llvm dev - Jun 2016 - llvm-bjdump and ELF-ARM/Thumb

Hi Everyone,

When I used llvm-objdump to disassemble an ELF armv7 or thumb I have this error
message:

llvm-objdump: warning: invalid instruction encoding

This message appears directly into the output and the output is mostly wrong
(the invalid instruction create a shift in the addresses) :


    1a6d:	ff 2f e1 08 	stmeq	r1!, {r0, r1, r2, r3, r4, r5, r6, r7, r8, r9, r10,
r11, sp} ^
    1a71:	30 90 e5 00 	rsceq	r9, r5, r0, lsr r0
    1a75:	10 a0 e1 00 	rsceq	r10, r1, r0, lsl r0
    1a79:	00 53 e3 1e 	cdpne	p3, #14, c5, c3, c0, #0
llvm-objdump: warning: invalid instruction encoding
    1a7e:	2f 01 01 00 	andeq	r0, r1, pc, lsr #2
llvm-objdump: warning: invalid instruction encoding
    1a83:	e3 13 ff 2f 	svchs	#16716771
llvm-objdump: warning: invalid instruction encoding

The binaries I try to read are c++ dynamic libraries for Android.

I have used the following parameters:

-llvm-objcdump mylib.so -d -arch=arm
-llvm-objcdump mylib.so -d -arch=armv7
-llvm-objcdump mylib.so -d -arch=thumb

or with the following triples:

armv7-none-linux-android
thumbv7-none-linux-android

Does anyone know why I have this error? Am I missing some input parameters?

This is strange because it works great on iOS binaries (both thumb or arm).

Greetings,

Johan

What happens if you use the standard bunutils objdump e.g. from macports
package arm-elf-binutils (if you're on a Mac)?


On Mon, Jun 20, 2016 at 12:45 AM, Johan Wehrli via llvm-dev <
llvm-dev at lists.llvm.org> wrote:
> Hi Everyone,
>
> When I used llvm-objdump to disassemble an ELF armv7 or thumb I have this
> error message:
>
> llvm-objdump: warning: invalid instruction encoding
>
> This message appears directly into the output and the output is mostly
> wrong (the invalid instruction create a shift in the addresses) :
>
>
>     1a6d:       ff 2f e1 08     stmeq   r1!, {r0, r1, r2, r3, r4, r5, r6,
> r7, r8, r9, r10, r11, sp} ^
>     1a71:       30 90 e5 00     rsceq   r9, r5, r0, lsr r0
>     1a75:       10 a0 e1 00     rsceq   r10, r1, r0, lsl r0
>     1a79:       00 53 e3 1e     cdpne   p3, #14, c5, c3, c0, #0
> llvm-objdump: warning: invalid instruction encoding
>     1a7e:       2f 01 01 00     andeq   r0, r1, pc, lsr #2
> llvm-objdump: warning: invalid instruction encoding
>     1a83:       e3 13 ff 2f     svchs   #16716771
> llvm-objdump: warning: invalid instruction encoding
>
> The binaries I try to read are c++ dynamic libraries for Android.
>
> I have used the following parameters:
>
> -llvm-objcdump mylib.so -d -arch=arm
> -llvm-objcdump mylib.so -d -arch=armv7
> -llvm-objcdump mylib.so -d -arch=thumb
>
> or with the following triples:
>
> armv7-none-linux-android
> thumbv7-none-linux-android
>
> Does anyone know why I have this error? Am I missing some input parameters?
>
> This is strange because it works great on iOS binaries (both thumb or arm).
>
> Greetings,
>
> Johan
> _______________________________________________
> LLVM Developers mailing list
> llvm-dev at lists.llvm.org
> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
>
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The standard objdump does not recognised the format.

It works if I used an arm-linux-androideabi-objdump from the Android ndk but I
am using the clang API to read binary inside my soft.

This is why I was only working with llvm-objdump.
> On 19 Jun 2016, at 15:03, Bruce Hoult <bruce at hoult.org> wrote:
> 
> What happens if you use the standard bunutils objdump e.g. from macports
package arm-elf-binutils (if you're on a Mac)?
> 
> 
> On Mon, Jun 20, 2016 at 12:45 AM, Johan Wehrli via llvm-dev <llvm-dev at
lists.llvm.org <mailto:llvm-dev at lists.llvm.org>> wrote:
> Hi Everyone,
> 
> When I used llvm-objdump to disassemble an ELF armv7 or thumb I have this
error message:
> 
> llvm-objdump: warning: invalid instruction encoding
> 
> This message appears directly into the output and the output is mostly
wrong (the invalid instruction create a shift in the addresses) :
> 
> 
>     1a6d:       ff 2f e1 08     stmeq   r1!, {r0, r1, r2, r3, r4, r5, r6,
r7, r8, r9, r10, r11, sp} ^
>     1a71:       30 90 e5 00     rsceq   r9, r5, r0, lsr r0
>     1a75:       10 a0 e1 00     rsceq   r10, r1, r0, lsl r0
>     1a79:       00 53 e3 1e     cdpne   p3, #14, c5, c3, c0, #0
> llvm-objdump: warning: invalid instruction encoding
>     1a7e:       2f 01 01 00     andeq   r0, r1, pc, lsr #2
> llvm-objdump: warning: invalid instruction encoding
>     1a83:       e3 13 ff 2f     svchs   #16716771
> llvm-objdump: warning: invalid instruction encoding
> 
> The binaries I try to read are c++ dynamic libraries for Android.
> 
> I have used the following parameters:
> 
> -llvm-objcdump mylib.so -d -arch=arm
> -llvm-objcdump mylib.so -d -arch=armv7
> -llvm-objcdump mylib.so -d -arch=thumb
> 
> or with the following triples:
> 
> armv7-none-linux-android
> thumbv7-none-linux-android
> 
> Does anyone know why I have this error? Am I missing some input parameters?
> 
> This is strange because it works great on iOS binaries (both thumb or arm).
> 
> Greetings,
> 
> Johan
> _______________________________________________
> LLVM Developers mailing list
> llvm-dev at lists.llvm.org <mailto:llvm-dev at lists.llvm.org>
> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
<http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev>
> 
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