symtab2gb: link symbol tables, not goto models

There is no need to do the additional work that linking on goto
functions entails when the input is just symbol tables. Thus link symbol
tables, and only after linking all of them generate goto functions and
then write the combined goto model.

Author: tautschnig

src/symtab2gb/module_dependencies.txt

@@ -3,3 +3,4 @@ json-symtab-language
 langapi
 goto-programs
 ansi-c
+linking

src/symtab2gb/symtab2gb_parse_options.cpp

@@ -16,11 +16,13 @@ Author: Diffblue Ltd.
 
 #include <goto-programs/goto_convert_functions.h>
 #include <goto-programs/goto_model.h>
-#include <goto-programs/link_goto_model.h>
 #include <goto-programs/write_goto_binary.h>
+
 #include <json-symtab-language/json_symtab_language.h>
 #include <langapi/mode.h>
 
+#include <linking/linking.h>
+
 #include <util/config.h>
 #include <util/exception_utils.h>
 #include <util/exit_codes.h>
@@ -67,7 +69,7 @@ static void run_symtab2gb(
   auto const symtab_language = new_json_symtab_language();
   symtab_language->set_message_handler(message_handler);
 
-  goto_modelt linked_goto_model{};
+  symbol_tablet linked_symbol_table;
 
   for(std::size_t ix = 0; ix < symtab_files.size(); ++ix)
   {
@@ -85,11 +87,18 @@ static void run_symtab2gb(
         "failed to typecheck symbol table from file '" + symtab_filename + "'"};
     }
     config.set_from_symbol_table(symtab);
-    goto_modelt goto_model{};
-    goto_model.symbol_table = symtab;
-    goto_convert(goto_model, message_handler);
-    link_goto_model(linked_goto_model, goto_model, message_handler);
+
+    if(failed(linking(linked_symbol_table, symtab, message_handler)))
+    {
+      throw invalid_source_file_exceptiont{"failed to link `" +
+                                           symtab_filename + "'"};
+    }
   }
+
+  goto_modelt linked_goto_model;
+  linked_goto_model.symbol_table.swap(linked_symbol_table);
+  goto_convert(linked_goto_model, message_handler);
+
   if(failed(write_goto_binary(out_file, linked_goto_model)))
   {
     throw system_exceptiont{"failed to write goto binary to " + gb_filename};