On Thu, Jan 4, 2018 at 12:14 AM, foobar <foobar@xxxxxxxxxx> wrote: > #pragma directives other than #pragma once are not really meant for the preprocessor to consume. I am not sure I understand this. #pragma is not part of the normal C language grammar. It should be consumed at the preprocessor stage, it has some side effect for the compiler. > > in preprocessor_only mode, apart from pragma once, they should all be printed to stdout (unless they are under #ifdef that's not taken). I wonder what does the C spec say about this. > i've produced a patch that does that, however i'm not really happy about it, since i'm unclear about how to deal > with the pragma in non-preprocessor mode. > > i suppose the token-stream of the pragma-directive should be converted into some kind of special symbol, which can then be either consumed or ignored when doing the usual iteration over the symbol list. > but i didn't find an obvious symbol type to assign... If it is preprocessor symbol. It does not need to have C type. It can have the name space set to preprocessor. In theory you can also have a symbol_list keep track of all the pragma you see in the source file. Not sure that will serve you any purpose. > (my plan is to create a build tool based on sparse that gets directives as a special pragma). > > thanks! > > testcode: > #pragma once > #if 1 > #pragma omp wanna "see this" in cpp output > #else > #pragma omp nope "this one not" > #endif > > here's the initial version of my patch > > Subject: [PATCH] preprocessor: properly emit #pragma directives > > 3 months after the first commit, handling of pragma directives was > implemented, with the idea of turning the token into __pragma__ for > later internal consumption. however never anything came out of this idea, > and #pragma was basically left broken. apart from #pragma once, the > directive needs to persist in the preprocessor output, it is for later > consumption of the compiler (apparently the assumption was that sparse > would never be used as a stand-alone preprocessor). If __pragma__ exist pass the preprocessor stage. It can appear in any part of the C source file. The C parser need to consume it at almost any context. That will really complicate stuff. I think that is a bad idea. There might be other ways to do what you want. If it is pre-processor only, then that might be fine. Because there is no C parser to consume the output. Chris -- To unsubscribe from this list: send the line "unsubscribe linux-sparse" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
