Surprising result with ld -r

[Douglas B Rupp <rupp at adacore dot com>]

Given the attched files main.c, foo0.c, foo1.c
This is on x86_64-linux.

$ gcc -c foo0.c foo1.c main.c
$ gcc -o main1.pm foo0.o main.o
./main1.pm
foo0

However
$ gcc -o main1.pm foo0.o main.o -r -nostdlib
$ gcc -o main2.sm foo1.o main1.pm -Wl,-zmuldefs
./main2.sm
foo1

What is the rationale for -r not resolving "foo" in
$ gcc -o main1.pm foo0.o main.o -r -nostdlib
?

One would think that ld -r would resolve the global symbols it can 
resolve at each step, rather than waiting for the final link to resolve 
globals that are defined early.

--Douglas Rupp
AdaCore

#include <stdio.h>

void
foo ()
{
  printf ("foo0 called\n");
}

#include <stdio.h>
void
foo ()
{
  printf ("foo1 called\n");
}

extern void foo ();

void
main ()
{
   foo ();
}