From e46114fdc880cded537697a25ba0cf04f242ca82 Mon Sep 17 00:00:00 2001
From: Ben Kimock <kimockb@gmail.com>
Date: Fri, 15 Mar 2024 14:13:11 -0400
Subject: [PATCH] Handle calls to upstream monomorphizations in
 compiler_builtins

---
 src/abi/mod.rs | 14 ++++++++++++++
 src/base.rs    |  7 +++++++
 src/lib.rs     |  1 +
 3 files changed, 22 insertions(+)

diff --git a/src/abi/mod.rs b/src/abi/mod.rs
index 6e846d721f2e2..b33587f8948b9 100644
--- a/src/abi/mod.rs
+++ b/src/abi/mod.rs
@@ -8,8 +8,11 @@ use std::borrow::Cow;
 
 use cranelift_codegen::ir::SigRef;
 use cranelift_module::ModuleError;
+use rustc_codegen_ssa::errors::CompilerBuiltinsCannotCall;
 use rustc_middle::middle::codegen_fn_attrs::CodegenFnAttrFlags;
 use rustc_middle::ty::layout::FnAbiOf;
+use rustc_middle::ty::print::with_no_trimmed_paths;
+use rustc_monomorphize::is_call_from_compiler_builtins_to_upstream_monomorphization;
 use rustc_session::Session;
 use rustc_span::source_map::Spanned;
 use rustc_target::abi::call::{Conv, FnAbi};
@@ -372,6 +375,17 @@ pub(crate) fn codegen_terminator_call<'tcx>(
             ty::Instance::expect_resolve(fx.tcx, ty::ParamEnv::reveal_all(), def_id, fn_args)
                 .polymorphize(fx.tcx);
 
+        if is_call_from_compiler_builtins_to_upstream_monomorphization(fx.tcx, instance) {
+            if target.is_some() {
+                let caller = with_no_trimmed_paths!(fx.tcx.def_path_str(fx.instance.def_id()));
+                let callee = with_no_trimmed_paths!(fx.tcx.def_path_str(def_id));
+                fx.tcx.dcx().emit_err(CompilerBuiltinsCannotCall { caller, callee });
+            } else {
+                fx.bcx.ins().trap(TrapCode::User(0));
+                return;
+            }
+        }
+
         if fx.tcx.symbol_name(instance).name.starts_with("llvm.") {
             crate::intrinsics::codegen_llvm_intrinsic_call(
                 fx,
diff --git a/src/base.rs b/src/base.rs
index 2415c2c90b22c..047dc56a32ead 100644
--- a/src/base.rs
+++ b/src/base.rs
@@ -8,6 +8,7 @@ use rustc_index::IndexVec;
 use rustc_middle::ty::adjustment::PointerCoercion;
 use rustc_middle::ty::layout::FnAbiOf;
 use rustc_middle::ty::print::with_no_trimmed_paths;
+use rustc_monomorphize::is_call_from_compiler_builtins_to_upstream_monomorphization;
 
 use crate::constant::ConstantCx;
 use crate::debuginfo::FunctionDebugContext;
@@ -999,6 +1000,12 @@ fn codegen_panic_inner<'tcx>(
     let def_id = fx.tcx.require_lang_item(lang_item, span);
 
     let instance = Instance::mono(fx.tcx, def_id).polymorphize(fx.tcx);
+
+    if is_call_from_compiler_builtins_to_upstream_monomorphization(fx.tcx, instance) {
+        fx.bcx.ins().trap(TrapCode::User(0));
+        return;
+    }
+
     let symbol_name = fx.tcx.symbol_name(instance).name;
 
     fx.lib_call(
diff --git a/src/lib.rs b/src/lib.rs
index 7e2e1f7c6ac07..a59a39074f8c0 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -21,6 +21,7 @@ extern crate rustc_hir;
 extern crate rustc_incremental;
 extern crate rustc_index;
 extern crate rustc_metadata;
+extern crate rustc_monomorphize;
 extern crate rustc_session;
 extern crate rustc_span;
 extern crate rustc_target;