raw dylib: also apply the standard ABI conformance checks

also unify error messages that do not seem to have a good reason to be different

Author: RalfJung

compiler/rustc_metadata/messages.ftl

@@ -272,6 +272,9 @@ metadata_raw_dylib_no_nul =
 metadata_raw_dylib_only_windows =
     link kind `raw-dylib` is only supported on Windows targets
 
+metadata_raw_dylib_unsupported_abi =
+    ABI not supported by `#[link(kind = "raw-dylib")]` on this architecture
+
 metadata_renaming_no_link =
     renaming of the library `{$lib_name}` was specified, however this crate contains no `#[link(...)]` attributes referencing this library
 
@@ -319,12 +322,6 @@ metadata_unknown_link_modifier =
 
 metadata_unknown_target_modifier_unsafe_allowed = unknown target modifier `{$flag_name}`, requested by `-Cunsafe-allow-abi-mismatch={$flag_name}`
 
-metadata_unsupported_abi =
-    ABI not supported by `#[link(kind = "raw-dylib")]` on this architecture
-
-metadata_unsupported_abi_i686 =
-    ABI not supported by `#[link(kind = "raw-dylib")]` on i686
-
 metadata_wasm_c_abi =
     older versions of the `wasm-bindgen` crate are incompatible with current versions of Rust; please update to `wasm-bindgen` v0.2.88
 

compiler/rustc_metadata/src/errors.rs

@@ -300,15 +300,8 @@ pub struct NoLinkModOverride {
 }
 
 #[derive(Diagnostic)]
-#[diag(metadata_unsupported_abi_i686)]
-pub struct UnsupportedAbiI686 {
-    #[primary_span]
-    pub span: Span,
-}
-
-#[derive(Diagnostic)]
-#[diag(metadata_unsupported_abi)]
-pub struct UnsupportedAbi {
+#[diag(metadata_raw_dylib_unsupported_abi)]
+pub struct RawDylibUnsupportedAbi {
     #[primary_span]
     pub span: Span,
 }

compiler/rustc_metadata/src/native_libs.rs

@@ -12,6 +12,7 @@ use rustc_session::config::CrateType;
 use rustc_session::cstore::{
     DllCallingConvention, DllImport, ForeignModule, NativeLib, PeImportNameType,
 };
+use rustc_session::lint::builtin::UNSUPPORTED_CALLING_CONVENTIONS;
 use rustc_session::parse::feature_err;
 use rustc_session::search_paths::PathKind;
 use rustc_session::utils::NativeLibKind;
@@ -652,7 +653,23 @@ impl<'tcx> Collector<'tcx> {
     ) -> DllImport {
         let span = self.tcx.def_span(item);
 
-        // this logic is similar to `Target::adjust_abi` (in rustc_target/src/spec/mod.rs) but errors on unsupported inputs
+        // Check whether this ABI is generally supported.
+        match self.tcx.sess.target.is_abi_supported(abi) {
+            Some(true) => (),
+            Some(false) => {
+                self.tcx.dcx().emit_fatal(errors::RawDylibUnsupportedAbi { span });
+            }
+            None => {
+                let hir_id = self.tcx.local_def_id_to_hir_id(item.expect_local());
+                self.tcx.node_span_lint(UNSUPPORTED_CALLING_CONVENTIONS, hir_id, span, |lint| {
+                    lint.primary_message("use of calling convention not supported on this target");
+                });
+            }
+        }
+
+        // This logic is similar to `Target::adjust_abi` (in rustc_target/src/spec/mod.rs) but we
+        // need more detail than those adjustments, and we can't support all ABIs that are generally
+        // supported.
         let calling_convention = if self.tcx.sess.target.arch == "x86" {
             match abi {
                 ExternAbi::C { .. } | ExternAbi::Cdecl { .. } => DllCallingConvention::C,
@@ -679,7 +696,7 @@ impl<'tcx> Collector<'tcx> {
                     DllCallingConvention::Vectorcall(self.i686_arg_list_size(item))
                 }
                 _ => {
-                    self.tcx.dcx().emit_fatal(errors::UnsupportedAbiI686 { span });
+                    self.tcx.dcx().emit_fatal(errors::RawDylibUnsupportedAbi { span });
                 }
             }
         } else {
@@ -688,7 +705,7 @@ impl<'tcx> Collector<'tcx> {
                     DllCallingConvention::C
                 }
                 _ => {
-                    self.tcx.dcx().emit_fatal(errors::UnsupportedAbi { span });
+                    self.tcx.dcx().emit_fatal(errors::RawDylibUnsupportedAbi { span });
                 }
             }
         };