On Oct 3, 2006, at 5:43 PM, Brendon Costa wrote:
I think I could insert my data into the .s file into a particular
section. I am not sure if I should create my own named section
I'd recommend .comment probably. If you want to productize it, add
your own, and put it into your linker script.
If I place it into the .data section then would it then be possible to
have conflicts with code symbols?
Only if you add a symbol that can have conflicts with code symbols,
see the language spec for which symbols you can and cannot use. __foo
$bar is safe for example to use. printf generally isn't.
I am also not yet sure how I would extract this data from the
objects (Using libbfd somehow I will have to look further into it).
man objcopy, man objdump
objdump --section=.comment --full-contents a.out
for example.
What would be the best directive to use to insert binary data into the
section?
If you have a word
.word 0
see the assembler manual for other possibilities.
.string "Hello world\n\0"
might also work, if you have strings. Also, you can ask the compiler
how to output data by using the -S flag.
Also does using ar/ld on resulting .o files filter out any sections
they don't know about?
as no. ld -r, no. Final link, probably. --print-map for example
might tell you some of the information you might need. Look at the
default linker script. I can use use emacs /usr/bin/ld to view mine
for example. :-)
You can google("ld options dump liinker script") and find out that ld
--verbose is an easier way to figure out the default linker script for
GNU ld.
Or do they always just include sections into the resulting archive/
executable even if the sections are non-standard containing meta-
data that they don't understand?
.comment is standard on my platform.
