Ian Lance Taylor wrote:
Michael Eager <eager@xxxxxxxxxxxx> writes:
I want a multilib configurations to specify two options,
not just a single option. I don't see anything in the
docs which describes how to do this or any target which
does this.
Is there a way to specify that the 'foo' multilib
config should be built with -mfoo and -mbar?
You can probably do this but it's not clear what you want. Multilibs
go two ways: they tell the build process which libraries to build at
build time, and they tell the compiler driver which libraries to link
against at link time. What should happen if somebody links using just
-mfoo or just -mbar?
-mbar is an optimization which is only valid if -mfoo is also specified.
Linking a non- -mbar lib with -mfoo works OK, -mbar with non- -mfoo fails.
During compile, if only -mfoo is specified, everything works OK.
With only -mbar, a warning message is generated which says that
it's only valid with -mfoo, and the option is suppressed. So
multilib is actually building a library which claims to be -mbar
but isn't.
We've been building libraries outside of gcc so that both -mfoo and
-mbar are specified. We overwrite the library built by gcc/multilib
with the correctly built library.
There seems to be another consequence of the warning message.
It looks like libstdc++ is being incorrectly configured because
the warning is interpreted as a failure while testing for the
existence of an include file. I don't know why this only happens
building libstdc++.
--
Michael Eager eager@xxxxxxxxxxxx
1960 Park Blvd., Palo Alto, CA 94306 650-325-8077
