Filter out items other than non-generic functions and statics in our version of exported_symbols

src/bin/miri.rs

@@ -19,7 +19,7 @@ use log::debug;
 
 use rustc_driver::Compilation;
 use rustc_errors::emitter::{ColorConfig, HumanReadableErrorType};
-use rustc_hir::def_id::LOCAL_CRATE;
+use rustc_hir::{self as hir, def_id::LOCAL_CRATE, Node};
 use rustc_interface::interface::Config;
 use rustc_middle::{
     middle::exported_symbols::{ExportedSymbol, SymbolExportLevel},
@@ -109,12 +109,27 @@ impl rustc_driver::Callbacks for MiriBeRustCompilerCalls {
                         // https://github.com/rust-lang/rust/blob/2962e7c0089d5c136f4e9600b7abccfbbde4973d/compiler/rustc_codegen_ssa/src/back/symbol_export.rs#L62-L63
                         // https://github.com/rust-lang/rust/blob/2962e7c0089d5c136f4e9600b7abccfbbde4973d/compiler/rustc_codegen_ssa/src/back/symbol_export.rs#L174
                         tcx.reachable_set(()).iter().filter_map(|&local_def_id| {
-                            tcx.codegen_fn_attrs(local_def_id)
-                                .contains_extern_indicator()
-                                .then_some((
-                                    ExportedSymbol::NonGeneric(local_def_id.to_def_id()),
-                                    SymbolExportLevel::C,
-                                ))
+                            // Do the same filtering that rustc does:
+                            // https://github.com/rust-lang/rust/blob/2962e7c0089d5c136f4e9600b7abccfbbde4973d/compiler/rustc_codegen_ssa/src/back/symbol_export.rs#L84-L102
+                            // Otherwise it may cause unexpected behaviours and ICEs
+                            // (https://github.com/rust-lang/rust/issues/86261).
+                            let is_reachable_non_generic = matches!(
+                                tcx.hir().get(tcx.hir().local_def_id_to_hir_id(local_def_id)),
+                                Node::Item(&hir::Item {
+                                    kind: hir::ItemKind::Static(..) | hir::ItemKind::Fn(..),
+                                    ..
+                                }) | Node::ImplItem(&hir::ImplItem {
+                                    kind: hir::ImplItemKind::Fn(..),
+                                    ..
+                                })
+                                if !tcx.generics_of(local_def_id).requires_monomorphization(tcx)
+                            );
+                            (is_reachable_non_generic
+                                && tcx.codegen_fn_attrs(local_def_id).contains_extern_indicator())
+                            .then_some((
+                                ExportedSymbol::NonGeneric(local_def_id.to_def_id()),
+                                SymbolExportLevel::C,
+                            ))
                         }),
                     )
                 }

src/shims/foreign_items.rs

@@ -177,7 +177,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
                                 second_crate: tcx.crate_name(cnum),
                             });
                         }
-                        if tcx.def_kind(def_id) != DefKind::Fn {
+                        if !matches!(tcx.def_kind(def_id), DefKind::Fn | DefKind::AssocFn) {
                             throw_ub_format!(
                                 "attempt to call an exported symbol that is not defined as a function"
                             );

test-cargo-miri/Cargo.toml

@@ -15,6 +15,7 @@ issue_1567 = { path = "issue-1567" }
 issue_1691 = { path = "issue-1691" }
 issue_1705 = { path = "issue-1705" }
 issue_1760 = { path = "issue-1760" }
+issue_rust_86261 = { path = "issue-rust-86261" }
 
 [dev-dependencies]
 rand = { version = "0.8", features = ["small_rng"] }

test-cargo-miri/exported-symbol-dep/src/lib.rs

@@ -2,3 +2,12 @@
 fn exported_symbol() -> i32 {
     123456
 }
+
+pub struct AssocFn;
+
+impl AssocFn {
+    #[no_mangle]
+    pub fn assoc_fn_as_exported_symbol() -> i32 {
+        -123456
+    }
+}

test-cargo-miri/issue-rust-86261/Cargo.toml

@@ -0,0 +1,5 @@
+[package]
+name = "issue_rust_86261"
+version = "0.1.0"
+authors = ["Miri Team"]
+edition = "2018"

test-cargo-miri/issue-rust-86261/src/lib.rs

@@ -0,0 +1,23 @@
+#![allow(unused_imports, unused_attributes, no_mangle_generic_items)]
+
+// Regression test for https://github.com/rust-lang/rust/issues/86261:
+// `#[no_mangle]` on a `use` item.
+#[no_mangle]
+use std::{thread,panic, io, boxed, any, string};
+
+// `#[no_mangle]` on a struct has a similar problem.
+#[no_mangle]
+pub struct NoMangleStruct;
+
+// If `#[no_mangle]` has effect on the `struct` above, calling `NoMangleStruct` will fail with
+// "multiple definitions of symbol `NoMangleStruct`" error.
+#[export_name = "NoMangleStruct"]
+fn no_mangle_struct() {}
+
+// `#[no_mangle]` on a generic function can also cause ICEs.
+#[no_mangle]
+fn no_mangle_generic<T>() {}
+
+// Same as `no_mangle_struct()` but for the `no_mangle_generic()` generic function.
+#[export_name = "no_mangle_generic"]
+fn no_mangle_generic2() {}

test-cargo-miri/src/main.rs

@@ -62,15 +62,22 @@ mod test {
     fn exported_symbol() {
         extern crate cargo_miri_test;
         extern crate exported_symbol;
+        extern crate issue_rust_86261;
         // Test calling exported symbols in (transitive) dependencies.
         // Repeat calls to make sure the `Instance` cache is not broken.
         for _ in 0..3 {
             extern "Rust" {
                 fn exported_symbol() -> i32;
+                fn assoc_fn_as_exported_symbol() -> i32;
                 fn make_true() -> bool;
+                fn NoMangleStruct();
+                fn no_mangle_generic();
             }
             assert_eq!(unsafe { exported_symbol() }, 123456);
+            assert_eq!(unsafe { assoc_fn_as_exported_symbol() }, -123456);
             assert!(unsafe { make_true() });
+            unsafe { NoMangleStruct() }
+            unsafe { no_mangle_generic() }
         }
     }
 }