Re: [RFA 1/2] mips: Switch inferior function calls to ON_STACK method.

["Maciej W. Rozycki" <macro at codesourcery dot com>]

Mark,

> >  Thanks for this work -- can you give me a reference to some background 
> > information as to why exactly we want to remove the AT_SYMBOL method?
> 
> The AT_SYMBOL method relies on a magic symbol being present in the
> binarie that's being debugged.  There is no guarantee that that magic
> symbol is actually present in your binary.

 And failing that the executable's entry point.  Actually I have yet to 
see a binary that has that magic __CALL_DUMMY_ADDRESS symbol, so the 
fallback must have worked pretty well.  Interestingly enough it was the 
MIPS target AT_SYMBOL was specifically added for:

http://sourceware.org/ml/gdb-patches/2003-08/msg00076.html

And that very patch regrettably removed the explanation of the actual 
reason of the whole arrangement -- the need to be able to debug a program 
in ROM that does not have an entry point (or I think, probably more 
accurately, rather has a read-only entry point such as the reset vector, 
so a breakpoint is not guaranteed to work there).

 Of course ON_STACK solves that in a more general manner, so that's the 
actual benefit from this change.  That removes any doubt I might have had.

 Thanks for your input, including your other comments.

  Maciej