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Bug#862514: marked as done (Gcc creates illegal instructions when combining C + ASM on arm on sid)

Your message dated Wed, 21 Jun 2017 15:58:03 +0200
with message-id <f249e8ab-0cb7-61df-1fd9-9abc5dcc4515@debian.org>
and subject line Re: Bug#862514: Gcc creates illegal instructions when combining C + ASM on arm on sid
has caused the Debian Bug report #862514,
regarding Gcc creates illegal instructions when combining C + ASM on arm on sid
to be marked as done.

This means that you claim that the problem has been dealt with.
If this is not the case it is now your responsibility to reopen the
Bug report if necessary, and/or fix the problem forthwith.

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-- 
862514: http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=862514
Debian Bug Tracking System
Contact owner@bugs.debian.org with problems
--- Begin Message --- 
Package: gcc
Version: 6.3.0-4

Gcc creates binaries that fail with "invalid instruction". To
reproduce create the following main.c:

 int get_retval(void);

int main(int argc, char **argv) {
  return get_retval();
}

and the following retval-arm.S

.text
.globl get_retval

get_retval:
        mov     r0, #0
        bx      lr

Compile like this:

gcc -o prog main.c retval-arm.S

The result crashes. However if you add -march=armv7 the executable
works (-march=native crashes also).

This only happens on GCC using the version in Sid. It works when using
any version of Clang and also when using GCC in Jessie.

Originally reported here: https://github.com/mesonbuild/meson/issues/1776

--- End Message ---
--- Begin Message --- 
not a compiler bug. the get_retval symbol is untyped, so it doesn't get proper
interworking treatment. add a .type get_retval, %function directive

On 21.06.2017 10:09, Uwe Kleine-König wrote:
> Hello,
> 
> On Wed, Jun 21, 2017 at 09:09:41AM +0200, Uwe Kleine-König wrote:
>> On Sun, May 14, 2017 at 12:09:42AM +0300, Jussi Pakkanen wrote:
>>> Package: gcc
>>> Version: 6.3.0-4
>>>
>>> Gcc creates binaries that fail with "invalid instruction". To
>>> reproduce create the following main.c:
>>>
>>>  int get_retval(void);
>>>
>>> int main(int argc, char **argv) {
>>>   return get_retval();
>>> }
>>>
>>> and the following retval-arm.S
>>>
>>> .text
>>> .globl get_retval
>>>
>>> get_retval:
>>>         mov     r0, #0
>>>         bx      lr
>>>
>>> Compile like this:
>>>
>>> gcc -o prog main.c retval-arm.S
>>
>> I cannot reproduce this on a Marvell Armada XP Development Board
>> (DB-MV784MP-GP) (i.e. abel.debian.org) using gcc 4:6.3.0-4. Can you
>> please provide the output of
>>
>> 	objdump -d 
>>
>> ?
> 
> I could reproduce it on armhf now. (I picked armel before because the
> original report talks about rpi1.) The (relevant part of the) output
> looks as follows:
> 
>   000005a4 <main>:
>    5a4:   b580            push    {r7, lr}
>    5a6:   b082            sub     sp, #8
>    5a8:   af00            add     r7, sp, #0
>    5aa:   6078            str     r0, [r7, #4]
>    5ac:   6039            str     r1, [r7, #0]
>    5ae:   f000 f805       bl      5bc <get_retval> 
>    5b2:   4603            mov     r3, r0
>    5b4:   4618            mov     r0, r3
>    5b6:   3708            adds    r7, #8
>    5b8:   46bd            mov     sp, r7
>    5ba:   bd80            pop     {r7, pc}
>   
>   000005bc <get_retval>:
>    5bc:   e3a00000        mov     r0, #0
>    5c0:   e12fff1e        bx      lr
> 
> The problem is that main() uses Thumb while get_retval() uses ARM ISA
> and main does "bl" to get_retval() which doesn't do the necessary
> interwork.
> 
> Given that the used ISA is contained in the compiler artifact the linker
> should be able to at least error out in this case.
> 
> Best regards
> Uwe
>

--- End Message ---
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