Contrary to the comment "newer gccs do it by default", newer gcc
versions default to -maccumulate-outgoing-args only with
CONFIG_CC_OPTIMIZE_FOR_SIZE=n, and then only with some CPU settings.
Measured with an i386 defconfig, gcc 4.2.1 and kernel 2.6.23-rc1
("orig" is the plain kernel, "changed is with -maccumulate-outgoing-args
removed):
$ ls -la vmlinux*
-rwxrwxr-x 1 bunk bunk 6269713 2007-07-24 22:19 vmlinux.changed
-rwxrwxr-x 1 bunk bunk 6425361 2007-07-24 22:19 vmlinux.orig
$ size vmlinux.*
text data bss dec hex filename
4493465 504108 614400 5611973 55a1c5 vmlinux.changed
4646160 504108 614400 5764668 57f63c vmlinux.orig
$
That's a 2.5% size increase that does for sure hurt small systems.
If the stack unwinder ever comes back and needs this as indicated in the
comment, adding it to the cflags when the user enabled the unwinder
should be a better option.
Signed-off-by: Adrian Bunk <[email protected]>
---
--- linux-2.6.22-rc6-mm1/arch/i386/Makefile.old 2007-07-24 22:29:56.000000000 +0200
+++ linux-2.6.22-rc6-mm1/arch/i386/Makefile 2007-07-24 22:30:16.000000000 +0200
@@ -42,10 +42,6 @@
# temporary until string.h is fixed
cflags-y += -ffreestanding
-# this works around some issues with generating unwind tables in older gccs
-# newer gccs do it by default
-cflags-y += -maccumulate-outgoing-args
-
# Disable unit-at-a-time mode on pre-gcc-4.0 compilers, it makes gcc use
# a lot more stack due to the lack of sharing of stacklots:
CFLAGS += $(shell if [ $(call cc-version) -lt 0400 ] ; then echo $(call cc-option,-fno-unit-at-a-time); fi ;)
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
[Index of Archives]
[Kernel Newbies]
[Netfilter]
[Bugtraq]
[Photo]
[Stuff]
[Gimp]
[Yosemite News]
[MIPS Linux]
[ARM Linux]
[Linux Security]
[Linux RAID]
[Video 4 Linux]
[Linux for the blind]
[Linux Resources]
