Replace VEC (varobj_update_result) with std::vector

This patch replaces makes varobj_update return an std::vector, and
updates the fallouts.

To make that easier, the varobj_update_result is c++ified a bit.  I
added a constructor and initialized its fields in-class.  The newobj
vector is also made an std::vector, so that it's automatically freed
when varobj_update_result is destroyed and handled correctly by the
default move constructor.  I disabled copy constructor and assignment
for that structure, because normally it never needs to be copied, only
moved.

As a result, the newobj parameter of update_dynamic_varobj_children must
be changed to an std::vector.  The patch converts the other vector
parameters of update_dynamic_varobj_children to std::vector.  It's not
strictly necessary to do it in the same patch, but I think it makes
sense to do it.

gdb/ChangeLog:

	* varobj.h (struct varobj_update_result): Add constructor, add
	move constructor, disable copy and assign, initialize fields.
	<newobj>: Change type to std::vector.
	(varobj_update): Return std::vector.
	* varobj.c (install_dynamic_child): Change VEC parameters to
	std::vector and adjust.
	(update_dynamic_varobj_children): Likewise.
	(varobj_update): Return std::vector and adjust.
	* mi/mi-cmd-var.c (varobj_update_one): Adjust to vector changes.

4 files changed, 107 insertions, 129 deletions

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index d136e8d..1abef2b 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,5 +1,17 @@
 2017-11-22  Simon Marchi  <simon.marchi@polymtl.ca>
 
+	* varobj.h (struct varobj_update_result): Add constructor, add
+	move constructor, disable copy and assign, initialize fields.
+	<newobj>: Change type to std::vector.
+	(varobj_update): Return std::vector.
+	* varobj.c (install_dynamic_child): Change VEC parameters to
+	std::vector and adjust.
+	(update_dynamic_varobj_children): Likewise.
+	(varobj_update): Return std::vector and adjust.
+	* mi/mi-cmd-var.c (varobj_update_one): Adjust to vector changes.
+
+2017-11-22  Simon Marchi  <simon.marchi@polymtl.ca>
+
 	* varobj.h (struct varobj) <parent>: Remove const.
 	<children>: Change type to std::vector.
 	(varobj_list_children): Return std::vector const reference.
diff --git a/gdb/mi/mi-cmd-var.c b/gdb/mi/mi-cmd-var.c
index 084cc38..d051874 100644
--- a/gdb/mi/mi-cmd-var.c
+++ b/gdb/mi/mi-cmd-var.c
@@ -685,27 +685,24 @@ varobj_update_one (struct varobj *var, enum print_values print_values,
 		   int is_explicit)
 {
   struct ui_out *uiout = current_uiout;
-  VEC (varobj_update_result) *changes;
-  varobj_update_result *r;
-  int i;
-  
-  changes = varobj_update (&var, is_explicit);
+
+  std::vector<varobj_update_result> changes = varobj_update (&var, is_explicit);
   
-  for (i = 0; VEC_iterate (varobj_update_result, changes, i, r); ++i)
+  for (const varobj_update_result &r : changes)
     {
       int from, to;
 
       gdb::optional<ui_out_emit_tuple> tuple_emitter;
       if (mi_version (uiout) > 1)
 	tuple_emitter.emplace (uiout, nullptr);
-      uiout->field_string ("name", varobj_get_objname (r->varobj));
+      uiout->field_string ("name", varobj_get_objname (r.varobj));
 
-      switch (r->status)
+      switch (r.status)
 	{
 	case VAROBJ_IN_SCOPE:
-	  if (mi_print_value_p (r->varobj, print_values))
+	  if (mi_print_value_p (r.varobj, print_values))
 	    {
-	      std::string val = varobj_get_value (r->varobj);
+	      std::string val = varobj_get_value (r.varobj);
 
 	      uiout->field_string ("value", val.c_str ());
 	    }
@@ -719,53 +716,47 @@ varobj_update_one (struct varobj *var, enum print_values print_values,
  	  break;
 	}
 
-      if (r->status != VAROBJ_INVALID)
+      if (r.status != VAROBJ_INVALID)
 	{
-	  if (r->type_changed)
+	  if (r.type_changed)
 	    uiout->field_string ("type_changed", "true");
 	  else
 	    uiout->field_string ("type_changed", "false");
 	}
 
-      if (r->type_changed)
+      if (r.type_changed)
 	{
-	  std::string type_name = varobj_get_type (r->varobj);
+	  std::string type_name = varobj_get_type (r.varobj);
 
 	  uiout->field_string ("new_type", type_name.c_str ());
 	}
 
-      if (r->type_changed || r->children_changed)
+      if (r.type_changed || r.children_changed)
 	uiout->field_int ("new_num_children",
-			  varobj_get_num_children (r->varobj));
+			  varobj_get_num_children (r.varobj));
 
       gdb::unique_xmalloc_ptr<char> display_hint
-	= varobj_get_display_hint (r->varobj);
+	= varobj_get_display_hint (r.varobj);
       if (display_hint)
 	uiout->field_string ("displayhint", display_hint.get ());
 
-      if (varobj_is_dynamic_p (r->varobj))
+      if (varobj_is_dynamic_p (r.varobj))
 	uiout->field_int ("dynamic", 1);
 
-      varobj_get_child_range (r->varobj, &from, &to);
-      uiout->field_int ("has_more", varobj_has_more (r->varobj, to));
+      varobj_get_child_range (r.varobj, &from, &to);
+      uiout->field_int ("has_more", varobj_has_more (r.varobj, to));
 
-      if (r->newobj)
+      if (!r.newobj.empty ())
 	{
-	  int j;
-	  varobj_p child;
-
 	  ui_out_emit_list list_emitter (uiout, "new_children");
-	  for (j = 0; VEC_iterate (varobj_p, r->newobj, j, child); ++j)
+
+	  for (varobj *child : r.newobj)
 	    {
 	      ui_out_emit_tuple tuple_emitter (uiout, NULL);
 	      print_varobj (child, print_values, 1 /* print_expression */);
 	    }
-
-	  VEC_free (varobj_p, r->newobj);
-	  r->newobj = NULL;	/* Paranoia.  */
 	}
     }
-  VEC_free (varobj_update_result, changes);
 }
 
 void
diff --git a/gdb/varobj.c b/gdb/varobj.c
index 363ebec..29c338d 100644
--- a/gdb/varobj.c
+++ b/gdb/varobj.c
@@ -629,10 +629,10 @@ varobj_restrict_range (const std::vector<varobj *> &children,
 
 static void
 install_dynamic_child (struct varobj *var,
-		       VEC (varobj_p) **changed,
-		       VEC (varobj_p) **type_changed,
-		       VEC (varobj_p) **newobj,
-		       VEC (varobj_p) **unchanged,
+		       std::vector<varobj *> *changed,
+		       std::vector<varobj *> *type_changed,
+		       std::vector<varobj *> *newobj,
+		       std::vector<varobj *> *unchanged,
 		       int *cchanged,
 		       int index,
 		       struct varobj_item *item)
@@ -642,9 +642,9 @@ install_dynamic_child (struct varobj *var,
       /* There's no child yet.  */
       struct varobj *child = varobj_add_child (var, item);
 
-      if (newobj)
+      if (newobj != NULL)
 	{
-	  VEC_safe_push (varobj_p, *newobj, child);
+	  newobj->push_back (child);
 	  *cchanged = 1;
 	}
     }
@@ -655,16 +655,16 @@ install_dynamic_child (struct varobj *var,
 
       if (type_updated)
 	{
-	  if (type_changed)
-	    VEC_safe_push (varobj_p, *type_changed, existing);
+	  if (type_changed != NULL)
+	    type_changed->push_back (existing);
 	}
       if (install_new_value (existing, item->value, 0))
 	{
-	  if (!type_updated && changed)
-	    VEC_safe_push (varobj_p, *changed, existing);
+	  if (!type_updated && changed != NULL)
+	    changed->push_back (existing);
 	}
-      else if (!type_updated && unchanged)
-	VEC_safe_push (varobj_p, *unchanged, existing);
+      else if (!type_updated && unchanged != NULL)
+	unchanged->push_back (existing);
     }
 }
 
@@ -713,10 +713,10 @@ varobj_clear_saved_item (struct varobj_dynamic *var)
 
 static int
 update_dynamic_varobj_children (struct varobj *var,
-				VEC (varobj_p) **changed,
-				VEC (varobj_p) **type_changed,
-				VEC (varobj_p) **newobj,
-				VEC (varobj_p) **unchanged,
+				std::vector<varobj *> *changed,
+				std::vector<varobj *> *type_changed,
+				std::vector<varobj *> *newobj,
+				std::vector<varobj *> *unchanged,
 				int *cchanged,
 				int update_children,
 				int from,
@@ -1525,14 +1525,13 @@ varobj_value_has_mutated (const struct varobj *var, struct value *new_value,
    returns TYPE_CHANGED, then it has done this and VARP will be modified
    to point to the new varobj.  */
 
-VEC(varobj_update_result) *
+std::vector<varobj_update_result>
 varobj_update (struct varobj **varp, int is_explicit)
 {
   int type_changed = 0;
-  int i;
   struct value *newobj;
-  VEC (varobj_update_result) *stack = NULL;
-  VEC (varobj_update_result) *result = NULL;
+  std::vector<varobj_update_result> stack;
+  std::vector<varobj_update_result> result;
 
   /* Frozen means frozen -- we don't check for any change in
      this varobj, including its going out of scope, or
@@ -1544,20 +1543,13 @@ varobj_update (struct varobj **varp, int is_explicit)
 
   if (!(*varp)->root->is_valid)
     {
-      varobj_update_result r = {0};
-
-      r.varobj = *varp;
-      r.status = VAROBJ_INVALID;
-      VEC_safe_push (varobj_update_result, result, &r);
+      result.emplace_back (*varp, VAROBJ_INVALID);
       return result;
     }
 
   if ((*varp)->root->rootvar == *varp)
     {
-      varobj_update_result r = {0};
-
-      r.varobj = *varp;
-      r.status = VAROBJ_IN_SCOPE;
+      varobj_update_result r (*varp);
 
       /* Update the root variable.  value_of_root can return NULL
 	 if the variable is no longer around, i.e. we stepped out of
@@ -1579,28 +1571,23 @@ varobj_update (struct varobj **varp, int is_explicit)
       if (r.status == VAROBJ_NOT_IN_SCOPE)
 	{
 	  if (r.type_changed || r.changed)
-	    VEC_safe_push (varobj_update_result, result, &r);
+	    result.push_back (std::move (r));
+
 	  return result;
 	}
-            
-      VEC_safe_push (varobj_update_result, stack, &r);
-    }
-  else
-    {
-      varobj_update_result r = {0};
 
-      r.varobj = *varp;
-      VEC_safe_push (varobj_update_result, stack, &r);
+      stack.push_back (std::move (r));
     }
+  else
+    stack.emplace_back (*varp);
 
   /* Walk through the children, reconstructing them all.  */
-  while (!VEC_empty (varobj_update_result, stack))
+  while (!stack.empty ())
     {
-      varobj_update_result r = *(VEC_last (varobj_update_result, stack));
+      varobj_update_result r = std::move (stack.back ());
+      stack.pop_back ();
       struct varobj *v = r.varobj;
 
-      VEC_pop (varobj_update_result, stack);
-
       /* Update this variable, unless it's a root, which is already
 	 updated.  */
       if (!r.value_installed)
@@ -1638,9 +1625,8 @@ varobj_update (struct varobj **varp, int is_explicit)
 	 for which -var-list-children was never invoked.  */
       if (varobj_is_dynamic_p (v))
 	{
-	  VEC (varobj_p) *changed = 0, *type_changed = 0, *unchanged = 0;
-	  VEC (varobj_p) *newobj = 0;
-	  int i, children_changed = 0;
+	  std::vector<varobj *> changed, type_changed, unchanged, newobj;
+	  int children_changed = 0;
 
 	  if (v->frozen)
 	    continue;
@@ -1664,7 +1650,7 @@ varobj_update (struct varobj **varp, int is_explicit)
 		}
 
 	      if (r.changed)
-		VEC_safe_push (varobj_update_result, result, &r);
+		result.push_back (std::move (r));
 
 	      continue;
 	    }
@@ -1675,58 +1661,48 @@ varobj_update (struct varobj **varp, int is_explicit)
 					      &unchanged, &children_changed, 1,
 					      v->from, v->to))
 	    {
-	      if (children_changed || newobj)
+	      if (children_changed || !newobj.empty ())
 		{
 		  r.children_changed = 1;
-		  r.newobj = newobj;
+		  r.newobj = std::move (newobj);
 		}
 	      /* Push in reverse order so that the first child is
 		 popped from the work stack first, and so will be
 		 added to result first.  This does not affect
 		 correctness, just "nicer".  */
-	      for (i = VEC_length (varobj_p, type_changed) - 1; i >= 0; --i)
+	      for (int i = type_changed.size () - 1; i >= 0; --i)
 		{
-		  varobj_p tmp = VEC_index (varobj_p, type_changed, i);
-		  varobj_update_result r = {0};
+		  varobj_update_result r (type_changed[i]);
 
 		  /* Type may change only if value was changed.  */
-		  r.varobj = tmp;
 		  r.changed = 1;
 		  r.type_changed = 1;
 		  r.value_installed = 1;
-		  VEC_safe_push (varobj_update_result, stack, &r);
+
+		  stack.push_back (std::move (r));
 		}
-	      for (i = VEC_length (varobj_p, changed) - 1; i >= 0; --i)
+	      for (int i = changed.size () - 1; i >= 0; --i)
 		{
-		  varobj_p tmp = VEC_index (varobj_p, changed, i);
-		  varobj_update_result r = {0};
+		  varobj_update_result r (changed[i]);
 
-		  r.varobj = tmp;
 		  r.changed = 1;
 		  r.value_installed = 1;
-		  VEC_safe_push (varobj_update_result, stack, &r);
+
+		  stack.push_back (std::move (r));
 		}
-	      for (i = VEC_length (varobj_p, unchanged) - 1; i >= 0; --i)
-	      	{
-		  varobj_p tmp = VEC_index (varobj_p, unchanged, i);
-
-	      	  if (!tmp->frozen)
-	      	    {
-	      	      varobj_update_result r = {0};
-
-		      r.varobj = tmp;
-	      	      r.value_installed = 1;
-	      	      VEC_safe_push (varobj_update_result, stack, &r);
-	      	    }
-	      	}
-	      if (r.changed || r.children_changed)
-		VEC_safe_push (varobj_update_result, result, &r);
+	      for (int i = unchanged.size () - 1; i >= 0; --i)
+		{
+		  if (!unchanged[i]->frozen)
+		    {
+		      varobj_update_result r (unchanged[i]);
 
-	      /* Free CHANGED, TYPE_CHANGED and UNCHANGED, but not NEW,
-		 because NEW has been put into the result vector.  */
-	      VEC_free (varobj_p, changed);
-	      VEC_free (varobj_p, type_changed);
-	      VEC_free (varobj_p, unchanged);
+		      r.value_installed = 1;
+
+		      stack.push_back (std::move (r));
+		    }
+		}
+	      if (r.changed || r.children_changed)
+		result.push_back (std::move (r));
 
 	      continue;
 	    }
@@ -1736,29 +1712,21 @@ varobj_update (struct varobj **varp, int is_explicit)
 	 child is popped from the work stack first, and so
 	 will be added to result first.  This does not
 	 affect correctness, just "nicer".  */
-      for (i = v->children.size () - 1; i >= 0; --i)
+      for (int i = v->children.size () - 1; i >= 0; --i)
 	{
 	  varobj *c = v->children[i];
 
 	  /* Child may be NULL if explicitly deleted by -var-delete.  */
 	  if (c != NULL && !c->frozen)
-	    {
-	      varobj_update_result r = {0};
-
-	      r.varobj = c;
-	      VEC_safe_push (varobj_update_result, stack, &r);
-	    }
+	    stack.emplace_back (c);
 	}
 
       if (r.changed || r.type_changed)
-	VEC_safe_push (varobj_update_result, result, &r);
+	result.push_back (std::move (r));
     }
 
-  VEC_free (varobj_update_result, stack);
-
   return result;
 }
-
 
 /* Helper functions */
 
diff --git a/gdb/varobj.h b/gdb/varobj.h
index ec8d62c..f8738f5 100644
--- a/gdb/varobj.h
+++ b/gdb/varobj.h
@@ -60,26 +60,33 @@ struct varobj;
 typedef struct varobj *varobj_p;
 DEF_VEC_P (varobj_p);
 
-typedef struct varobj_update_result_t
+struct varobj_update_result
 {
+  varobj_update_result (struct varobj *varobj_,
+			varobj_scope_status status_ = VAROBJ_IN_SCOPE)
+  : varobj (varobj_), status (status_)
+  {}
+
+  varobj_update_result (varobj_update_result &&other) = default;
+
+  DISABLE_COPY_AND_ASSIGN (varobj_update_result);
+
   struct varobj *varobj;
-  int type_changed;
-  int children_changed;
-  int changed;
+  int type_changed = 0;
+  int children_changed = 0;
+  int changed = 0;
   enum varobj_scope_status status;
   /* This variable is used internally by varobj_update to indicate if the
      new value of varobj is already computed and installed, or has to
      be yet installed.  Don't use this outside varobj.c.  */
-  int value_installed;  
+  int value_installed = 0;
 
   /* This will be non-NULL when new children were added to the varobj.
      It lists the new children (which must necessarily come at the end
      of the child list) added during an update.  The caller is
      responsible for freeing this vector.  */
-  VEC (varobj_p) *newobj;
-} varobj_update_result;
-
-DEF_VEC_O (varobj_update_result);
+  std::vector<struct varobj *> newobj;
+};
 
 struct varobj_root;
 struct varobj_dynamic;
@@ -305,8 +312,8 @@ extern int varobj_set_value (struct varobj *var, const char *expression);
 extern void all_root_varobjs (void (*func) (struct varobj *var, void *data),
 			      void *data);
 
-extern VEC(varobj_update_result) *varobj_update (struct varobj **varp, 
-						 int is_explicit);
+extern std::vector<varobj_update_result>
+  varobj_update (struct varobj **varp, int is_explicit);
 
 extern void varobj_invalidate (void);