Merge pull request diffblue#405 from diffblue/feature/remove-find_or_create_symbol_expr

Don't use find_or_create_symbol_expr for symbols that must already exist

Author: NathanJPhillips

src/taint-analysis/taint_program.cpp

@@ -1,4 +1,4 @@
-// Copyright 2016-2017 Diffblue Limited. All Rights Reserved.
+// Copyright 2016-2018 Diffblue Limited. All Rights Reserved.
 
 /// \file
 /// taint_programt
@@ -12,11 +12,6 @@
 #include <analyses/call_graph_helpers.h>
 #include <unordered_set>
 
-extern symbol_exprt find_or_create_symbol_expr(
-  const namespacet &ns,
-  const irep_idt &symbol_name,
-  const typet &symbol_type);
-
 static void build_NONDET_retvals_replacements(
   const goto_modelt &model,
   const namespacet &ns,
@@ -98,9 +93,6 @@ static void build_NONDET_retvals_replacements(
       const irep_idt &callee_ident=
         to_symbol_expr(fn_call.function()).get_identifier();
 
-      const code_typet &fn_type=
-        model.goto_functions.function_map.at(callee_ident).type;
-
       const code_assignt &asgn=to_code_assign(next_instr_it->code);
       if(asgn.rhs().id()!=ID_side_effect)
         continue;
@@ -110,10 +102,7 @@ static void build_NONDET_retvals_replacements(
       replacements.insert(
         {
           next_instr_it,
-          find_or_create_symbol_expr(
-            ns,
-            as_string(callee_ident)+RETURN_VALUE_SUFFIX,
-            fn_type.return_type())
+          ns.lookup(id2string(callee_ident) + RETURN_VALUE_SUFFIX).symbol_expr()
         });
     }
   }

src/taint-analysis/taint_summary.cpp

@@ -342,22 +342,6 @@ std::string taint_summaryt::description() const noexcept
 ///
 ////////////////////////////////////////////////////////////////////////////////
 
-
-symbol_exprt find_or_create_symbol_expr(
-  const namespacet &ns,
-  const irep_idt &symbol_name,
-  const typet &symbol_type)
-{
-  const symbolt *symbol_ptr;
-  if(ns.lookup(symbol_name, symbol_ptr))
-  {
-    assert(false);
-    return symbol_exprt(symbol_name, symbol_type);
-  }
-  assert(symbol_ptr!=nullptr);
-  return symbol_ptr->symbol_expr();
-}
-
 /// \brief If the passed expression in a non-null pointer expression, then
 /// the dereference expression is returned. Otherwise the original expression
 /// is returned.
@@ -1096,7 +1080,7 @@ numbered_lvalue_to_taint_mapt taint_algorithm_computing_summary_of_functiont::
       if(callee_expr.id()==ID_symbol)
       {
         irep_idt callee_id = to_symbol_expr(callee_expr).get_identifier();
-        const std::string callee_ident = as_string(callee_id);
+        const std::string &callee_ident = as_string(callee_id);
         const code_typet &fn_type =
           program->get_functions().function_map.at(callee_id).type;
         if(database.contains(callee_id))
@@ -1187,10 +1171,8 @@ numbered_lvalue_to_taint_mapt taint_algorithm_computing_summary_of_functiont::
                 &result_location))
             {
               // Update of return_value of the callee.
-              result_lvalue = find_or_create_symbol_expr(
-                program->get_namespace(),
-                callee_ident + RETURN_VALUE_SUFFIX,
-                fn_type.return_type());
+              result_lvalue = program->get_namespace()
+                .lookup(callee_ident + RETURN_VALUE_SUFFIX).symbol_expr();
             }
             else if(
               const taintable_location_argumentt *result_argument =
@@ -1253,10 +1235,8 @@ numbered_lvalue_to_taint_mapt taint_algorithm_computing_summary_of_functiont::
                 &sanitized_location))
             {
               // Update of return_value of the callee.
-              result_lvalue = find_or_create_symbol_expr(
-                program->get_namespace(),
-                callee_ident + RETURN_VALUE_SUFFIX,
-                fn_type.return_type());
+              result_lvalue = program->get_namespace()
+                .lookup(callee_ident + RETURN_VALUE_SUFFIX).symbol_expr();
             }
             else if(
               const taintable_location_argumentt *sanitized_argument =