On 12/02/16 09:58, Umesh Kalappa wrote:
Hi Kyrill ,
Thank you for the info ,before i file a bug ,need to confirm its a bug or not .
I'm not familiar with linker scripts and the details of -fpie,
so unfortunately I can't judge.
Do file a bug report.
If it is not a bug, it will be closed as such by someone who does
the analysis.
Kyrill
Thank you
~Umesh
On Fri, Feb 12, 2016 at 3:00 PM, Kyrill Tkachov
<kyrylo.tkac...@foss.arm.com> wrote:
Hi,
On 12/02/16 09:19, Umesh Kalappa wrote:
Hi Guys ,
we do have a issue with below code ,When we enabled the pie (-fpie/pie)
option
i.e
main.c
extern int *my_ptr ;
int main()
{
return *my_ptr;
}
foo.s
.syntax unified
.cpu cortex-m0
.fpu softvfp
.thumb
.global my_ptr
.global my_var
.data
.align 2
.type my_ptr, %object
.size my_ptr, 4
my_ptr:
.word my_var //where my_var is the linker variable
custom.ld (linker script)
/* Set stack top to end of RAM, and stack limit move down by
190 * size of stack_dummy section */
191 my_var = 20;
192 __StackTop = ORIGIN(RAM) + LENGTH(RAM);
193 __StackLimit = __StackTop - SIZEOF(.stack_dummy);
194 PROVIDE(__stack = __StackTop);
command used
3 arm-none-eabi-gcc -c -fPIC main.c -mthumb -mcpu=cortex-m0
4
5 arm-none-eabi-gcc -c -fPIC foo.S -mthumb -mcpu=cortex-m0
6 arm-none-eabi-gcc -c -fPIC
/home/egoumal/Downloads/gcc-arm-none-eabi-5_2-2015q4/share/gcc-arm-none-eabi/samples/startup/startu
p_ARMCM0.S -mthumb -mcpu=cortex-m0 -D__STARTUP_CLEAR_BSS
-D__START=main
7
8 arm-none-eabi-ld -pie main.o foo.o startup_ARMCM0.o -L.
-L/home/egoumal/Downloads/gcc-arm-none-eabi-5_2-2015q4/share/gcc-ar
m-none-eabi/samples/ldscripts -T nokeep.ld -Map=test.map -o test
we expect my_ptr value to be 20 ,but we do see the value 0 and without
pie option ,the my_ptr has the value 20 .
do we missing something here or value 0 expected (which is incorrect)
note that gcc-bugs is the list where the automatic bug tracker sends all the
emails
logging almost all activity, so your email would be lost there...
Please file a bug report in bugzilla according to https://gcc.gnu.org/bugs/
Thanks,
Kyrill
Thank you and appreciate any lights on this
~Umesh
