[avr-gcc-list] -ffunction-sections and xmega

[Thomas Ingebretsen]

Hi!
In an attempt to reduce the code size I tried to use the
-ffunction-sections and -fdata-sections with the --gc-sections linker
flag.
With -ffunction-sections option enabled the linker fails with the
following errors:

avr-gcc -Wl,-Map,orient.out.map -mmcu=atxmega32a4 --gc-sections
-Wl,--relax -lc -lm -o orient.out main.o kalman.o data_link.o
gps_parser.o ../common/ring.o ../common/stack.o ../common/crc16.o
../common/runge_kutta.o ../common/trig.o ../common/coordinates.o
hal/acc.o hal/adc.o hal/baro.o hal/gps.o hal/gyro.o hal/orient_hal.o
hal/mag.o hal/temp.o hal/hw/lpr530al.o hal/hw/ly530alh.o
hal/hw/mma7260q.o hal/hw/venus634flpx.o hal/cdev.o
../common/hal/timing.o ../common/hal/xmega_usart.o
../common/hal/xmega_adc.o ../common/hal/xmega_clock.o

/usr/lib/gcc/avr/4.3.4/../../../avr/lib/avrxmega3/libc.a(fp_powsodd.o):../../../libm/fplib/fp_powsodd.S:59:
relocation truncated to fit: R_AVR_13_PCREL against symbol `__mulsf3'
defined in .text section in
/usr/lib/gcc/avr/4.3.4/avrxmega3/libgcc.a(_mul_sf.o)
/usr/lib/gcc/avr/4.3.4/../../../avr/lib/avrxmega3/libc.a(fp_powsodd.o):../../../libm/fplib/fp_powsodd.S:69:
relocation truncated to fit: R_AVR_13_PCREL against symbol `__mulsf3'
defined in .text section in
/usr/lib/gcc/avr/4.3.4/avrxmega3/libgcc.a(_mul_sf.o)
/usr/lib/gcc/avr/4.3.4/../../../avr/lib/avrxmega3/libc.a(inverse.o):../../../libm/fplib/inverse.S:50:
relocation truncated to fit: R_AVR_13_PCREL against symbol `__divsf3'
defined in .text section in
/usr/lib/gcc/avr/4.3.4/avrxmega3/libgcc.a(_div_sf.o)
make: *** [orient.out] Error 1


CFLAGS=-I. $(INC) -g $(MMCU) -O$(OPTLEVEL)      \
        -fpack-struct -fshort-enums             \
        -funsigned-bitfields -funsigned-char    \
        -Wall -Wstrict-prototypes               \
        $(SIM)                                  \
        -Wa,-ahlms=$(firstword                  \
        $(filter %.lst, $(<:.c=.lst)))          \
        --param inline-call-cost=2              \
        -finline-limit=3                        \
        -fno-inline-small-functions             \
        -fdata-sections                         \
        -ffreestanding                          \
        -ffunction-sections                     \

LDFLAGS=-Wl,-Map,$(TRG).map $(MMCU)     \
        --gc-sections                   \
        -Wl,--relax                     \
         $(LIBS)

-- 
Regards,
Thomas