Rockbox

What problem does gcc 4.1.1 have with declaring start_thread as static? Do you know if this is a deliberate change in behaviour by gcc or a bug?

Error message is:
/cygdrive/c/rockbox/build-device/librockbox.a(thread.o): In function `create_thread':
thread.c:(.text+0x95c): undefined reference to `start_thread'

I guess this may be caused by call from inline assembler in function 'load_context'?
static inline void load_context(const void* addr)
{

  asm volatile(
      "ldmia  %0, { r4-r11, sp, lr } \\n" /* load regs r4 to r14 from context */
      "ldr    r0, [%0, #40]          \\n" /* load start pointer */
      "cmp    r0, #0                 \\n" /* check for NULL */
      "movne  r1, %0                 \\n" /* if not already running, jump to start */
      "ldrne  pc, =start_thread      \\n" 
      : : "r" (addr) : "r0", "r1"
  );

}

Probably discards the "unreferenced" (by C code) static function as an "optimization" then tries to link it. Sounds buggy to me and obviously doesn't trip up arm-elf-gcc 4.0.3. :

Not sure if it is a bug; similar things can be seen in other places with newer versions of GCC. A better fix would be to add "attribute 1)" to start_thread. (While at it, one could also add "attribute 2)" to stuff that shouldn't be inlined.)

Here is patch with attribute 1).

   thread.diff (0.6 KiB)