Set macro NDEBUG for release builds

[betzw]

It seems as if the macro NDEBUG gets never set even if doing a release build.
Or is this intentionally left to be specified on the command line with -DNDEBUG?

[screamerbg]

@betzw Is this still relevant? I think this was fixed in the mbed OS build tools.

[betzw]

After merging the latest version of the master branch I still do not see an automatic definition of macro NDEBUG.
Furthermore, the usage of flag -o seems now not working anymore 👎

[bridadan]

@betzw The -o flag has been replaced with the more general --profile flag, you should be able to use that and it offers greater flexibility

[betzw]

Maybe you should reflect this in the documentation including the help message which gets printed by mbed compile -h.
What about macro NDEBUG? Is there a profile which defines it?

[bridadan]

Thanks @betzw, I submitted a PR here for just that: #365

I'm not as familiar with the NDEBUG option, so sorry I can't comment on it. Build profiles don't actually specify macros, just compiler flags. You should be able to set the NDEBUG macro through the config system.

[pan-]

@bridadan

Build profiles don't actually specify macros, just compiler flags.

So then it should be possible to add -D NDEBUG I guess.

[bridadan]

Yup, -D NDEBUG should do the trick. You can also add it to your mbed_app.json config file if you don't feel like typing it on the command line. More info on application config is available here: https://github.com/ARMmbed/mbed-os/blob/master/docs/config_system.md#configuration-data-in-applications

[pan-]

Sorry, I wasn't clear. I mean, -D NDEBUG is a compiler flag (for GCC at least, other compilers also support defines on the command line) so it should be possible to add it to a build profile instead of polluting the command line or mbed_app.json.

[bridadan]

@pan- Oh you're absolutely right, my bad! Yeah you technically can do that since its just a compiler flag 😄 Though I would imagine we wouldn't be adding many (if any) compiler flags directly to the default build profiles since we then can't configure them. However with custom build profiles, you're free to do as you wish. Just know that things may break. (not necessarily from NDEBUG, but just adding flags in general since we can't test every configuration of this)

[betzw]

As I can see you have defined a debug.json and a default.json build profile. Typically, macro NDEBUG should be defined for "release" builds (e.g. it removes the code for assertions), for which currently there is no ecplicit profile in mbed-os.

Btw, how do those profiles work? Do they all inherit from default.json and then add the flags specified in the current profile?
Where can I find more documentation regarding profiles?

[bridadan]

The documentation for build profiles are here: https://github.com/ARMmbed/mbed-os/blob/master/docs/Toolchain_Profiles.md

I'm actually not 100% sure about the inheritance of the profiles. @theotherjimmy could you clarify this and maybe add it to the documentation?

[screamerbg]

Ping @theotherjimmy

[betzw]

Ping @theotherjimmy