Summary:
Clang -fpic defaults to -fno-semantic-interposition (GCC -fpic defaults
to -fsemantic-interposition).
Users need to specify -fsemantic-interposition to get semantic
interposition behavior.
Semantic interposition is currently a best-effort feature. There may
still be some cases where it is not handled well.
Reviewers: peter.smith, rnk, serge-sans-paille, sfertile, jfb, jdoerfert
Subscribers: dschuff, jyknight, dylanmckay, nemanjai, jvesely, kbarton, fedor.sergeev, asb, rbar, johnrusso, simoncook, sabuasal, niosHD, jrtc27, zzheng, edward-jones, atanasyan, rogfer01, MartinMosbeck, brucehoult, the_o, arphaman, PkmX, jocewei, jsji, Jim, lenary, s.egerton, pzheng, sameer.abuasal, apazos, luismarques, cfe-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D73865
Summary:
This patch implements `__builtin_is_constant_evaluated` as specifier by [P0595R2](https://wg21.link/p0595r2). It is built on the back of Bill Wendling's work for `__builtin_constant_p()`.
More tests to come, but early feedback is appreciated.
I plan to implement warnings for common mis-usages like those belowe in a following patch:
```
void foo(int x) {
if constexpr (std::is_constant_evaluated())) { // condition is always `true`. Should use plain `if` instead.
foo_constexpr(x);
} else {
foo_runtime(x);
}
}
```
Reviewers: rsmith, MaskRay, bruno, void
Reviewed By: rsmith
Subscribers: dexonsmith, zoecarver, fdeazeve, kristina, cfe-commits
Differential Revision: https://reviews.llvm.org/D55500
llvm-svn: 359067
Fangrui Song