[Aboriginal] undefined reference to `finite'

[Rob Landley]

On 04/05/2011 05:12 AM, David Seikel wrote:
> I'm very tired, and slightly ill, and I can't figure this out.
> 
> One of the packages from the UI library I want to use for this project
> uses a function called finite(double).  As far as I can tell, uClibc
> should supply that function, since we have DO_C99_MATH=y in its
> baseconfig. It's not being found though.
> 
> It's all buried in a forest of #ifdef's that my tired mind is in no
> condition to sort out.
> 
> I'm only two packages away for having all my needed libraries installed
> before I can start cutting code.  Time to sleep.

Hmmm...  Posibly a question for the uClibc mailing list?

You didn't say which target you were using, so I'll poke at x86_64:

$ cd build/cross-compiler-x86_64/lib
$ grep finite *
Binary file libm-0.9.31.so matches
Binary file libm.a matches
Binary file libm.so matches
Binary file libm.so.0 matches
$ ../bin/x86_64-readelf -a libm.so | grep finite
    40: 0000000000007ad0    18 FUNC    GLOBAL DEFAULT    6 __finitef
    58: 000000000000656c    23 FUNC    GLOBAL DEFAULT    6 __finite
    63: 0000000000000000     0 FILE    LOCAL  DEFAULT  ABS s_finite.c
   102: 0000000000000000     0 FILE    LOCAL  DEFAULT  ABS s_finitef.c
   171: 0000000000007ad0    18 FUNC    LOCAL  HIDDEN    6 __GI___finitef
   177: 000000000000656c    23 FUNC    LOCAL  HIDDEN    6 __GI___finite
   290: 0000000000007ad0    18 FUNC    GLOBAL DEFAULT    6 __finitef
   308: 000000000000656c    23 FUNC    GLOBAL DEFAULT    6 __finite

It looks like the problem is that uClibc is sticking two underscores on
the front of the "finite" symbol.  I'm not sure why.  It's not doing
that with other symbols, ala:

$ ../bin/x86_64-readelf -a libm.so | grep floor
    28: 0000000000006584   299 FUNC    GLOBAL DEFAULT    6 floor
   131: 0000000000007de8    19 FUNC    GLOBAL DEFAULT    6 floorf
    64: 0000000000000000     0 FILE    LOCAL  DEFAULT  ABS s_floor.c
   162: 0000000000006584   299 FUNC    LOCAL  HIDDEN    6 __GI_floor
   278: 0000000000006584   299 FUNC    GLOBAL DEFAULT    6 floor
   381: 0000000000007de8    19 FUNC    GLOBAL DEFAULT    6 floorf

My next step would be to dig down into the uClibc source code and build
system and try to figure out where that symbol comes from and maybe if
there's some sort of other config symbol to tell it not to do that.
(The build leaves that under build/packages/uClibc by the way, extracted
with all patches applied.  The gory details are explained at
http://landley.net/aboriginal/FAQ.html#debug_source although there's a
lot of reading to do to hack through it all.  It was more elaborate to
write, and if you have suggestions for simplifying it I'm all ears.  But
understand what it _does_ first, please...)

By the way, have you read this yet?

  http://www.muppetlabs.com/~breadbox/software/tiny/teensy.html

One of the best quick and dirty "get familiar with elf file format"
things I've seen...

Rob

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