raw dylib: ensure that we have applied standard ABI 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

@@ -652,7 +652,13 @@ 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
+        // This `extern` block should have been checked for general ABI support before, but let's
+        // double-check that.
+        assert!(self.tcx.sess.target.is_abi_supported(abi));
+
+        // This logic is similar to `AbiMap::canonize_abi` (in rustc_target/src/spec/abi_map.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 +685,7 @@ 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 +694,7 @@ impl<'tcx> Collector<'tcx> {
                     DllCallingConvention::C
                 }
                 _ => {
-                    self.tcx.dcx().emit_fatal(errors::UnsupportedAbi { span });
+                    self.tcx.dcx().emit_fatal(errors::RawDylibUnsupportedAbi { span });
                 }
             }
         };

tests/ui/abi/unsupported.rs

@@ -284,3 +284,9 @@ fn cmse_entry_ptr(f: extern "C-cmse-nonsecure-entry" fn()) {
 }
 extern "C-cmse-nonsecure-entry" {}
 //~^ ERROR is not a supported ABI
+
+#[cfg(windows)]
+#[link(name = "foo", kind = "raw-dylib")]
+extern "cdecl" {}
+//[x64_win]~^ WARN use of calling convention not supported on this target
+//[x64_win]~^^ WARN this was previously accepted

tests/ui/abi/unsupported.x64_win.stderr

@@ -150,6 +150,15 @@ error[E0570]: `"C-cmse-nonsecure-entry"` is not a supported ABI for the current
 LL | extern "C-cmse-nonsecure-entry" {}
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
+warning: use of calling convention not supported on this target
+  --> $DIR/unsupported.rs:290:1
+   |
+LL | extern "cdecl" {}
+   | ^^^^^^^^^^^^^^^^^
+   |
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+   = note: for more information, see issue #137018 <https://github.com/rust-lang/rust/issues/137018>
+
 error[E0570]: `"ptx-kernel"` is not a supported ABI for the current target
   --> $DIR/unsupported.rs:36:1
    |
@@ -216,7 +225,7 @@ error[E0570]: `"C-cmse-nonsecure-entry"` is not a supported ABI for the current
 LL | extern "C-cmse-nonsecure-entry" fn cmse_entry() {}
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
-error: aborting due to 15 previous errors; 14 warnings emitted
+error: aborting due to 15 previous errors; 15 warnings emitted
 
 For more information about this error, try `rustc --explain E0570`.
 Future incompatibility report: Future breakage diagnostic:
@@ -351,6 +360,17 @@ LL | fn cmse_entry_ptr(f: extern "C-cmse-nonsecure-entry" fn()) {
    = note: for more information, see issue #130260 <https://github.com/rust-lang/rust/issues/130260>
    = note: `#[warn(unsupported_fn_ptr_calling_conventions)]` on by default
 
+Future breakage diagnostic:
+warning: use of calling convention not supported on this target
+  --> $DIR/unsupported.rs:290:1
+   |
+LL | extern "cdecl" {}
+   | ^^^^^^^^^^^^^^^^^
+   |
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+   = note: for more information, see issue #137018 <https://github.com/rust-lang/rust/issues/137018>
+   = note: `#[warn(unsupported_calling_conventions)]` on by default
+
 Future breakage diagnostic:
 warning: use of calling convention not supported on this target
   --> $DIR/unsupported.rs:176:1