Re: arm-elf:thumb and exception

[tanaka <tanaka at personal-media dot co dot jp>]

Thank you!

>Does the application work if you build all the code in Thumb?  You
>currently have a mix of ARM and Thumb code.

Yes. The sample works fine, when all of the modules were compiled in Thumb.

>3) Edit the file t-arm-elf
>4) Uncomment the following 3 lines
>
>MULTILIB_OPTIONS    += mno-thumb-interwork/mthumb-interwork
>MULTILIB_DIRNAMES   += normal interwork
>MULTILIB_EXCEPTIONS += *mapcs-26/*mthumb-interwork*

Yes. These operations had been already done.

I wonder,
mov pc, r1
is used when return to each catch from the tail of 
_Unwind_SjLj_RaiseException.
The LSB of the value of the r1 is 0.
It means that, the mode is not changed to Thumb from Arm.
But it is not all of the problem.

Following is the log of the compile message.
------------------------------------
tanaka@r48:/u9/te/util/c++test/bad/thumb_exp/arm-elf2/$ ./mk2.rc
/work/linux/tool/Linux-i686/bin/arm-unknown-elf-gcc -g -O0 -c 
-mthumb-interwork ../src/arm/crt0.S -o crt0.o
/work/linux/tool/Linux-i686/bin/arm-unknown-elf-gcc -g -O0 -c 
-mthumb-interwork ../src/arm/arm.S -o arm.o
/work/linux/tool/Linux-i686/bin/arm-unknown-elf-gcc -g -O0 -c 
-mthumb-interwork ../src/startup.c -o startup.o
/work/linux/tool/Linux-i686/bin/arm-unknown-elf-g++ -g -O0 -c 
-mthumb-interwork ../src/exp16bit.cc -o exp16bit.o -I../src
/work/linux/tool/Linux-i686/bin/arm-unknown-elf-g++ -g -O0 -c 
-mthumb-interwork -mthumb ../src/expon16.cc -o expon16.o -I../src
/work/linux/tool/Linux-i686/bin/arm-unknown-elf-g++ -g -O0 -c 
-mthumb-interwork ../src/expon32.cc -o expon32.o -I../src
/work/linux/tool/Linux-i686/bin/arm-unknown-elf-gcc -g -O0 -c 
-mthumb-interwork ../src/misc.c -o misc.o -I../src
../src/misc.c:17: warning: conflicting types for built-in function `memset'
../src/misc.c: In function `abort':
../src/misc.c:25: warning: `noreturn' function does return

/work/linux/tool/Linux-i686/bin/arm-unknown-elf-g++ -mthumb-interwork 
-Wl,-verbose -nostartfiles -nostdlib -o exp16bit crt0.o 
/work/linux/tool/Linux-i686/lib/gcc-lib/arm-unknown-elf/3.3.2/interwork/crti.o 
/work/linux/tool/Linux-i686/lib/gcc-lib/arm-unknown-elf/3.3.2/interwork/crtbegin.o 
arm.o startup.o exp16bit.o expon32.o expon16.o misc.o 
/work/linux/tool/Linux-i686/arm-unknown-elf/lib/interwork/libsupc++.a 
/work/linux/tool/Linux-i686/lib/gcc-lib/arm-unknown-elf/3.3.2/interwork/libgcc.a 
/work/linux/tool/Linux-i686/lib/gcc-lib/arm-unknown-elf/3.3.2/interwork/crtend.o 
/work/linux/tool/Linux-i686/lib/gcc-lib/arm-unknown-elf/3.3.2/interwork/crtn.o
GNU ld version 2.14 20030612
  Supported emulations:
   armelf
using internal linker script:
==================================================
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==================================================
attempt to open crt0.o succeeded
crt0.o
attempt to open 
/work/linux/tool/Linux-i686/lib/gcc-lib/arm-unknown-elf/3.3.2/interwork/crti.o 
succeeded
/work/linux/tool/Linux-i686/lib/gcc-lib/arm-unknown-elf/3.3.2/interwork/crti.o
attempt to open 
/work/linux/tool/Linux-i686/lib/gcc-lib/arm-unknown-elf/3.3.2/interwork/crtbegin.o 
succeeded
/work/linux/tool/Linux-i686/lib/gcc-lib/arm-unknown-elf/3.3.2/interwork/crtbegin.o
attempt to open arm.o succeeded
arm.o
attempt to open startup.o succeeded
startup.o
attempt to open exp16bit.o succeeded
exp16bit.o
attempt to open expon32.o succeeded
expon32.o
attempt to open expon16.o succeeded
expon16.o
attempt to open misc.o succeeded
misc.o
attempt to open 
/work/linux/tool/Linux-i686/arm-unknown-elf/lib/interwork/libsupc++.a 
succeeded
(/work/linux/tool/Linux-i686/arm-unknown-elf/lib/interwork/libsupc++.a)eh_alloc.o
(/work/linux/tool/Linux-i686/arm-unknown-elf/lib/interwork/libsupc++.a)eh_catch.o
(/work/linux/tool/Linux-i686/arm-unknown-elf/lib/interwork/libsupc++.a)eh_globals.o
(/work/linux/tool/Linux-i686/arm-unknown-elf/lib/interwork/libsupc++.a)eh_personality.o
(/work/linux/tool/Linux-i686/arm-unknown-elf/lib/interwork/libsupc++.a)eh_terminate.o
(/work/linux/tool/Linux-i686/arm-unknown-elf/lib/interwork/libsupc++.a)eh_throw.o
(/work/linux/tool/Linux-i686/arm-unknown-elf/lib/interwork/libsupc++.a)tinfo.o
(/work/linux/tool/Linux-i686/arm-unknown-elf/lib/interwork/libsupc++.a)del_op.o
(/work/linux/tool/Linux-i686/arm-unknown-elf/lib/interwork/libsupc++.a)eh_exception.o
attempt to open 
/work/linux/tool/Linux-i686/lib/gcc-lib/arm-unknown-elf/3.3.2/interwork/libgcc.a 
succeeded
(/work/linux/tool/Linux-i686/lib/gcc-lib/arm-unknown-elf/3.3.2/interwork/libgcc.a)unwind-sjlj.o
attempt to open 
/work/linux/tool/Linux-i686/lib/gcc-lib/arm-unknown-elf/3.3.2/interwork/crtend.o 
succeeded
/work/linux/tool/Linux-i686/lib/gcc-lib/arm-unknown-elf/3.3.2/interwork/crtend.o
attempt to open 
/work/linux/tool/Linux-i686/lib/gcc-lib/arm-unknown-elf/3.3.2/interwork/crtn.o 
succeeded
/work/linux/tool/Linux-i686/lib/gcc-lib/arm-unknown-elf/3.3.2/interwork/crtn.o

tanaka@r48:/u9/te/util/c++test/bad/thumb_exp/arm-elf2/$
------------------------------------

regards.
t_tanaka


Richard Earnshaw wrote:
> > Hello.
> >
> > I have a question. Does Arm's thumb instruction set support the
> > exception of C++?
> > The follwing sample code does not run correctly.
> >
> > The program counter does not reach to the tail of the main(), even on
> > the simulator of the gdb.
> > When all of the modules of the sample are compiled as arm instruction
> > set, The sample runs OK.
>
>
> Does the application work if you build all the code in Thumb?  You 
> currently have a mix of ARM and Thumb code.
>
> My suspicion is that you aren't picking up the interworking libraries 
> correctly.  To get these you normally have to edit a source file in the 
> compiler to allow these to be built:
>
> 1) Unpack the gcc source tree.
> 2) Go to the gcc/config/arm subdirectory
> 3) Edit the file t-arm-elf
> 4) Uncomment the following 3 lines
>
> MULTILIB_OPTIONS    += mno-thumb-interwork/mthumb-interwork
> MULTILIB_DIRNAMES   += normal interwork
> MULTILIB_EXCEPTIONS += *mapcs-26/*mthumb-interwork*
>
> 5) Rebuild and reinstall your compiler.
>
> One final point.  When you link your application, you must also use 
> -mthumb-interwork or gcc will pick the wrong libraries.  You should also 
> use g++ for linking if your application has C++ code.  Hence:
>
> /work/linux/tool/Linux-i686/bin/arm-unknown-elf-g++ -mthumb-interwork -o 
> exp16bit
> exp16bit.o expon32.o expon16.o misc.o
>
> You can also choose between libraries containing ARM or Thumb code by 
> passing the option -mthumb when linking.
>
> R. 



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