rjmccall added a comment. In D76937#1950764 <https://reviews.llvm.org/D76937#1950764>, @yaxunl wrote:
> In D76937#1950077 <https://reviews.llvm.org/D76937#1950077>, @rjmccall wrote: > > > Can you explain what exactly the emission/semantic model is for variables? > > Normal code-generation absolutely triggers the emission of many variables > > lazily (e.g. internal-linkage globals, C++ inline variables); and any > > variable that's *not* being emitted lazily actually needs to be treated as > > a potential root into the delayed-diagnostic graph. > > > Currently only in the following case a global variable can change the > emission state of a function: > > int foobar3() { return 1; } > #pragma omp declare target > int (*C)() = &foobar3; > #pragma omp end declare target > > > The global variable needs to be in a omp declare target directive. Its > initializer references a host function. > > This will cause the function emitted in device compilation. > > This is not transitive for variable declaration/references, e.g. the > following case will not cause foobar3 to be emitted in device compilation, > unless variable C itself is enclosed in omp declare target directive. > > int foobar3() { return 1; } > int (*C)() = &foobar3; > #pragma omp declare target > int (*D)() = C; > #pragma omp end declare target > > > Since we logged all such variable declarations in > DeclsToCheckForDeferredDiags, we only need to check variables decls in > DeclsToCheckForDeferredDiags and do not need to check variable decls in > DeclRefExpr. Okay. There are other AST nodes besides `DeclRefExpr` that can cause an ODR-use of a `VarDecl`; you could add special cases for them, too, but part of the point of this design is so that you can stop worrying about that kind of thing. I think I've said this before, but you're making things harder for yourself by re-using `visitUsedDecl` as both the "callback" of the `UsedDeclVisitor` and the original method that you call for things from `DeclsToCheckForDeferredDiags`. Just use `visitUsedDecl` for the former, make a new method for the latter, and extract any common logic you want (e.g. for `FunctionDecl`s) into helper methods that both of them can use. That way you can just unconditionally ignore non-functions in `visitUsedDecl`, assert that `DeclsToCheckForDeferredDiags` only contains the kinds of declarations you think it should, and so on. CHANGES SINCE LAST ACTION https://reviews.llvm.org/D76937/new/ https://reviews.llvm.org/D76937 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
