The eh_frame data is used to unwind the stack when an exception is
thrown. It records things like where to find the return address and
which registers are stored where.
Ah, so eh_frame is just a table of meta-data describing the code in
the data section, right? (no executable code in eh_frame itself?)
And I'm guessing it needs relocation entries in order to reference
the sizes/positions of items linked in other sections?
bfd/elf-eh-frame.c
This file is in binutils... looking through it shows how to read/
write the data, which is half the battle, but the data is apparently
being generated elsewhere.
Of particular interest to me is a change which occurred from gcc 3.3
branch to 3.4 and beyond: in 3.3 the eh_frame section used to contain
only R_MIPS_PC32 entries, which didn't need to be listed in the
relocation table I generate. In 3.4 R_MIPS_32 entries are used
instead, which I do need to handle. (So another angle of attack is
to figure out how to switch back to R_MIPS_PC32 relocation entries so
I don't have to muck around in eh_frame to begin with...)
Do you know where I can look in gcc to find the eh_frame generation?
(or better yet, some insight into what I would need to change to
either make eh_frame consistent or make it use R_MIPS_PC32 type
relocation entries?)
thanks,
-ethan
