foo ? foo() : puts( "foo == null, skipped." );

if foo is hidden, compiler assumes it will be defined in the same
component. On
x86-64, compiler may generate the following PIC code

        leaq    foo(%rip), %rax
        testq   %rax, %rax

PC relative address is used here. It will work correctly if foo is
defined in
the same component. If foo is weak, undefined and hidden. foo will be
zero. For normal executable, since the load address is fixed, llinker
can
turn

leaq    foo(%rip), %rax

into

leaq    -PC(%rip), %rax

rax will be 0. But for shared library, linker doesn't know the load
address.
To load 0 into %rax, linker will generate relocation in .text section
and
dynamic linker has to modify LEA at run-time to load 0 into rax.

Generate a DSO with DT_TEXTREL isn't very desirable. We want
to avoid it if possible. It is odd to tell compiler that you can't
always
assume a hidden symbol will be defined in the same component
when you access it.

H.J.

H.J.