llvm: add assert to reliably catch undefined value use

This assert makes it possible to detect a regression of #13030 in the
future without relying on undefined value tracking.

1 files changed, 5 insertions, 2 deletions

diff --git a/src/codegen/llvm.zig b/src/codegen/llvm.zig
index 1b793265da..ffa710c67a 100644
--- a/src/codegen/llvm.zig
+++ b/src/codegen/llvm.zig
@@ -2332,10 +2332,13 @@ pub const Object = struct {
         // buffer is only used for int_type, `builtin` is a struct.
         const builtin_ty = mod.declPtr(builtin_decl).val.toType(undefined);
         const builtin_namespace = builtin_ty.getNamespace().?;
-        const stack_trace_decl = builtin_namespace.decls
+        const stack_trace_decl_index = builtin_namespace.decls
             .getKeyAdapted(stack_trace_str, Module.DeclAdapter{ .mod = mod }).?;
+        const stack_trace_decl = mod.declPtr(stack_trace_decl_index);
 
-        return mod.declPtr(stack_trace_decl).val.toType(undefined);
+        // Sema should have ensured that StackTrace was analyzed.
+        assert(stack_trace_decl.has_tv);
+        return stack_trace_decl.val.toType(undefined);
     }
 };