[PATCH] Return std::string from ada_encode

[Tom Tromey <tromey@adacore.com>]

This changes ada_encode to return a std::string.  This simplifies it
somewhat, removes a use of GROW_VECT, and is also simpler for callers
to use.

gdb/ChangeLog
2020-10-08  Tom Tromey  <tromey@adacore.com>

	* ada-lang.h (ada_encode): Return std::string.
	* ada-lang.c (ada_encode_1): Return std::string.
	(ada_encode): Likewise.
	(type_from_tag, ada_lookup_name_info::ada_lookup_name_info):
	Update.
	* ada-exp.y (block_lookup, write_var_or_type): Update.
---
 gdb/ChangeLog  |  9 +++++++++
 gdb/ada-exp.y  | 13 +++++++++----
 gdb/ada-lang.c | 50 +++++++++++++++-----------------------------------
 gdb/ada-lang.h |  2 +-
 4 files changed, 34 insertions(+), 40 deletions(-)

diff --git a/gdb/ada-exp.y b/gdb/ada-exp.y
index 57d89b01fec..d09b43ea9ca 100644
--- a/gdb/ada-exp.y
+++ b/gdb/ada-exp.y
@@ -953,13 +953,17 @@ block_lookup (const struct block *context, const char *raw_name)
   struct symtab *symtab;
   const struct block *result = NULL;
 
+  std::string name_storage;
   if (raw_name[0] == '\'')
     {
       raw_name += 1;
       name = raw_name;
     }
   else
-    name = ada_encode (raw_name);
+    {
+      name_storage = ada_encode (raw_name);
+      name = name_storage.c_str ();
+    }
 
   nsyms = ada_lookup_symbol_list (name, context, VAR_DOMAIN, &syms);
 
@@ -1201,9 +1205,10 @@ write_var_or_type (struct parser_state *par_state,
   if (block == NULL)
     block = par_state->expression_context_block;
 
-  encoded_name = ada_encode (name0.ptr);
-  name_len = strlen (encoded_name);
-  encoded_name = obstack_strndup (&temp_parse_space, encoded_name, name_len);
+  std::string name_storage = ada_encode (name0.ptr);
+  name_len = name_storage.size ();
+  encoded_name = obstack_strndup (&temp_parse_space, name_storage.c_str (),
+				  name_len);
   for (depth = 0; depth < MAX_RENAMING_CHAIN_LENGTH; depth += 1)
     {
       int tail_index;
diff --git a/gdb/ada-lang.c b/gdb/ada-lang.c
index 0df406bff48..fbce14bbe42 100644
--- a/gdb/ada-lang.c
+++ b/gdb/ada-lang.c
@@ -918,33 +918,21 @@ const struct ada_opname_map ada_opname_table[] = {
   {NULL, NULL}
 };
 
-/* The "encoded" form of DECODED, according to GNAT conventions.  The
-   result is valid until the next call to ada_encode.  If
+/* The "encoded" form of DECODED, according to GNAT conventions.  If
    THROW_ERRORS, throw an error if invalid operator name is found.
-   Otherwise, return NULL in that case.  */
+   Otherwise, return the empty string in that case.  */
 
-static char *
+static std::string
 ada_encode_1 (const char *decoded, bool throw_errors)
 {
-  static char *encoding_buffer = NULL;
-  static size_t encoding_buffer_size = 0;
-  const char *p;
-  int k;
-
   if (decoded == NULL)
-    return NULL;
-
-  GROW_VECT (encoding_buffer, encoding_buffer_size,
-             2 * strlen (decoded) + 10);
+    return {};
 
-  k = 0;
-  for (p = decoded; *p != '\0'; p += 1)
+  std::string encoding_buffer;
+  for (const char *p = decoded; *p != '\0'; p += 1)
     {
       if (*p == '.')
-        {
-          encoding_buffer[k] = encoding_buffer[k + 1] = '_';
-          k += 2;
-        }
+	encoding_buffer.append ("__");
       else if (*p == '"')
         {
           const struct ada_opname_map *mapping;
@@ -958,27 +946,21 @@ ada_encode_1 (const char *decoded, bool throw_errors)
 	      if (throw_errors)
 		error (_("invalid Ada operator name: %s"), p);
 	      else
-		return NULL;
+		return {};
 	    }
-          strcpy (encoding_buffer + k, mapping->encoded);
-          k += strlen (mapping->encoded);
+	  encoding_buffer.append (mapping->encoded);
           break;
         }
       else
-        {
-          encoding_buffer[k] = *p;
-          k += 1;
-        }
+	encoding_buffer.push_back (*p);
     }
 
-  encoding_buffer[k] = '\0';
   return encoding_buffer;
 }
 
-/* The "encoded" form of DECODED, according to GNAT conventions.
-   The result is valid until the next call to ada_encode.  */
+/* The "encoded" form of DECODED, according to GNAT conventions.  */
 
-char *
+std::string
 ada_encode (const char *decoded)
 {
   return ada_encode_1 (decoded, true);
@@ -6384,7 +6366,7 @@ type_from_tag (struct value *tag)
   gdb::unique_xmalloc_ptr<char> type_name = ada_tag_name (tag);
 
   if (type_name != NULL)
-    return ada_find_any_type (ada_encode (type_name.get ()));
+    return ada_find_any_type (ada_encode (type_name.get ()).c_str ());
   return NULL;
 }
 
@@ -13613,10 +13595,8 @@ ada_lookup_name_info::ada_lookup_name_info (const lookup_name_info &lookup_name)
       if (!m_encoded_p)
 	{
 	  const char *folded = ada_fold_name (user_name);
-	  const char *encoded = ada_encode_1 (folded, false);
-	  if (encoded != NULL)
-	    m_encoded_name = encoded;
-	  else
+	  m_encoded_name = ada_encode_1 (folded, false);
+	  if (m_encoded_name.empty ())
 	    m_encoded_name = gdb::to_string (user_name);
 	}
       else
diff --git a/gdb/ada-lang.h b/gdb/ada-lang.h
index ae313ce700a..93319267654 100644
--- a/gdb/ada-lang.h
+++ b/gdb/ada-lang.h
@@ -318,7 +318,7 @@ extern struct type *ada_get_base_type (struct type *);
 
 extern struct type *ada_check_typedef (struct type *);
 
-extern char *ada_encode (const char *);
+extern std::string ada_encode (const char *);
 
 extern const char *ada_enum_name (const char *);
 
-- 
2.26.2