X-Git-Url: https://git.lizzy.rs/?a=blobdiff_plain;f=src%2Ftools%2Fmiri%2Fsrc%2Fhelpers.rs;h=527d31d1f0ae8acc199671562b425742a8a0eb15;hb=333ee6c466972185973d5097f8b5fb0f9fb13fa5;hp=c11c6104c2843474c4a253216daedc471d66ebb0;hpb=c1f8a3ffb2b9b155b400a675727ebd470938805c;p=rust.git

diff --git a/src/tools/miri/src/helpers.rs b/src/tools/miri/src/helpers.rs
index c11c6104c28..527d31d1f0a 100644
--- a/src/tools/miri/src/helpers.rs
+++ b/src/tools/miri/src/helpers.rs
@@ -943,7 +943,16 @@ fn check_abi_and_shim_symbol_clash(
         link_name: Symbol,
     ) -> InterpResult<'tcx, ()> {
         self.check_abi(abi, exp_abi)?;
-        if let Some((body, _)) = self.eval_context_mut().lookup_exported_symbol(link_name)? {
+        if let Some((body, instance)) = self.eval_context_mut().lookup_exported_symbol(link_name)? {
+            // If compiler-builtins is providing the symbol, then don't treat it as a clash.
+            // We'll use our built-in implementation in `emulate_foreign_item_by_name` for increased
+            // performance. Note that this means we won't catch any undefined behavior in
+            // compiler-builtins when running other crates, but Miri can still be run on
+            // compiler-builtins itself (or any crate that uses it as a normal dependency)
+            if self.eval_context_ref().tcx.is_compiler_builtins(instance.def_id().krate) {
+                return Ok(());
+            }
+
             throw_machine_stop!(TerminationInfo::SymbolShimClashing {
                 link_name,
                 span: body.span.data(),