Does one still need to use -fPIC when compiling with GCC?

Question

On gcc target machines, when one wanted to compile a shared library, one would need to specify -fpic or -fPIC to get things to work correcly. This is because by default absolute

Answer 1

You still need to compile with -fPIC. The problem isn't solvable with pc-relative addressing. The problem is how you resolve external symbols. In a dynamically linked program the resolution follows different rules and especially with adress space randomization it can't be resolved during link time.

And clang does have the -fPIC flag just like gcc.

$ cat > foo.c
void foo(void);
void bar(void) { foo(); }
$ gcc -S foo.c && grep call.*foo foo.s
    call    foo
$ gcc -fPIC -S foo.c && grep call.*foo foo.s
    call    foo@PLT
$ clang -S foo.c && grep call.*foo foo.s
    callq   foo
$ clang -fPIC -S foo.c && grep call.*foo foo.s
    callq   foo@PLT
$