hfinkel added a comment. In https://reviews.llvm.org/D47849#1184388, @Hahnfeld wrote:
> In https://reviews.llvm.org/D47849#1184367, @hfinkel wrote: > > > The problem is that the inline assembly might actually be for the target, > > instead of the host, because we also have target preprocessor macros > > defined, and it's going to be hard to tell. I'm not sure that there's a > > great solution here, and I agree that having something more general than > > undefining some specific things that happen to matter for math.h would be > > better. As you point out, this is not just a system-header problem. We > > might indeed want to undefine all of the target-feature-related macros > > (although that won't always be sufficient, because we need basic arch > > macros for the system headers to work at all, and those are generally > > enough to guard some inline asm). > > > I think there was a reason for pulling in the host defines. I'd have to look > at the commit message though... As I recall, it's mostly to make glibc's bits/wordsize.h work. > > >> Maybe the following makes sense: Only define the host macros, minus >> target-feature ones, when compiling for the target in the context of the >> system headers. That makes the system headers work while providing a "clean" >> preprocessor environment for the rest of the code (and, thus, retains our >> ability to complain about bad inline asm). > > I'm not sure how that's going to help with Eigen: Just including `Eigen/Core` > will pull in the other header file I mentioned with inline assembly. That's > completely independent of preprocessor macros, I think it's enough the > library's build system detected the host architecture during install. I don't see any good way to satisfy Eigen in that form. I think that we'll need to update it to understand not to use host inline as when compiling for a target. Repository: rC Clang https://reviews.llvm.org/D47849 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
