[U-Boot] [PATCH 16/17] 86xx: Use gc-sections to reduce image size

Peter Tyser
2010-09-29T19:05:55Z

On an XPedite5170 over 11KBytes were saved:
Before:
text data bss dec hex filename
319488 28700 33204 381392 5d1d0 ./u-boot

After:
text data bss dec hex filename
307663 29144 33204 370011 5a55b ./u-boot

Signed-off-by: Peter Tyser <ptyser@xes-inc.com>
CC: Kumar Gala <galak@kernel.crashing.org>
---
arch/powerpc/cpu/mpc86xx/config.mk | 4 ++++
arch/powerpc/cpu/mpc86xx/u-boot.lds | 26 ++++++++------------------
2 files changed, 12 insertions(+), 18 deletions(-)

diff --git a/arch/powerpc/cpu/mpc86xx/config.mk b/arch/powerpc/cpu/mpc86xx/config.mk
index 7fae7e4..bce0fb3 100644
--- a/arch/powerpc/cpu/mpc86xx/config.mk
+++ b/arch/powerpc/cpu/mpc86xx/config.mk
@@ -26,5 +26,9 @@ PLATFORM_RELFLAGS += -fPIC -meabi
PLATFORM_CPPFLAGS += -ffixed-r2 -mstring
PLATFORM_CPPFLAGS += -maltivec -mabi=altivec -msoft-float

+# Enable gc-sections to enable generation of smaller images.
+PLATFORM_LDFLAGS += --gc-sections
+PLATFORM_RELFLAGS += -ffunction-sections -fdata-sections
+
# Use default linker script. Board port can override in board/*/config.mk
LDSCRIPT := $(SRCTREE)/arch/powerpc/cpu/mpc86xx/u-boot.lds
diff --git a/arch/powerpc/cpu/mpc86xx/u-boot.lds b/arch/powerpc/cpu/mpc86xx/u-boot.lds
index 4cea3b3..4bfcb90 100644
--- a/arch/powerpc/cpu/mpc86xx/u-boot.lds
+++ b/arch/powerpc/cpu/mpc86xx/u-boot.lds
@@ -60,19 +60,14 @@ SECTIONS
lib/crc32.o (.text)
arch/powerpc/lib/extable.o (.text)
lib/zlib.o (.text)
- *(.text)
- *(.got1)
+ *(.text*)
}
_etext = .;
PROVIDE (etext = .);
.rodata :
{
- *(.eh_frame)
*(SORT_BY_ALIGNMENT(SORT_BY_NAME(.rodata*)))
}
- .fini : { *(.fini) } =0
- .ctors : { *(.ctors) }
- .dtors : { *(.dtors) }

/* Read-write section, merged into data segment: */
. = (. + 0x00FF) & 0xFFFFFF00;
@@ -80,23 +75,19 @@ SECTIONS
PROVIDE (erotext = .);
.reloc :
{
- *(.got)
+ KEEP(*(.got))
_GOT2_TABLE_ = .;
- *(.got2)
+ KEEP(*(.got2))
_FIXUP_TABLE_ = .;
- *(.fixup)
+ KEEP(*(.fixup))
}
__got2_entries = (_FIXUP_TABLE_ - _GOT2_TABLE_) >> 2;
__fixup_entries = (. - _FIXUP_TABLE_) >> 2;

.data :
{
- *(.data)
- *(.data1)
- *(.sdata)
- *(.sdata2)
- *(.dynamic)
- CONSTRUCTORS
+ *(.data*)
+ *(.sdata*)
}
_edata = .;
PROVIDE (edata = .);
@@ -121,9 +112,8 @@ SECTIONS
__bss_start = .;
.bss (NOLOAD) :
{
- *(.sbss) *(.scommon)
- *(.dynbss)
- *(.bss)
+ *(.sbss*)
+ *(.bss*)
*(COMMON)
. = ALIGN(4);
}
--
1.7.0.4