diff --git a/src/compiler/glsl/glsl_parser_extras.cpp b/src/compiler/glsl/glsl_parser_extras.cpp
index 94ceb5eb873..97c7b4d7820 100644
--- a/src/compiler/glsl/glsl_parser_extras.cpp
+++ b/src/compiler/glsl/glsl_parser_extras.cpp
@@ -1852,6 +1852,49 @@ set_shader_inout_layout(struct gl_shader *shader,
    shader->bound_image = state->bound_image_specified;
 }
 
+/* src can be NULL if only the symbols found in the exec_list should be
+ * copied
+ */
+void
+_mesa_glsl_copy_symbols_from_table(struct exec_list *shader_ir,
+                                   struct glsl_symbol_table *src,
+                                   struct glsl_symbol_table *dest)
+{
+   foreach_in_list (ir_instruction, ir, shader_ir) {
+      switch (ir->ir_type) {
+      case ir_type_function:
+         dest->add_function((ir_function *) ir);
+         break;
+      case ir_type_variable: {
+         ir_variable *const var = (ir_variable *) ir;
+
+         if (var->data.mode != ir_var_temporary)
+            dest->add_variable(var);
+         break;
+      }
+      default:
+         break;
+      }
+   }
+
+   if (src != NULL) {
+      /* Explicitly copy the gl_PerVertex interface definitions because these
+       * are needed to check they are the same during the interstage link.
+       * They can’t necessarily be found via the exec_list because the members
+       * might not be referenced. The GL spec still requires that they match
+       * in that case.
+       */
+      const glsl_type *iface =
+         src->get_interface("gl_PerVertex", ir_var_shader_in);
+      if (iface)
+         dest->add_interface(iface->name, iface, ir_var_shader_in);
+
+      iface = src->get_interface("gl_PerVertex", ir_var_shader_out);
+      if (iface)
+         dest->add_interface(iface->name, iface, ir_var_shader_out);
+   }
+}
+
 extern "C" {
 
 static void
diff --git a/src/compiler/glsl/glsl_parser_extras.h b/src/compiler/glsl/glsl_parser_extras.h
index fb358130878..2e98bc72e74 100644
--- a/src/compiler/glsl/glsl_parser_extras.h
+++ b/src/compiler/glsl/glsl_parser_extras.h
@@ -948,6 +948,11 @@ extern int glcpp_preprocess(void *ctx, const char **shader, char **info_log,
 extern void _mesa_destroy_shader_compiler(void);
 extern void _mesa_destroy_shader_compiler_caches(void);
 
+extern void
+_mesa_glsl_copy_symbols_from_table(struct exec_list *shader_ir,
+                                   struct glsl_symbol_table *src,
+                                   struct glsl_symbol_table *dest);
+
 #ifdef __cplusplus
 }
 #endif