[PATCH 1/3] gdb: store internalvars in an std::vector

[Simon Marchi <simon.marchi@efficios.com>]

Change the storage of internalvars to an std::vector of unique pointers
to internalval.  This helps automate memory management, and will help
keep internalvars sorted in a subsequent patch.

I initially tried to use an std::vector<internalval> initially, but some
parts of the code need for the addresses of internalvars to be stable.

Change-Id: I1fca7e7877cc984a3a3432c7639d45e68d437241
---
 gdb/value.c | 32 +++++++++++++-------------------
 1 file changed, 13 insertions(+), 19 deletions(-)

diff --git a/gdb/value.c b/gdb/value.c
index 7873aeb9558e..e884913abe5a 100644
--- a/gdb/value.c
+++ b/gdb/value.c
@@ -1829,7 +1829,6 @@ union internalvar_data
 
 struct internalvar
 {
-  struct internalvar *next;
   char *name;
 
   /* We support various different kinds of content of an internal variable.
@@ -1841,7 +1840,9 @@ struct internalvar
   union internalvar_data u;
 };
 
-static struct internalvar *internalvars;
+using internalvar_up = std::unique_ptr<internalvar>;
+
+static std::vector<internalvar_up> internalvars;
 
 /* If the variable does not already exist create it and give it the
    value given.  If no value is given then the default is zero.  */
@@ -1891,11 +1892,9 @@ init_if_undefined_command (const char* args, int from_tty)
 struct internalvar *
 lookup_only_internalvar (const char *name)
 {
-  struct internalvar *var;
-
-  for (var = internalvars; var; var = var->next)
+  for (internalvar_up &var : internalvars)
     if (strcmp (var->name, name) == 0)
-      return var;
+      return var.get ();
 
   return NULL;
 }
@@ -1906,12 +1905,11 @@ lookup_only_internalvar (const char *name)
 void
 complete_internalvar (completion_tracker &tracker, const char *name)
 {
-  struct internalvar *var;
   int len;
 
   len = strlen (name);
 
-  for (var = internalvars; var; var = var->next)
+  for (internalvar_up &var : internalvars)
     if (strncmp (var->name, name, len) == 0)
       tracker.add_completion (make_unique_xstrdup (var->name));
 }
@@ -1922,12 +1920,12 @@ complete_internalvar (completion_tracker &tracker, const char *name)
 struct internalvar *
 create_internalvar (const char *name)
 {
-  struct internalvar *var = XNEW (struct internalvar);
+  internalvars.emplace_back (new internalvar);
+  internalvar *var = internalvars.back ().get ();
 
   var->name = xstrdup (name);
   var->kind = INTERNALVAR_VOID;
-  var->next = internalvars;
-  internalvars = var;
+
   return var;
 }
 
@@ -2412,8 +2410,6 @@ preserve_one_varobj (struct varobj *varobj, struct objfile *objfile,
 void
 preserve_values (struct objfile *objfile)
 {
-  struct internalvar *var;
-
   /* Create the hash table.  We allocate on the objfile's obstack, since
      it is soon to be deleted.  */
   htab_up copied_types = create_copied_types_hash ();
@@ -2421,8 +2417,8 @@ preserve_values (struct objfile *objfile)
   for (const value_ref_ptr &item : value_history)
     item->preserve (objfile, copied_types.get ());
 
-  for (var = internalvars; var; var = var->next)
-    preserve_one_internalvar (var, objfile, copied_types.get ());
+  for (internalvar_up &var : internalvars)
+    preserve_one_internalvar (var.get (), objfile, copied_types.get ());
 
   /* For the remaining varobj, check that none has type owned by OBJFILE.  */
   all_root_varobjs ([&copied_types, objfile] (struct varobj *varobj)
@@ -2438,14 +2434,12 @@ static void
 show_convenience (const char *ignore, int from_tty)
 {
   struct gdbarch *gdbarch = get_current_arch ();
-  struct internalvar *var;
   int varseen = 0;
   struct value_print_options opts;
 
   get_user_print_options (&opts);
-  for (var = internalvars; var; var = var->next)
+  for (internalvar_up &var : internalvars)
     {
-
       if (!varseen)
 	{
 	  varseen = 1;
@@ -2456,7 +2450,7 @@ show_convenience (const char *ignore, int from_tty)
 	{
 	  struct value *val;
 
-	  val = value_of_internalvar (gdbarch, var);
+	  val = value_of_internalvar (gdbarch, var.get ());
 	  value_print (val, gdb_stdout, &opts);
 	}
       catch (const gdb_exception_error &ex)
-- 
2.39.1