Re: [ARM] Don't shorten long calls to different sections

[Richard Sandiford <richard at codesourcery dot com>]

Richard Earnshaw <rearnsha@arm.com> writes:
> On Thu, 2007-05-24 at 21:25 +0100, Richard Sandiford wrote:
>> If function A calls long_call function B, the ARM port tries to
>> convert the call into a short call if it thinks B is in range.
>> There is some code to prevent this optimisation when A and B
>> are in different sections, but it isn't complete:
>> 
>>   - Non-sibling and sibling calls to B are shortened when B is weak.
>>     (The strong definition might not be in range.)
>> 
>
> ??? I was under the impression that the opposite was true for
> non-sibling calls: namely that calls to a weak B were never shortened,
> even if the user hadn't requested long calls.  Eg:
>
> int y;
> int __attribute__((weak)) x () { return y; }
> int f() { return x(); }
>
> generates an indirect call when compiled with -O.

Sorry, yes, I misread the testcase FAILs from the pre-patch compiler.
It was only sibling calls to long_calls that were affected.  I.e.

int y;
int __attribute__((weak, long_call)) x () { return y; }
int f() { return x(); }

would use a short call at -O2.

Do you want the retain the behaviour that all calls to weak functions
are assumed long?  Or is it OK to treat them simply as calls to
externally-defined functions, as the patch does?  (I realise you
said OK, just thought I'd better clarify.)

Richard