objcopy symbol name for binary input

[Alon Bar-Lev]

Hi,

I am sure this comes up now and then.

When copying binary data to ELF the symbol name is created using the full
path of the input file. Using the full path is problematic when the build
is using a temporary path or the build is using full path vs relative etc...

For example:

arm-none-eabi-objcopy \
    --input-target binary \
    --output-target elf32-littlearm \
    --binary-architecture arm \
    /tmp/a.txt /tmp/a.o

Creates the following symbols:

_binary__tmp_a_txt_start
_binary__tmp_a_txt_end
_binary__tmp_a_txt_size

The symbols are not fixed, since these depend on the location of the files
or the current directory.

Yes, I can change directory to $(dirname) and use relative name, but why do
we assume that the section name is the file name? Yes, I can copy the file
to the requested section name then import, or change directory and
use --redefine-sym to rename the known name to what application expects.

The best solution I've seen so far is to use /dev/stdin, for example:

arm-none-eabi-objcopy \
    --input-target binary \
    --output-target elf32-littlearm \
    --binary-architecture arm \
    --redefine-sym _binary__dev_stdin_start=_mydata_start \
    --redefine-sym _binary__dev_stdin_end=_mydata_end \
    --redefine-sym _binary__dev_stdin_size=_mydata_size \
    /dev/stdin /tmp/a.o < /tmp/a.txt

This provides known symbols based on the static /dev/stdin and renames the
symbols to what application expects regardless of what the filename is,
where it is stored, if used relatively or absolute and what is the current
directory.

However, using /dev/stdin is still a hack.

Will you consider accepting a patch to add a command-line argument to set
the binary symbol similar to --prefix-symbols to add the symbol name or
allow ignoring the directory part.

Thanks,
Alon
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