Make componentt::{base,pretty}_name comments

The only semantically relevant name information is the ID_name entry.
Two components should not be considered different when they only differ
in their base_name or pretty_name. Thus, use ID_C_base_name and
ID_C_pretty_name, respectively, to store these.

The goto binary version is incremented as goto binaries compiled before
this patch are incompatible with the changes introduced here.

Fixes: #5818

Author: tautschnig

regression/ansi-c/arch_flags_mcpu_bad/object.intel

@@ -1565,13 +1565,13 @@ std::string expr2ct::convert_member(
 
   if(!component_name.empty())
   {
-    const exprt &comp_expr = struct_union_type.get_component(component_name);
+    const auto &comp_expr = struct_union_type.get_component(component_name);
 
     if(comp_expr.is_nil())
       return convert_norep(src, precedence);
 
-    if(!comp_expr.get(ID_pretty_name).empty())
-      dest+=comp_expr.get_string(ID_pretty_name);
+    if(!comp_expr.get_pretty_name().empty())
+      dest += id2string(comp_expr.get_pretty_name());
     else
       dest+=id2string(component_name);
 
@@ -1583,9 +1583,12 @@ std::string expr2ct::convert_member(
   if(n>=struct_union_type.components().size())
     return convert_norep(src, precedence);
 
-  const exprt &comp_expr = struct_union_type.components()[n];
+  const auto &comp_expr = struct_union_type.components()[n];
 
-  dest+=comp_expr.get_string(ID_pretty_name);
+  if(!comp_expr.get_pretty_name().empty())
+    dest += id2string(comp_expr.get_pretty_name());
+  else
+    dest += id2string(comp_expr.get_name());
 
   return dest;
 }

regression/ansi-c/arch_flags_mcpu_good/object.arm

@@ -95,7 +95,10 @@ std::string expr2cppt::convert_struct(
 
       dest+=sep;
       dest+='.';
-      dest += c.get_string(ID_pretty_name);
+      if(!c.get_pretty_name().empty())
+        dest += id2string(c.get_pretty_name());
+      else
+        dest += id2string(c.get_name());
       dest+='=';
       dest+=tmp;
     }

regression/ansi-c/arch_flags_mthumb_bad/object.intel

@@ -81,8 +81,8 @@ void print_struct_alignment_problems(
                   << symbol_pair.second.location << '\n';
             }
 
-            out << "members " << it_mem->get_pretty_name() << " and "
-                << it_next->get_pretty_name() << " might interfere\n";
+            out << "members " << it_mem->get_name() << " and "
+                << it_next->get_name() << " might interfere\n";
           }
         }
       }

regression/ansi-c/arch_flags_mthumb_good/object.arm

@@ -12,7 +12,7 @@ Author: CM Wintersteiger
 #ifndef CPROVER_GOTO_PROGRAMS_WRITE_GOTO_BINARY_H
 #define CPROVER_GOTO_PROGRAMS_WRITE_GOTO_BINARY_H
 
-#define GOTO_BINARY_VERSION 5
+#define GOTO_BINARY_VERSION 6
 
 #include <iosfwd>
 #include <string>

src/ansi-c/expr2c.cpp

@@ -353,7 +353,7 @@ IREP_ID_TWO(mult, *)
 IREP_ID_TWO(div, /)
 IREP_ID_TWO(power, **)
 IREP_ID_ONE(factorial_power)
-IREP_ID_ONE(pretty_name)
+IREP_ID_TWO(C_pretty_name, #pretty_name)
 IREP_ID_TWO(C_class, #class)
 IREP_ID_TWO(C_field, #field)
 IREP_ID_TWO(C_interface, #interface)

src/cpp/expr2cpp.cpp

@@ -88,12 +88,12 @@ class struct_union_typet:public typet
 
     const irep_idt &get_base_name() const
     {
-      return get(ID_base_name);
+      return get(ID_C_base_name);
     }
 
     void set_base_name(const irep_idt &base_name)
     {
-      return set(ID_base_name, base_name);
+      return set(ID_C_base_name, base_name);
     }
 
     const irep_idt &get_access() const
@@ -108,12 +108,12 @@ class struct_union_typet:public typet
 
     const irep_idt &get_pretty_name() const
     {
-      return get(ID_pretty_name);
+      return get(ID_C_pretty_name);
     }
 
     void set_pretty_name(const irep_idt &name)
     {
-      return set(ID_pretty_name, name);
+      return set(ID_C_pretty_name, name);
     }
 
     bool get_anonymous() const