On Fri, Apr 13, 2012 at 12:46 PM, Dave Korn <dave.korn.cyg...@gmail.com> wrote: > On 13/04/2012 22:45, Oleg Smolsky wrote: >> On 2012-04-11 01:50, Vincent Lefevre wrote: >>> On 2012-04-09 13:03:38 -0500, Gabriel Dos Reis wrote: >>>> On Mon, Apr 9, 2012 at 12:44 PM, Robert Dewar<de...@adacore.com> wrote: >>>>> On 4/9/2012 1:36 PM, Jonathan Wakely wrote: >>>>> >>>>>> Maybe -Wstandard isn't the best name though, as "standard" usually >>>>>> means something quite specific for compilers, and the warning switch >>>>>> wouldn't have anything to do with standards conformance. >>>>> -Wdefault >>>>> >>>>> might be better >>>> except if people want warnings about "defaults" in C++11 (which can mean >>>> lot of things). >>> How about a warning level? >>> >>> -W0: no warnings (equivalent to -w) >>> -W1: default >>> -W2: equivalent to the current -Wall >>> -W3: equivalent to the current -Wall -Wextra >>> >> This is exactly what Microsoft C++ compiler does and what their Visual >> Studio IDE exposes in the UI. So, there is a reasonable precedent. > > Exactly. Would anyone really think it would be a good idea to just not have > the -O<number> levels and expect every end user to mix-and-match from a huge > set of somewhat unknown-and-unpredictable-just-from-the-names long and > confusingly named individual optimisation suboptions? I think -W levels is a > new feature that we can easily retrofit on top of the existing structure > without having to break or change anything that already works, and that would > be equally as user-friendly and pragmatic as having -O levels has already > shown itself to be.
First, I think the -Wn option is fantastic, and I look forward to seeing it. Second, some questions. With -O, it's often said that a given -On level does not correspond to an equivalent list of -f options. I believe even the manual states that for instance -O2 is a bunch of -f's plus some other stuff that you can't turn on without -O2. Would warnings options avoid this? IMO, that's a deficiency in -O, and meta options should be strictly meta. So I guess I'm really asking that the precedent be set that -Wn is always an amalgamation of existing -W options, and that we avoid the -On situation. Can the -Winf option really happen? It should be easy to make that turn on every -W option without having the manually list them and keep it up to date. Like, it should be easy, I would hope, to make that be automatic. Even if just used as a toy, I think this is a neat idea that would not require much work. Would a plugin be able to add in -W's to a given level? So like, I want to use MyPlug, and that comes with it -WMyWarn. I'd like my plugin to be able to say that -W2 turns on -WMyWarn.
