"Manuel López-Ibáñez" <[EMAIL PROTECTED]> writes: > On 30 May 2007 16:12:12 -0700, Ian Lance Taylor <[EMAIL PROTECTED]> wrote: >> Joe Buck <[EMAIL PROTECTED]> writes: >> >> > How about: have -Wall still set warn_strict_overflow >> > to 1, but to have -Wall -Wstrict-overflow *or* -Wstrict-overflow -Wall >> > *or* just -Wstrict-overflow set it to 2? The only change would be >> > to prevent -Wall from *decreasing* the value. >> >> Sure, makes sense. >> >> But, consider: > [snip] >> If we want to fix this issue, it seems to me we should fix it >> everywhere. > > I was going to submit a formal proposal about options handling (with > patches). Since this was raised before I had time to think it through > properly, it may have some flaws. > > Two kinds of options: group options (-Wall, -Wextra, -O1, -O2) and > simple options (-fpeephole, -Waddress, -Wstrict-overflow). > > * Group options can only affect default values of simple options. So a > group option will not change the settings of a explicit simple option > no matter their order in the command-line. So, "-Wno-address -Wall" == > "-Wall -Wno-address" > > * Options are evaluated according to their order in the command-line. > So, "-Wno-address -Waddress" will turn on -Waddress, while "-Waddress > -Wno-address" will turn it off. > > Both rules combined mean that you can do: "-Wall -Wno-all" disabling > "-Wall" warnings. However, if you do "-Waddress -Wall -Wno-all", you > still get -Waddress. You will need an explicit -Wno-address to disable > it. > > I think this corresponds to the principle of least surprise. Bad idea?
I like the idea. I'd also suggest that group options won't do anything else but affecting [default values of] simple options. It means that one will be able to substitute a set of simple options for a "group option" without change in behavior (for example, this is not currently the case for -O,-O1,-O2 options). -- Sergei.
