Re: [Xen-devel] [PATCH 2/2] tools: detect appropriate debug optimization level

[Ian Jackson <Ian.Jackson@xxxxxxxxxxxxx>]

Doug Goldstein writes ("[PATCH 2/2] tools: detect appropriate debug 
optimization level"):
> The build should not use -O0 as that results in miscompilations. There
> have been a few instances on the ML where users were told to switch
> from -O0 to -O1 or -O2 or to set debug=n and their issue went away. The
> preferred route should be to use -Og if its available, otherwise use
> -O1 which is the default. This change undoes the change from -O1 to -O0
> in 1166ecf781b1016eaa61f8d5ba4fb1fde9d599b6.

To summarise: I agree with using -Og if it is available.  But I
disagree with reverting 1166ecf7 in the case where it isn't; if -Og is
not available, we should stick with -O0.

I'm open to persuasion in the latter point but I would like specific
examples of problems (and then I would form an opinion about the
specific problems), not generalities.

Doug, would you like to, for now, propose a patch that uses -Og if it
is available, but otherwise falls back to -O0 ?  NB that if
convenient, this can be done simply by always specifying -O0 and
putting -Og after it if it is supported.

Thanks,
Ian.

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