How to force string (rodata.str) alignment with ARM 6.6.3

Hi Bastian,

Do you just need to use __attribute__((aligned(4))) when you declare the string?

 https://developer.arm.com/docs/dui0774/j/compiler-specific-function-variable-and-type-attributes/__attribute__aligned-type-attribute

(better documented in later versions)

https://developer.arm.com/docs/101754/0614/armclang-reference/compiler-specific-function-variable-and-type-attributes/__attribute__aligned-variable-attribute

Regards

Ronan

But does this work with constant string like in the example? I tried, but it did not work in the first attempt:

create("name" __attribute__((aligned(4))) );

Edit:
I tried: __attribute__((align(4))) "default" and  "default" __attribute__((align(4)))

None works.

Hi Bastian

Declaring like this worked for me.

char __attribute__((aligned(4))) string1[] = "abcde";

Could you share a larger snippet of your code?

Yes this works for me as well. This is actually my workaround:

/* Workaround */
void func()
{
  char name[12]; /* automatic aligned to 4 bytes as it is on stack*/
  
  strcpy(name, "process");
  create(name);
}

void func2()
{
  create("process"); /* constant string might be placed on any boundary */
}

func2() would show the original code.

create() (assembly function) would read the name 32bit wise. This works fine on architecture > Armv6-M, but not for Armv6-M.

The workaround is ok and I can live with it, but it is a pity there is no way to force alignment.