Filter out illegal characters from identifiers in typecheck_expr.

This change removes some characters, like "*{}", from
identifier names that were autogenerated. The reason for
this is that these names are now being passed on to other
tools, and they cause these to fail with parsing errors.

Author: NlightNFotis

src/ansi-c/c_typecheck_expr.cpp

@@ -1890,16 +1890,18 @@ void c_typecheck_baset::typecheck_side_effect_function_call(
         INVARIANT(
           !parameters.empty(),
           "GCC polymorphic built-ins should have at least one parameter");
+        /// XXX why are we only looking at the type of the first parameter?
         if(parameters.front().type().id() == ID_pointer)
         {
           identifier_with_type =
             id2string(identifier) + "_" +
-            type2name(parameters.front().type().subtype(), *this);
+            type2identifier(parameters.front().type().subtype(), *this);
         }
         else
         {
-          identifier_with_type = id2string(identifier) + "_" +
-                                 type2name(parameters.front().type(), *this);
+          identifier_with_type =
+            id2string(identifier) + "_" +
+            type2identifier(parameters.front().type(), *this);
         }
         gcc_polymorphic->set_identifier(identifier_with_type);
 

src/ansi-c/type2name.cpp

@@ -272,3 +272,32 @@ std::string type2name(const typet &type, const namespacet &ns)
   symbol_numbert symbol_number;
   return type2name(type, ns, symbol_number);
 }
+
+/// type2name generates strings that aren't valid C identifiers
+/// If we want utilities like dump_c to work properly identifiers
+/// should ideally always be valid C identifiers
+/// This replaces some invalid characters that can appear in type2name output.
+std::string type2identifier(const typet &type, const namespacet &ns)
+{
+  auto type2name_res = type2name(type, ns);
+  std::string result{};
+  for(char c : type2name_res)
+  {
+    switch(c)
+    {
+    case '*':
+      result += "_ptr_";
+      break;
+    case '{':
+      result += "_start_sub_";
+      break;
+    case '}':
+      result += "_end_sub_";
+      break;
+    default:
+      result += c;
+      break;
+    }
+  }
+  return result;
+}

src/ansi-c/type2name.h

@@ -20,4 +20,6 @@ class namespacet;
 
 std::string type2name(const typet &type, const namespacet &ns);
 
+std::string type2identifier(const typet &type, const namespacet &ns);
+
 #endif // CPROVER_ANSI_C_TYPE2NAME_H