Anticipating a Reply wrote:
> Thank you for the information given by
> you . It would be more helpful if you
> could let me know if there is some document
> which helps me interpret & understand the
> " spec " file and tells how it is used
> by gcc .
GNU toolchain stuff is unfortunately oft rather under- and/or obscurely
documented. In this case, the documentation lives in the GCC source. In
my gcc-3.2 tree, this "spec language" is described/defined in a large
comment in gcc/gcc.c.
Fortunately it's not a hard language. Let's take the *link spec
including that -rdynamic as an example:
===
*link:
-m elf_i386 %{shared:-shared} %{!shared: %{!ibcs: %{!static:
%{rdynamic:-export-dynamic} %{!dynamic-linker:-dynamic-linker
/lib/ld-linux.so.2}} %{static:-static}}}
===
This spec only uses the "%{S:X}" and "%{!S:X}" constructs. Translating
it into 'conventional pseudo-language' would give something like:
===
link = "-m elf_i386"
IF option("-shared") THEN
link += " -shared"
ENDIF
IF NOT option("-shared") THEN
IF NOT option("-ibcs") THEN
IF NOT option("-static") THEN
IF option("-rdynamic") THEN
link += " -export-dynamic"
ENDIF
IF NOT option("-dynamic-linker") THEN
link += " -dynamic-linker /lib/ld-linux.so.2"
ENDIF
ENDIF
IF option("-static") THEN
link += " -static"
ENDIF
ENDIF
ENDIF
===
As to how this *link spec is then used; look at the *link_command spec
in the gcc specfile. Specs can be substituted into one another using
the "%(...)" language-construct, and you will see the *link_command
spec incorporating for example the *linker spec by specifying
"%(linker)". The *link spec is special in that the language knows about
it internally: it's pulled in simply by "%l".
GCC then uses the *link_command spec directly as the command to run the
linker. See gcc-3.2/gcc/gcc.c:main(), near the end:
value = do_spec (link_command_spec);
Hope this helps.
Rene.
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