Re: various Alpha patches

[Guy Harris <guy at netapp dot com>]

Sorry, I'm stupid.

Eirik's patch is the one in message

	http://sources.redhat.com/ml/gdb-patches/2000-07/msg00166.html

with the subject line "[PATCH]: alpha_frame_saved_pc()".

The two patches in

	http://sources.redhat.com/ml/gdb-patches/2000-07/msg00167.html

and

	http://sources.redhat.com/ml/gdb-patches/2000-07/msg00168.html

with subject lines "[PATCH]: (alpha) heuristic_proc_start()" and
"[PATCH]: (alpha) heuristic_proc_start", respectively, are from Kevin
Nomura - it appears to be a fix for NetApp bug 26292 (our bug system
tracks bugs on tools, as well as on the software on our appliances),
caused by some code generated on the fly building stack frames that GDB
can't follow; the comment for the fix was

	I'm changing alpha-tdep.c in gdb to use "lda sp,x(sp)" as the
	sentinel which identifies the start of a procedure in heuristic
	mode.  Heuristic mode is entered when the procedure lacks a PDR. 
	This occurs if symbols are stripped, but if symbols are not
	stripped it is fairly rare; even assembly procedures have PDRs
	(provided they were bracketed with .ent/.end).  [On-the-fly]
	generated code is the issue here and of course such procedures
	do not have PDRs.

	I also changed "heuristic-fence-post" to work as documented.  A
	value of 0, which is the default, was supposed to mean "search
	forever".  Instead a value of 0 meant "don't do any search"!. 
	This meant that "set heuristic-fence-post 100000" or some such
	was needed to backtrace through routines without PDRs.  Seeing
	how this flag is obscure and alpha-specific, I think the default
	should be "on" rather than "off".  The possible drawback is that
	when debugging over a serial line, if for some reason a "lda
	sp,x(sp)" was not present, gdb might go roaming through all of
	memory and effectively hang.  If this is a possibility then we
	should perhaps do something special in serial line debugging
	mode, or just make it default to off and require people to
	explicitly set their favorite value of heuristic-fence-post.

The change to "heuristic-fence-post" is the change in the first of those
messages; the other change is the change in the second of those
messages.