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What does "Error: L6248E: cannot have address type relocation" mean?

Applies to: ARM Developer Suite (ADS), RealView Developer Kit (RVDK) for OKI, RealView Developer Kit for XScale (RVXDK), RealView Development Suite (RVDS)

Answer

This linker error can occur when trying to build "Position Independent" code. Consider a small example like:

#include <stdio.h>
char *str = "test";
int main(void)
{
    printf ("%s",str);
}

when compiled and linked with:

armcc -c -apcs /ropi pi.c
armlink -ropi pi.o

the linker will report a message of the form:

Error: L6248E: pi.o(.data) in ABSOLUTE region 'ER_RW' cannot have address/offset type
relocation to .constdata in PI region 'ER_RO'.

For the code above, the compiler generates a global pointer "str" to the char string "test". The global pointer "str" will need to be initialized to the address of the char string "test" in the .constdata section. However, absolute addresses cannot be used in a PI system, so the link step fails, because of the ABS32 relocations to (position independent) .constdata.

To resolve this, you must re-write the code to avoid the explicit pointer. Two possible ways are shown below:

1) Use a global array instead of a global pointer:

#include <stdio.h>
const char str[] = "test";
int main(void)
{
    printf ("%s",str);
}

2) Use a local pointer instead of a global pointer:

#include <stdio.h>
int main(void)
{
    char *str = "test";
    printf ("%s",str);
}

Please note that if you are using a list with multiple elements, such as:

char * list[] = {"zero", "one", "two"};

You will get a separate link error for each element in the array. In this case, the recommended solution is:

char list[3][5] = {"zero", "one", "two"};

with the print instruction being (for example):

printf("%s", list[1]);

Note that you will need to declare a two dimensional array for the list, with the first dimension as the number of elements in the array, and the second dimension as the maximum size for an element in the array.

Article last edited on: 2009-04-16 15:59:06

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