On 06/02/20 15:37, Pankaj Bansal (OSS) wrote: > > >> -----Original Message----- >> From: Laszlo Ersek <ler...@redhat.com> >> Sent: Tuesday, June 2, 2020 7:00 PM >> To: Leif Lindholm <l...@nuviainc.com>; devel@edk2.groups.io; >> michael.d.kin...@intel.com >> Cc: Andrew Fish <af...@apple.com>; Pankaj Bansal (OSS) >> <pankaj.ban...@oss.nxp.com> >> Subject: Re: [edk2-devel] [PATCH edk2-InfSpecification] Drop statement on >> package ordering >> >> On 06/01/20 00:43, Leif Lindholm wrote: >>> Hi Mike, >>> >>> Ok, I'm happy to hear that. >>> >>> I agree that the overriding behaviour is useful, and it would be good >>> to document it. The problem is that the current wording does not say >>> that (in a way that is useful to anyone who does not already know what >>> it means). And the MdePkg/MdeModulePkg example sounds positively >>> horrific when interpreted in this light. >>> >>> Clearly, my proposed modification is not the right thing to do here. >>> >>> The problem with the document implying that the order should reflect >>> some sort of hierarchy *apart from when explicitly overriding* is that >>> this is asking a human to do the thing that humans are bad at and >>> computers are good at. It can't scale where humans are reviewing ports >>> that they understand less well than the people contributing them. >>> >>> I think we should find a wording that explains the behaviour instead >>> of explaining some potential derivative of the behaviour, as well as >>> providing a realistic example instead of the MdePkg/MdeModulePkg >>> statament. >>> >>> My suggestion is to keep it simple: say something like "where there is >>> a need to override an include file provided by one package with one >>> provided by another package, know that the compiler invocation will >>> list the include directories in the same order as the .dec files are >>> listed in the .inf". >> >> (since I've been copied) >> >> I have not been aware of the header name collision scenario (nor that >> the [Packages] ordering was supposed to work around such issues). >> >> I work strictly with edk2 proper, where a name collision like this can >> be detected, and so should be prevented. (Insert yet another argument >> why keeping platform code outside of edk2 is a bad idea.) In particular, >> a collision between MdePkg and MdeModulePkg would be super bad. >> >> Which now seems to turn out consistent with my general review point that >> the [Packages] section, like (almost) all other INF file sections, >> should be sorted lexicographically. >> >> How about replacing >> >> """ >> Packages must be listed in the order that may be required for specifying >> include path statements for a compiler. For example, the MdePkg/MdePkg.dec_ >> file must be listed before the `MdeModulePkg/MdeModulePkg.dec` file. >> """ >> >> with >> >> """ >> The order in which packages are listed may be relevant. Said order >> specifies in what order include path statements are generated for a >> compiler. Normally, header file name collisions are not expected between >> packages -- they are forbidden in edk2 proper --, but with a module INF >> consuming both edk2-native and out-of-edk2 packages, header file names >> may collide. For setting specific include path priorities, the packages >> may be listed in matching order in the INF file. Listing a package >> earlier will cause a compiler to consider include paths from that >> package earlier. >> """ > > Nicely summed up! it is much clearer now for anyone like me who wants to port > edk2 for his platform. > one more suggestion. should this be mentioned along with above explaination: > "whenever possible use lexicographically ascending order"
I'd love that, but it's really just a policy question that I prefer. If we tried to elevate my preference to official edk2 spec level, it could run into opposition (like any other proposal -- so that would be just fine, per se!). I just wouldn't like to delay the more important clarification with a discussion around my preference. So minimally, that would take a two-part patch series, and even so the second patch would likely have to be marked RFC. I think we can simply postpone the official speccing of the lexicographical sorting idea (indefinitely, even). Thanks Laszlo -=-=-=-=-=-=-=-=-=-=-=- Groups.io Links: You receive all messages sent to this group. View/Reply Online (#60598): https://edk2.groups.io/g/devel/message/60598 Mute This Topic: https://groups.io/mt/74544111/21656 Group Owner: devel+ow...@edk2.groups.io Unsubscribe: https://edk2.groups.io/g/devel/unsub [arch...@mail-archive.com] -=-=-=-=-=-=-=-=-=-=-=-
