always_inline and LTO

always_inline and LTO

[Al K]

Hi,

I'm curious to know if the standard 'static inline' rules apply to
always_inline functions defined externally
but with LTO. For example,

    // foo.h
    extern __attribute__((__always_inline__)) void foo(void);

    // foo.c
    #include "foo.h"

    void foo(void)
    {
        ...
    }

    // bar.c
    #include "foo.h"

    __attribute__((__visibility__("default"))) void bar(void)
    {
        ...
        foo();
        ...
    }

Assuming both foo.c and bar.c are compiled with "-flto
-fvisibility=hidden -c" and then the resulting
objects are linked with "-flto":

1. Is it reasonable to expect that every invocation of foo() would be inlined?
2. Is it reasonable to expect that the definition for foo() would
never be emitted out-of-line (unless
    f.e. a pointer to foo was taken)?
3. Will warnings be emitted if foo() can't be inlined?

Thanks,
Aaloan