oldcfg" = x"$curcfg"; then
                 echo "Will not try 1k build, it failed before. Touch .config to override"
+# Note: here we can do either a "malloc" or "std" build.
                 generate_malloc_and_exit
         fi
         # else: try 1k version
@@ -149,5 +176,6 @@ if test -f "$common_bufsiz_h.1k.FAIL"; then
         rm -- "$common_bufsiz_h.1k.FAIL"
         generate_1k_and_exit
 fi
+
 # There was no 1k build yet. Try it.
 generate_1k_and_exit