Date: Sat, 14 Jun 2008 02:02:07 -0700 From: "Peter Wemm" <peter@wemm.org> To: "Julian Elischer" <julian@elischer.org> Cc: FreeBSD Current <current@freebsd.org> Subject: Re: mprof and new systems.. Message-ID: <e7db6d980806140202i28ef94abj28b7d849e7ff413@mail.gmail.com> In-Reply-To: <48537D07.8050305@elischer.org> References: <48537B5F.30207@elischer.org> <48537D07.8050305@elischer.org>
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On Sat, Jun 14, 2008 at 1:10 AM, Julian Elischer <julian@elischer.org> wrote:
> Julian Elischer wrote:
[..]
>> Anyone with ideas as to how to make the port act reliably?
Check out __builtin_return_address() and __builtin_frame_pointer().
Or look at src/sys/i386/i386/stack_machdep.c (it is present on all platforms).
info gcc -> 'C Extensions' -> 'Return Address'
-- Built-in Function: void * __builtin_return_address (unsigned int
LEVEL)
This function returns the return address of the current function,
or of one of its callers.
..
-- Built-in Function: void * __builtin_frame_address (unsigned int
LEVEL)
This function is similar to `__builtin_return_address', but it
returns the address of the function frame rather than the return
address of the function.
__builtin_frame_address() on i386 is basically:
register_t ebp;
__asm __volatile("movl %%ebp,%0" : "=r" (ebp));
or for amd64:
register_t rbp;
__asm __volatile("movq %%rbp,%0" : "=r" (rbp));
--
Peter Wemm - peter@wemm.org; peter@FreeBSD.org; peter@yahoo-inc.com
"All of this is for nothing if we don't go to the stars" - JMS/B5
"If Java had true garbage collection, most programs would delete
themselves upon execution." -- Robert Sewell
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