android - (Android4.2)random compile error "unrecognized command line option '-mshort-load-bytes'" with arm-eabi-gcc 4.6.x -

i have ported u-boot android4.2 source , use android toolchain, has gcc version 4.6.x-google 20120106.

my environment build: ubuntu 10.04, host gcc version 4.4.3.

my platform arm-v7, cotex-a5.

the problem u-boot encounter following compile error (i use multijob building android):

target thumb c++: libgles_trace <= frameworks/native/opengl/libs/gles_trace/src/gltrace_context.cpp      cc  ispi.c  target thumb c++: libgles_trace <= frameworks/native/opengl/libs/gles_trace/src/gltrace_egl.cpp      cc  spl.c  target thumb c++: libgles_trace <= frameworks/native/opengl/libs/gles_trace/src/gltrace_eglapi.cpp      make    arch/arm/lib/     cc  timer.c cc1: error: unrecognized command line option '-mshort-load-bytes'  make[2]: *** [/home/jenkins/workspace/droid-4.2.2_r1/out/target/product/aere/obj/u-boot/arch/arm/cpu/armv7/rda/timer.o] error 1  make[1]: *** [/home/jenkins/workspace/droid-4.2.2_r1/out/target/product/aere/obj/u-boot/arch/arm/cpu/armv7/rda/librda.o] error 2  make[1]: leaving directory `/home/jenkins/workspace/rdadroid-4.2.2_r1/u-boot' make: *** [out/target/product/aere/obj/u-boot/u-boot.img] error 2  make: *** waiting unfinished jobs.... 

but if build again, compile error disappears。

i know gcc after 3.5 doesn't support -mshort-load-bytes option, gcc-version 4.6, , checked include/generated/cc_options.mk, if build fails, content is:

cc_options += -marm cc_options += -mno-thumb-interwork cc_options += -mabi=apcs-gnu cc_options += -mabi=aapcs-linux cc_options += -march=armv7-a cc_options += -fno-stack-protector cc_options += -wno-format-nonliteral cc_options += -wno-format-security cc_options += -fstack-usage cc_options += -fno-toplevel-reorder cc_options += -mshort-load-bytes 

if success, there no cc_options += -mshort-load-bytes.

so, can tell me how debug problems? thank you!

-mshort-load-bytes old option has been replaced in gcc 3 -malignment-traps. matters old versions of arm architecture, before armv4. tells gcc not load short (2 byte) values loading words (4 byte) values unaligned location, because cause alignment trap.

references: gcc 3.0.2 , gcc 2.95.3 docs.