.eh_frame section on alpha
Ian Lance Taylor
ian@airs.com
Fri Dec 24 15:00:00 GMT 2004
Simon Burge <simonb@wasabisystems.com> writes:
> http://sources.redhat.com/ml/binutils/2003-05/msg00863.html added the
> generation of a .eh_frame section to all objects that otherwise didn't
> have them.
>
> On NetBSD, we have some tight code size constraints for our first stage
> boot loader - it needs to fit in 7.5k of space at the start of the disk.
> With binutils 2.14, our boot loader was 6880 bytes. With binutils 2.15,
> the boot loader is 7848. The only difference in size between the two is
> the .eh_frame section:
>
> 3 .eh_frame 000003c4 0000000020001990 0000000020001990 00001a40 2**3
> CONTENTS, ALLOC, LOAD, READONLY, DATA
>
> What exactly is this section used for? A bit of googling seems to
> indicate it's for exception handling, which isn't a C issue.
>
> More importantly, how can I disable the generation of this section? It
> seems that only alpha generates an .eh_frame section unconditionally.
Hi Simon. I haven't tested it, but there should be two ways to
disable to automatic creation of the .eh_frame section: 1) do not emit
the directives which create one--.ent, .end, .frame, etc.; 2) create
your own .eh_frame section and put nothing in it--for example, the
assembler doesn't generate its own unwind information for compiled
code, because the compiler creates a .eh_frame section anyhow.
However, I also think it would be a good idea to have an assembler
option to not create the unwind information.
Ian
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