diff options
| -rw-r--r-- | compiler/rustc_mir/src/transform/check_unsafety.rs | 6 | ||||
| -rw-r--r-- | compiler/rustc_mir_build/src/check_unsafety.rs | 17 | ||||
| -rw-r--r-- | compiler/rustc_typeck/src/collect.rs | 16 | ||||
| -rw-r--r-- | src/test/ui/target-feature/wasm-safe.rs | 44 |
4 files changed, 75 insertions, 8 deletions
diff --git a/compiler/rustc_mir/src/transform/check_unsafety.rs b/compiler/rustc_mir/src/transform/check_unsafety.rs index 955be8cc81e..9a4e51203d2 100644 --- a/compiler/rustc_mir/src/transform/check_unsafety.rs +++ b/compiler/rustc_mir/src/transform/check_unsafety.rs @@ -376,6 +376,12 @@ impl<'a, 'tcx> UnsafetyChecker<'a, 'tcx> { /// Checks whether calling `func_did` needs an `unsafe` context or not, i.e. whether /// the called function has target features the calling function hasn't. fn check_target_features(&mut self, func_did: DefId) { + // Unsafety isn't required on wasm targets. For more information see + // the corresponding check in typeck/src/collect.rs + if self.tcx.sess.target.options.is_like_wasm { + return; + } + let callee_features = &self.tcx.codegen_fn_attrs(func_did).target_features; let self_features = &self.tcx.codegen_fn_attrs(self.body_did).target_features; diff --git a/compiler/rustc_mir_build/src/check_unsafety.rs b/compiler/rustc_mir_build/src/check_unsafety.rs index d1aaabe92ed..2d52577829c 100644 --- a/compiler/rustc_mir_build/src/check_unsafety.rs +++ b/compiler/rustc_mir_build/src/check_unsafety.rs @@ -166,13 +166,16 @@ impl<'a, 'tcx> Visitor<'a, 'tcx> for UnsafetyVisitor<'a, 'tcx> { self.requires_unsafe(expr.span, CallToUnsafeFunction); } else if let &ty::FnDef(func_did, _) = self.thir[fun].ty.kind() { // If the called function has target features the calling function hasn't, - // the call requires `unsafe`. - if !self - .tcx - .codegen_fn_attrs(func_did) - .target_features - .iter() - .all(|feature| self.body_target_features.contains(feature)) + // the call requires `unsafe`. Don't check this on wasm + // targets, though. For more information on wasm see the + // is_like_wasm check in typeck/src/collect.rs + if !self.tcx.sess.target.options.is_like_wasm + && !self + .tcx + .codegen_fn_attrs(func_did) + .target_features + .iter() + .all(|feature| self.body_target_features.contains(feature)) { self.requires_unsafe(expr.span, CallToFunctionWith); } diff --git a/compiler/rustc_typeck/src/collect.rs b/compiler/rustc_typeck/src/collect.rs index 0528f8812f9..5d83375e5a1 100644 --- a/compiler/rustc_typeck/src/collect.rs +++ b/compiler/rustc_typeck/src/collect.rs @@ -2770,7 +2770,21 @@ fn codegen_fn_attrs(tcx: TyCtxt<'_>, id: DefId) -> CodegenFnAttrs { } } else if tcx.sess.check_name(attr, sym::target_feature) { if !tcx.is_closure(id) && tcx.fn_sig(id).unsafety() == hir::Unsafety::Normal { - if !tcx.features().target_feature_11 { + if tcx.sess.target.is_like_wasm { + // The `#[target_feature]` attribute is allowed on + // WebAssembly targets on all functions, including safe + // ones. Other targets require that `#[target_feature]` is + // only applied to unsafe funtions (pending the + // `target_feature_11` feature) because on most targets + // execution of instructions that are not supported is + // considered undefined behavior. For WebAssembly which is a + // 100% safe target at execution time it's not possible to + // execute undefined instructions, and even if a future + // feature was added in some form for this it would be a + // deterministic trap. There is no undefined behavior when + // executing WebAssembly so `#[target_feature]` is allowed + // on safe functions (but again, only for WebAssembly) + } else if !tcx.features().target_feature_11 { let mut err = feature_err( &tcx.sess.parse_sess, sym::target_feature_11, diff --git a/src/test/ui/target-feature/wasm-safe.rs b/src/test/ui/target-feature/wasm-safe.rs new file mode 100644 index 00000000000..4b868684a52 --- /dev/null +++ b/src/test/ui/target-feature/wasm-safe.rs @@ -0,0 +1,44 @@ +// only-wasm32 +// check-pass + +#![feature(wasm_target_feature)] +#![allow(dead_code)] + +#[target_feature(enable = "nontrapping-fptoint")] +fn foo() {} + +#[target_feature(enable = "nontrapping-fptoint")] +extern "C" fn bar() {} + +trait A { + fn foo(); + fn bar(&self); +} + +struct B; + +impl B { + #[target_feature(enable = "nontrapping-fptoint")] + fn foo() {} + #[target_feature(enable = "nontrapping-fptoint")] + fn bar(&self) {} +} + +impl A for B { + #[target_feature(enable = "nontrapping-fptoint")] + fn foo() {} + #[target_feature(enable = "nontrapping-fptoint")] + fn bar(&self) {} +} + +fn no_features_enabled_on_this_function() { + bar(); + foo(); + B.bar(); + B::foo(); + <B as A>::foo(); + <B as A>::bar(&B); +} + +#[target_feature(enable = "nontrapping-fptoint")] +fn main() {} |