aaron.ballman added inline comments.
================ Comment at: test/Sema/attr-nocf_check.c:18-20 + FuncPointerWithNoCfCheck fNoCfCheck = f; // no-warning + (*fNoCfCheck)(); // no-warning + f = fNoCfCheck; // no-warning ---------------- oren_ben_simhon wrote: > aaron.ballman wrote: > > oren_ben_simhon wrote: > > > aaron.ballman wrote: > > > > oren_ben_simhon wrote: > > > > > aaron.ballman wrote: > > > > > > These are an error in GCC and I think we should match that > > > > > > behavior. https://godbolt.org/g/r3pf4X > > > > > I will create a warning however in LLVM we don't create an error upon > > > > > incompatible pointer due to function attribute types. > > > > It should be an error -- Clang does error on this sort of thing when > > > > appropriate (which I believe it is, here). For instance, calling > > > > convention attributes do this: https://godbolt.org/g/mkTGLg > > > In Clang there is Sema::IncompatiblePointer in case to pointers are not > > > compatible. This flag emits warning message. In the time i check for > > > pointer incompatibility (checkPointerTypesForAssignment()), i don;t have > > > a handle to the attributes. Any suggestion how to implement the exception > > > for nocf_check attribute? > > I believe this is handled in `ASTContext::mergeFunctionType()`. See: > > ``` > > // Compatible functions must have compatible calling conventions > > if (lbaseInfo.getCC() != rbaseInfo.getCC()) > > return QualType(); > > ``` > > Somewhere around there is likely where you should be. > I already added there getnocfcheck. > > After double checking, I see that nocf_check behavior is identical to other > function attributes. > For some reason in the clang tests they give warning but in godbolt it gives > an error. > I am not sure what is the difference between the flags in godbolt and in my > test but this is what causing the warning/error message difference. > > So basically my behavior is identical to other function type attributes (e.g. > no_caller_saved_registers). I believe it is also identical to GCC but i can't > prove it because i don't know the flags that godbolt is using. > You can see the flags being passed in godbolt by passing -v on the command line. FWIW, I get the same error behavior elsewhere as well: http://coliru.stacked-crooked.com/a/d28234385fa68374 https://wandbox.org/permlink/SRLM82l2uJ8q3o1Q I think you should do some more investigation into what's going on there. Ultimately, I want to avoid clang accepting the `nocf_check` attribute (even with a warning) in cases where GCC doesn't accept it, because that leads to incompatibilities when switching between the two compilers. We should accept what GCC accepts and reject what GCC rejects unless there's a good reason to deviate. Repository: rL LLVM https://reviews.llvm.org/D41880 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
