build system: -fno-builtin-printf
Benefits are: drops reference to out-of-line putchar(), fixes a few cases
of failed string merge.
function old new delta
i2cdump_main 1488 1502 +14
sha256_process_block64 423 433 +10
sendmail_main 1183 1185 +2
list_table 1114 1116 +2
i2cdetect_main 1235 1237 +2
fdisk_main 2852 2854 +2
builtin_type 119 121 +2
unicode_conv_to_printable2 325 324 -1
scan_recursive 380 378 -2
mkfs_minix_main 2687 2684 -3
buffer_fill_and_print 178 169 -9
putchar 152 - -152
------------------------------------------------------------------------------
(add/remove: 0/2 grow/shrink: 7/4 up/down: 34/-167) Total: -133 bytes
text data bss dec hex filename
937788 932 17676 956396 e97ec busybox_old
937564 932 17676 956172 e970c busybox_unstripped
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
diff --git a/Makefile.flags b/Makefile.flags
index 2bc83d1..b6cd32e 100644
--- a/Makefile.flags
+++ b/Makefile.flags
@@ -56,6 +56,9 @@
# Defeat .eh_frame bloat (gcc 4.6.3 x86-32 defconfig: 20% smaller busybox binary):
CFLAGS += $(call cc-option,-fno-unwind-tables,)
CFLAGS += $(call cc-option,-fno-asynchronous-unwind-tables,)
+# No automatic printf->puts,putchar conversions
+# (try disabling this and comparing assembly, it's instructive)
+CFLAGS += $(call cc-option,-fno-builtin-printf,)
# FIXME: These warnings are at least partially to be concerned about and should
# be fixed..