Re: PING^1 [PATCH] testsuite: 'b' instruction can't do long enough jumps

[Christophe Lyon <christophe.lyon@arm.com>]

Hi!


On 9/28/22 11:17, Torbjorn SVENSSON via Gcc-patches wrote:
> Hi,
> 
> Ping: https://gcc.gnu.org/pipermail/gcc-patches/2022-September/601829.html
> 
> Kind regards,
> Torbjörn
> 
> On 2022-09-19 18:30, Torbjörn SVENSSON wrote:
>> After moving the testglue in commit 9d503515cee, the jump to exit and
>> abort is too far for the 'b' instruction on Cortex-M0. As most of the
I am not sure I understand why that commit changed the distance between 
'exit' and the branch instruction?

>> C code would generate a 'bl' instruction instead of a 'b'
>> instruction, lets do the same for the inline assembler.
>>
>> The error seen without this patch:
>>
>> /tmp/cccCRiCl.o: in function `main':
>> stack-protector-1.c:(.text+0x4e): relocation truncated to fit: 
>> R_ARM_THM_JUMP11 against symbol `__wrap_exit' defined in .text section 
>> in gcc_tg.o
>> stack-protector-1.c:(.text+0x50): relocation truncated to fit: 
>> R_ARM_THM_JUMP11 against symbol `__wrap_abort' defined in .text 
>> section in gcc_tg.o
>> collect2: error: ld returned 1 exit status
>>
Anyway the change seems sensible to me, I suppose it's not worth adding 
support in the linker to insert long branch stubs for these relocations.

Christophe

>> gcc/testsuite/ChangeLog:
>>
>>          * gcc/testsuite/gcc.target/arm/stack-protector-1.c: Use 'bl'
>>     instead of 'b' instruction.
>>     * gcc/testsuite/gcc.target/arm/stack-protector-3.c: Likewise.
>>
>> Co-Authored-By: Yvan ROUX  <yvan.roux@foss.st.com>
>> Signed-off-by: Torbjörn SVENSSON  <torbjorn.svensson@foss.st.com>
>> ---
>>   gcc/testsuite/gcc.target/arm/stack-protector-1.c | 4 ++--
>>   gcc/testsuite/gcc.target/arm/stack-protector-3.c | 2 +-
>>   2 files changed, 3 insertions(+), 3 deletions(-)
>>
>> diff --git a/gcc/testsuite/gcc.target/arm/stack-protector-1.c 
>> b/gcc/testsuite/gcc.target/arm/stack-protector-1.c
>> index 8d28b0a847c..3f0ffc9c3f3 100644
>> --- a/gcc/testsuite/gcc.target/arm/stack-protector-1.c
>> +++ b/gcc/testsuite/gcc.target/arm/stack-protector-1.c
>> @@ -56,8 +56,8 @@ asm (
>>   "    ldr    r1, [sp, #4]\n"
>>       CHECK (r1)
>>   "    mov    r0, #0\n"
>> -"    b    exit\n"
>> +"    bl    exit\n"
>>   "1:\n"
>> -"    b    abort\n"
>> +"    bl    abort\n"
>>   "    .size    main, .-main"
>>   );
>> diff --git a/gcc/testsuite/gcc.target/arm/stack-protector-3.c 
>> b/gcc/testsuite/gcc.target/arm/stack-protector-3.c
>> index b8f77fa2309..2f710529b8f 100644
>> --- a/gcc/testsuite/gcc.target/arm/stack-protector-3.c
>> +++ b/gcc/testsuite/gcc.target/arm/stack-protector-3.c
>> @@ -26,7 +26,7 @@ asm (
>>   "    .type    __stack_chk_fail, %function\n"
>>   "__stack_chk_fail:\n"
>>   "    movs    r0, #0\n"
>> -"    b    exit\n"
>> +"    bl    exit\n"
>>   "    .size    __stack_chk_fail, .-__stack_chk_fail"
>>   );