[avr-gcc-list] Broken R_AVR_16 relocation? Or is my compiler wrong?

[Dylan McKay]

Hello there,

I am generating AVR executables with my own compiler, but linking them with AVR-GCC.

Here is an example of a C file, which avr-as compiles fine. I made sure to first use my compiler to generate assembly from this file, and then assemble this using my compiler and gcc so that they are both using the same assembly source file.

void foo();
int bar = 2;
int abc = 2;

int jmp __attribute__((section(".vectors"))) = 0x940C;
void (*ptr)()  __attribute__((section(".vectors"))) = (&foo);

void milan() { }
void foo(){}
void inter() { }

int qwerty = 2;

The .vectors section is generated fine. The correct jmp instruction is placed. Both compilers generate R_AVR_16 relocations for this.

GCC however generates this (avr-objdump output):

RELOCATION RECORDS FOR [.vectors]:
OFFSET   TYPE              VALUE 
00000004 R_AVR_16          .text+0x00000004

Note that .text+0x00000004 does point to foo in the object file.

Whereas my compiler generates this:

RELOCATION RECORDS FOR [.vectors]:
OFFSET   TYPE              VALUE 
00000002 R_AVR_16          foo

The problem is that GCC’s hardcoded section+offset works, but my symbol does not. avr-ld correctly relocates GCC code to foo in the executable, but relocates my code to _etext+0x2.

Am I doing something wrong, or is not just not properly supported?

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