Use unique_xmalloc_ptr<char> when demangling

I noticed that some methods in language_defn could use
unique_xmalloc_ptr<char> rather than a plain 'char *'.  This patch
implements this change, fixing up the fallout and changing
gdb_demangle to also return this type.  In one spot, std::string is
used to simplify some related code, and in another, an auto_obstack is
used to avoid manual management.

Regression tested on x86-64 Fedora 34.

1 files changed, 12 insertions, 17 deletions

diff --git a/gdb/cp-support.c b/gdb/cp-support.c
index fb4c836..367fb6a 100644
--- a/gdb/cp-support.c
+++ b/gdb/cp-support.c
@@ -661,10 +661,9 @@ cp_canonicalize_string (const char *string)
 
 static std::unique_ptr<demangle_parse_info>
 mangled_name_to_comp (const char *mangled_name, int options,
-		      void **memory, char **demangled_p)
+		      void **memory,
+		      gdb::unique_xmalloc_ptr<char> *demangled_p)
 {
-  char *demangled_name;
-
   /* If it looks like a v3 mangled name, then try to go directly
      to trees.  */
   if (mangled_name[0] == '_' && mangled_name[1] == 'Z')
@@ -684,22 +683,20 @@ mangled_name_to_comp (const char *mangled_name, int options,
 
   /* If it doesn't, or if that failed, then try to demangle the
      name.  */
-  demangled_name = gdb_demangle (mangled_name, options);
+  gdb::unique_xmalloc_ptr<char> demangled_name = gdb_demangle (mangled_name,
+							       options);
   if (demangled_name == NULL)
    return NULL;
   
   /* If we could demangle the name, parse it to build the component
      tree.  */
   std::unique_ptr<demangle_parse_info> info
-    = cp_demangled_name_to_comp (demangled_name, NULL);
+    = cp_demangled_name_to_comp (demangled_name.get (), NULL);
 
   if (info == NULL)
-    {
-      xfree (demangled_name);
-      return NULL;
-    }
+    return NULL;
 
-  *demangled_p = demangled_name;
+  *demangled_p = std::move (demangled_name);
   return info;
 }
 
@@ -709,7 +706,7 @@ char *
 cp_class_name_from_physname (const char *physname)
 {
   void *storage = NULL;
-  char *demangled_name = NULL;
+  gdb::unique_xmalloc_ptr<char> demangled_name;
   gdb::unique_xmalloc_ptr<char> ret;
   struct demangle_component *ret_comp, *prev_comp, *cur_comp;
   std::unique_ptr<demangle_parse_info> info;
@@ -789,7 +786,6 @@ cp_class_name_from_physname (const char *physname)
     }
 
   xfree (storage);
-  xfree (demangled_name);
   return ret.release ();
 }
 
@@ -857,7 +853,7 @@ char *
 method_name_from_physname (const char *physname)
 {
   void *storage = NULL;
-  char *demangled_name = NULL;
+  gdb::unique_xmalloc_ptr<char> demangled_name;
   gdb::unique_xmalloc_ptr<char> ret;
   struct demangle_component *ret_comp;
   std::unique_ptr<demangle_parse_info> info;
@@ -875,7 +871,6 @@ method_name_from_physname (const char *physname)
     ret = cp_comp_to_string (ret_comp, 10);
 
   xfree (storage);
-  xfree (demangled_name);
   return ret.release ();
 }
 
@@ -1604,10 +1599,10 @@ report_failed_demangle (const char *name, bool core_dump_allowed,
 
 /* A wrapper for bfd_demangle.  */
 
-char *
+gdb::unique_xmalloc_ptr<char>
 gdb_demangle (const char *name, int options)
 {
-  char *result = NULL;
+  gdb::unique_xmalloc_ptr<char> result;
   int crash_signal = 0;
 
 #ifdef HAVE_WORKING_FORK
@@ -1636,7 +1631,7 @@ gdb_demangle (const char *name, int options)
 #endif
 
   if (crash_signal == 0)
-    result = bfd_demangle (NULL, name, options);
+    result.reset (bfd_demangle (NULL, name, options));
 
 #ifdef HAVE_WORKING_FORK
   if (catch_demangler_crashes)