Re: Handling of -fpic in ASM_OUTPUT_MI_THUNK in sparc

[Jason Merrill <jason at cygnus dot com>]

>>>>> Teemu Torma <tot@trema.com> writes:

> It seems that ASM_OUTPUT_MI_THUNK in sparc emits normal funcion call
> sequence when the file compiled is compiled with -fpic.  This sounds
> very slow, since the call goes thru the dynamic table and can lead to
> an additional register window trap.

It uses a normal function call because that's the only way to get the
appropriate relocs for PIC code.  There is no jmp that uses the procedure
linkage table.

> Is there any reason why not to emit the thunk to a writable segment?
> In that case -fpic condition could be taken away.

I suppose, but I can't imagine that a function call is as slow as all that.

> Besides, the current test does not help if the main program compiled
> without -fpic emits thunks that call methods in a shared library.

Huh?  How is this different from any other function that calls functions in
a shared library?

Jason