fix tail calls to #[track_caller] functions

compiler/rustc_codegen_ssa/src/mir/block.rs

@@ -5,6 +5,7 @@ use rustc_ast as ast;
 use rustc_ast::{InlineAsmOptions, InlineAsmTemplatePiece};
 use rustc_data_structures::packed::Pu128;
 use rustc_hir::lang_items::LangItem;
+use rustc_lint_defs::builtin::TAIL_CALL_TRACK_CALLER;
 use rustc_middle::mir::{self, AssertKind, InlineAsmMacro, SwitchTargets, UnwindTerminateReason};
 use rustc_middle::ty::layout::{HasTyCtxt, LayoutOf, ValidityRequirement};
 use rustc_middle::ty::print::{with_no_trimmed_paths, with_no_visible_paths};
@@ -906,7 +907,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
                     fn_span,
                 );
 
-                let instance = match instance.def {
+                match instance.def {
                     // We don't need AsyncDropGlueCtorShim here because it is not `noop func`,
                     // it is `func returning noop future`
                     ty::InstanceKind::DropGlue(_, None) => {
@@ -995,14 +996,35 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
                                         intrinsic.name,
                                     );
                                 }
-                                instance
+                                (Some(instance), None)
                             }
                         }
                     }
-                    _ => instance,
-                };
 
-                (Some(instance), None)
+                    _ if kind == CallKind::Tail
+                        && instance.def.requires_caller_location(bx.tcx()) =>
+                    {
+                        if let Some(hir_id) =
+                            terminator.source_info.scope.lint_root(&self.mir.source_scopes)
+                        {
+                            let msg = "tail calling a function marked with `#[track_caller]` has no special effect";
+                            bx.tcx().node_lint(TAIL_CALL_TRACK_CALLER, hir_id, |d| {
+                                _ = d.primary_message(msg).span(fn_span)
+                            });
+                        }
+
+                        let instance = ty::Instance::resolve_for_fn_ptr(
+                            bx.tcx(),
+                            bx.typing_env(),
+                            def_id,
+                            generic_args,
+                        )
+                        .unwrap();
+
+                        (None, Some(bx.get_fn_addr(instance)))
+                    }
+                    _ => (Some(instance), None),
+                }
             }
             ty::FnPtr(..) => (None, Some(callee.immediate())),
             _ => bug!("{} is not callable", callee.layout.ty),