Set base_name member for __CPROVER_start

The (un)reachable functions output uses the base_name in the output,
which previously resulted in the surprising behaviour that an empty
function name was printed. While falling back to the symbol's name may
be possible, there could well be other places that try to use the
`base_name`.

Author: tautschnig

jbmc/src/java_bytecode/java_entry_point.cpp

@@ -767,6 +767,7 @@ bool generate_java_start_function(
   symbolt new_symbol;
 
   new_symbol.name=goto_functionst::entry_point();
+  new_symbol.base_name = goto_functionst::entry_point();
   new_symbol.type = java_method_typet({}, java_void_type());
   new_symbol.value.swap(init_code);
   new_symbol.mode=ID_java;

regression/goto-analyzer/reachable-functions-basic-json/test.desc

@@ -10,3 +10,4 @@ CORE
 --
 "last line":[[:space:]]*$
 ^warning: ignoring
+"function": ""

regression/goto-analyzer/reachable-functions-basic-text/test.desc

@@ -9,3 +9,4 @@ unreachable.c not_obviously_dead 25 31$
 ^SIGNAL=0$
 --
 ^warning: ignoring
+^ 35$

src/ansi-c/ansi_c_entry_point.cpp

@@ -535,6 +535,7 @@ bool generate_ansi_c_start_function(
   symbolt new_symbol;
 
   new_symbol.name=goto_functionst::entry_point();
+  new_symbol.base_name = goto_functionst::entry_point();
   new_symbol.type = code_typet({}, void_type());
   new_symbol.value.swap(init_code);
   new_symbol.mode=symbol.mode;

src/jsil/jsil_entry_point.cpp

@@ -152,6 +152,7 @@ bool jsil_entry_point(
   symbolt new_symbol;
 
   new_symbol.name=goto_functionst::entry_point();
+  new_symbol.base_name = goto_functionst::entry_point();
   new_symbol.type = code_typet({}, empty_typet());
   new_symbol.value.swap(init_code);
 

src/statement-list/statement_list_entry_point.cpp

@@ -180,6 +180,7 @@ bool generate_statement_list_start_function(
   // Add the start symbol.
   symbolt start_symbol;
   start_symbol.name = goto_functionst::entry_point();
+  start_symbol.base_name = goto_functionst::entry_point();
   start_symbol.type = code_typet({}, empty_typet{});
   start_symbol.value.swap(start_function_body);
   start_symbol.mode = main.mode;

unit/analyses/ai/ai.cpp

@@ -233,6 +233,7 @@ SCENARIO(
 
   symbolt start;
   start.name = goto_functionst::entry_point();
+  start.base_name = goto_functionst::entry_point();
   start.mode = ID_C;
   start.type = code_typet({}, empty_typet());
   start.value = make_void_call(f.symbol_expr());