OpenBSD-4.6/gnu/usr.bin/gas/README.pic

A few short notes on PIC support.

. References to the symbol "_GLOBAL_OFFSET_TABLE_" are special. These always
  PC relative to the start of the current instruction. Also, they occur
  in "complex" expressions in function prologs, eg.

	move	_GLOBAL_OFFSET_TABLE_ + (. - L1 ), %some_register

  The expression parser can't handle these generically, so the expression
  above is recognised as a special case.

. Some archs have special PIC assembler syntax to reference static and global
  data. This is handled in targ-cpu.c.

. Correct relocation_info must be output (eg. fields r_jmptable and r_baserel).

. Internal labels must be output in the symbol table if they are referred to
  by PIC instructions. The linker must allocate a GOT slot for them.
 
. The former meaning of the -k switch ("WORKING_DOT" stuff), has been nuked
  in favour of enabling PIC code recognition.


-pk