Patchwork [U-Boot,6/7,v2] POWERPC: enable --gc-sections and -ffunction-sections -fdata-sections

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Submitter Wolfgang Denk
Date Nov. 22, 2010, 7:10 a.m.
Message ID <1290409815-7035-1-git-send-email-wd@denx.de>
Download mbox | patch
Permalink /patch/72505/
State Superseded
Headers show

Comments

Wolfgang Denk - Nov. 22, 2010, 7:10 a.m.
The switch from archive libraries to partial linking has introduced a
number of problems, that are non-trivial to solve.  For example, it is
no longer possible to include individual object files in the linker
script as we did before for example in the case of boards with
embedded environment to fill up the gap caused by the need to align
the environment on flash erase block boundaries.

The best (but unfortunately not easiest) approach to address this
problem is to enable -ffunction-sections (and -fdata-sections) so
we can again (and even in much finer granularity) place certain code
where we want it.  When doing this step, it seems only consequent to
also add --gc-sections which has the added benefit of reducing the
memory footprint of the U-Boot image (both in flash and in RAM).

Unfortunately, this requires changes to a lot of linker scripts.

Signed-off-by: Wolfgang Denk <wd@denx.de>
Cc: Stefan Roese <sr@denx.de>
---
v2:	- fix copy & p[aste error in commit message
	- remove now duplicated options for 85xx and 86xx

 arch/powerpc/config.mk             |    4 ++--
 arch/powerpc/cpu/mpc85xx/config.mk |    4 ----
 arch/powerpc/cpu/mpc86xx/config.mk |    4 ----
 3 files changed, 2 insertions(+), 10 deletions(-)

Patch

diff --git a/arch/powerpc/config.mk b/arch/powerpc/config.mk
index 8cf2279..271409f 100644
--- a/arch/powerpc/config.mk
+++ b/arch/powerpc/config.mk
@@ -25,9 +25,9 @@  CROSS_COMPILE ?= ppc_8xx-
 
 STANDALONE_LOAD_ADDR = 0x40000
 
-PLATFORM_RELFLAGS += -mrelocatable
+PLATFORM_RELFLAGS += -mrelocatable -ffunction-sections -fdata-sections
 PLATFORM_CPPFLAGS += -DCONFIG_PPC -D__powerpc__
-PLATFORM_LDFLAGS  += -n
+PLATFORM_LDFLAGS  += -n --gc-sections
 
 ifdef CONFIG_SYS_LDSCRIPT
 # need to strip off double quotes
diff --git a/arch/powerpc/cpu/mpc85xx/config.mk b/arch/powerpc/cpu/mpc85xx/config.mk
index ce4376b..f07d920 100644
--- a/arch/powerpc/cpu/mpc85xx/config.mk
+++ b/arch/powerpc/cpu/mpc85xx/config.mk
@@ -25,10 +25,6 @@  PLATFORM_RELFLAGS += -fPIC -meabi
 
 PLATFORM_CPPFLAGS += -ffixed-r2 -Wa,-me500 -msoft-float -mno-string
 
-# Enable gc-sections to enable generation of smaller images.
-PLATFORM_LDFLAGS += --gc-sections
-PLATFORM_RELFLAGS += -ffunction-sections -fdata-sections
-
 # -mspe=yes is needed to have -mno-spe accepted by a buggy GCC;
 # see "[PATCH,rs6000] make -mno-spe work as expected" on
 # http://gcc.gnu.org/ml/gcc-patches/2008-04/msg00311.html
diff --git a/arch/powerpc/cpu/mpc86xx/config.mk b/arch/powerpc/cpu/mpc86xx/config.mk
index bce0fb3..7fae7e4 100644
--- a/arch/powerpc/cpu/mpc86xx/config.mk
+++ b/arch/powerpc/cpu/mpc86xx/config.mk
@@ -26,9 +26,5 @@  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