Fix the ordering in which symbols are initialised

In memory-snapshot-harness: so that pointer to objects are initialised after
those objects.

Author: petr-bauch

src/goto-harness/memory_snapshot_harness_generator.cpp

@@ -207,6 +207,18 @@ size_t memory_snapshot_harness_generatort::pointer_depth(const typet &t) const
     return pointer_depth(t.subtype()) + 1;
 }
 
+bool memory_snapshot_harness_generatort::refers_to(
+  const exprt &expr,
+  const irep_idt &name) const
+{
+  if(expr.id() == ID_symbol)
+    return to_symbol_expr(expr).get_identifier() == name;
+  return std::any_of(
+    expr.operands().begin(),
+    expr.operands().end(),
+    [this, name](const exprt &subexpr) { return refers_to(subexpr, name); });
+}
+
 code_blockt memory_snapshot_harness_generatort::add_assignments_to_globals(
   const symbol_tablet &snapshot,
   goto_modelt &goto_model) const
@@ -230,8 +242,11 @@ code_blockt memory_snapshot_harness_generatort::add_assignments_to_globals(
     ordered_snapshot_symbols.begin(),
     ordered_snapshot_symbols.end(),
     [this](const snapshot_pairt &left, const snapshot_pairt &right) {
-      return pointer_depth(left.second.symbol_expr().type()) <
-             pointer_depth(right.second.symbol_expr().type());
+      if(refers_to(right.second.value, left.first))
+        return true;
+      else
+        return pointer_depth(left.second.symbol_expr().type()) <
+               pointer_depth(right.second.symbol_expr().type());
     });
 
   code_blockt code;

src/goto-harness/memory_snapshot_harness_generator.h

@@ -244,6 +244,12 @@ class memory_snapshot_harness_generatort : public goto_harness_generatort
   /// \return pointer depth of type \p t
   size_t pointer_depth(const typet &t) const;
 
+  /// Recursively test pointer reference
+  /// \param expr: expression to be tested
+  /// \param name: name to be located
+  /// \return true if \p expr refers to an object named \p name
+  bool refers_to(const exprt &expr, const irep_idt &name) const;
+
   /// data to store the command-line options
   std::string memory_snapshot_file;
   std::string initial_goto_location_line;