Finish constification of varobj interface

This completes the constification of the struct varobj pointers in the
lang_varobj_ops interface partially done in
b09e2c591f9221d865bfe8425990a6bf9fab24e3. As suggested by Pedro,
varobj_get_path_expr casts away the const to assign the "mutable" struct
member.

gdb/ChangeLog:

	* ada-varobj.c (ada_name_of_child): Constify parent.
	(ada_path_expr_of_child): Same.
	(ada_value_of_child): Same.
	(ada_type_of_child): Same.
	* c-varobj.c (c_is_path_expr_parent): Same.
	(c_describe_child): Same.
	(c_name_of_child): Same.
	(c_value_of_child): Same.
	(c_type_of_child): Same.
	(cplus_number_of_children): Same.
	(cplus_describe_child): Constify var.
	(cplus_name_of_child): Constify parent.
	(cplus_value_of_child): Same.
	(cplus_type_of_child): Same.
	* jv-varobj.c (java_name_of_child): Same.
	(java_value_of_child): Same.
	(java_type_of_child): Same.
	* varobj.c (value_of_child): Same.
	(varobj_default_is_path_expr_parent): Constify var, parent and return
	value.
	(varobj_get_path_expr): Constify var, modify path_expr through
	mutable_var.
	(install_new_value): Constify parent.
	(value_of_child): Constify parent.
	* varobj.h (struct varobj): Constify parent.
	(struct lang_varobj_ops): Constify name_of_child, value_of_child and
	type_of_child.
	(varobj_get_path_expr): Constify var.
	(varobj_get_path_expr_parent): Constify var and return value.

6 files changed, 66 insertions, 32 deletions

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 9941dba..6b9adf0 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,35 @@
+2015-02-10  Simon Marchi  <simon.marchi@ericsson.com>
+
+	* ada-varobj.c (ada_name_of_child): Constify parent.
+	(ada_path_expr_of_child): Same.
+	(ada_value_of_child): Same.
+	(ada_type_of_child): Same.
+	* c-varobj.c (c_is_path_expr_parent): Same.
+	(c_describe_child): Same.
+	(c_name_of_child): Same.
+	(c_value_of_child): Same.
+	(c_type_of_child): Same.
+	(cplus_number_of_children): Same.
+	(cplus_describe_child): Constify var.
+	(cplus_name_of_child): Constify parent.
+	(cplus_value_of_child): Same.
+	(cplus_type_of_child): Same.
+	* jv-varobj.c (java_name_of_child): Same.
+	(java_value_of_child): Same.
+	(java_type_of_child): Same.
+	* varobj.c (value_of_child): Same.
+	(varobj_default_is_path_expr_parent): Constify var, parent and return
+	value.
+	(varobj_get_path_expr): Constify var, modify path_expr through
+	mutable_var.
+	(install_new_value): Constify parent.
+	(value_of_child): Constify parent.
+	* varobj.h (struct varobj): Constify parent.
+	(struct lang_varobj_ops): Constify name_of_child, value_of_child and
+	type_of_child.
+	(varobj_get_path_expr): Constify var.
+	(varobj_get_path_expr_parent): Constify var and return value.
+
 2015-02-10  Luis Machado  <lgustavo@codesourcery.com>
 
 	* arm-tdep.c (arm_prologue_unwind_stop_reason): New function.
diff --git a/gdb/ada-varobj.c b/gdb/ada-varobj.c
index 7407af4..83d0707 100644
--- a/gdb/ada-varobj.c
+++ b/gdb/ada-varobj.c
@@ -918,7 +918,7 @@ ada_name_of_variable (const struct varobj *parent)
 }
 
 static char *
-ada_name_of_child (struct varobj *parent, int index)
+ada_name_of_child (const struct varobj *parent, int index)
 {
   return ada_varobj_get_name_of_child (parent->value, parent->type,
 				       parent->name, index);
@@ -927,7 +927,7 @@ ada_name_of_child (struct varobj *parent, int index)
 static char*
 ada_path_expr_of_child (const struct varobj *child)
 {
-  struct varobj *parent = child->parent;
+  const struct varobj *parent = child->parent;
   const char *parent_path_expr = varobj_get_path_expr (parent);
 
   return ada_varobj_get_path_expr_of_child (parent->value,
@@ -938,14 +938,14 @@ ada_path_expr_of_child (const struct varobj *child)
 }
 
 static struct value *
-ada_value_of_child (struct varobj *parent, int index)
+ada_value_of_child (const struct varobj *parent, int index)
 {
   return ada_varobj_get_value_of_child (parent->value, parent->type,
 					parent->name, index);
 }
 
 static struct type *
-ada_type_of_child (struct varobj *parent, int index)
+ada_type_of_child (const struct varobj *parent, int index)
 {
   return ada_varobj_get_type_of_child (parent->value, parent->type,
 				       index);
diff --git a/gdb/c-varobj.c b/gdb/c-varobj.c
index 9394d7c..363a356 100644
--- a/gdb/c-varobj.c
+++ b/gdb/c-varobj.c
@@ -146,7 +146,7 @@ c_is_path_expr_parent (const struct varobj *var)
       && TYPE_NAME (type) == NULL
       && TYPE_TAG_NAME (type) == NULL)
     {
-      struct varobj *parent = var->parent;
+      const struct varobj *parent = var->parent;
 
       while (parent != NULL && CPLUS_FAKE_CHILD (parent))
 	parent = parent->parent;
@@ -282,7 +282,7 @@ value_struct_element_index (struct value *value, int type_index)
    to NULL.  */
 
 static void 
-c_describe_child (struct varobj *parent, int index,
+c_describe_child (const struct varobj *parent, int index,
 		  char **cname, struct value **cvalue, struct type **ctype,
 		  char **cfull_expression)
 {
@@ -422,7 +422,7 @@ c_describe_child (struct varobj *parent, int index,
 }
 
 static char *
-c_name_of_child (struct varobj *parent, int index)
+c_name_of_child (const struct varobj *parent, int index)
 {
   char *name;
 
@@ -441,7 +441,7 @@ c_path_expr_of_child (const struct varobj *child)
 }
 
 static struct value *
-c_value_of_child (struct varobj *parent, int index)
+c_value_of_child (const struct varobj *parent, int index)
 {
   struct value *value = NULL;
 
@@ -450,7 +450,7 @@ c_value_of_child (struct varobj *parent, int index)
 }
 
 static struct type *
-c_type_of_child (struct varobj *parent, int index)
+c_type_of_child (const struct varobj *parent, int index)
 {
   struct type *type = NULL;
 
@@ -614,7 +614,7 @@ cplus_number_of_children (const struct varobj *var)
       /* It is necessary to access a real type (via RTTI).  */
       if (opts.objectprint)
         {
-	  struct varobj *parent = var->parent;
+	  const struct varobj *parent = var->parent;
 
 	  value = parent->value;
 	  lookup_actual_type = (TYPE_CODE (parent->type) == TYPE_CODE_REF
@@ -697,7 +697,7 @@ match_accessibility (struct type *type, int index, enum accessibility acc)
 }
 
 static void
-cplus_describe_child (struct varobj *parent, int index,
+cplus_describe_child (const struct varobj *parent, int index,
 		      char **cname, struct value **cvalue, struct type **ctype,
 		      char **cfull_expression)
 {
@@ -706,7 +706,7 @@ cplus_describe_child (struct varobj *parent, int index,
   int was_ptr;
   int lookup_actual_type = 0;
   char *parent_expression = NULL;
-  struct varobj *var;
+  const struct varobj *var;
   struct value_print_options opts;
 
   if (cname)
@@ -898,7 +898,7 @@ cplus_describe_child (struct varobj *parent, int index,
 }
 
 static char *
-cplus_name_of_child (struct varobj *parent, int index)
+cplus_name_of_child (const struct varobj *parent, int index)
 {
   char *name = NULL;
 
@@ -917,7 +917,7 @@ cplus_path_expr_of_child (const struct varobj *child)
 }
 
 static struct value *
-cplus_value_of_child (struct varobj *parent, int index)
+cplus_value_of_child (const struct varobj *parent, int index)
 {
   struct value *value = NULL;
 
@@ -926,7 +926,7 @@ cplus_value_of_child (struct varobj *parent, int index)
 }
 
 static struct type *
-cplus_type_of_child (struct varobj *parent, int index)
+cplus_type_of_child (const struct varobj *parent, int index)
 {
   struct type *type = NULL;
 
diff --git a/gdb/jv-varobj.c b/gdb/jv-varobj.c
index dbd92a6..69e88fb 100644
--- a/gdb/jv-varobj.c
+++ b/gdb/jv-varobj.c
@@ -47,7 +47,7 @@ java_name_of_variable (const struct varobj *parent)
 }
 
 static char *
-java_name_of_child (struct varobj *parent, int index)
+java_name_of_child (const struct varobj *parent, int index)
 {
   char *name, *p;
 
@@ -72,13 +72,13 @@ java_path_expr_of_child (const struct varobj *child)
 }
 
 static struct value *
-java_value_of_child (struct varobj *parent, int index)
+java_value_of_child (const struct varobj *parent, int index)
 {
   return cplus_varobj_ops.value_of_child (parent, index);
 }
 
 static struct type *
-java_type_of_child (struct varobj *parent, int index)
+java_type_of_child (const struct varobj *parent, int index)
 {
   return cplus_varobj_ops.type_of_child (parent, index);
 }
diff --git a/gdb/varobj.c b/gdb/varobj.c
index 268ba3c..43ea96f 100644
--- a/gdb/varobj.c
+++ b/gdb/varobj.c
@@ -201,7 +201,7 @@ static char *name_of_child (struct varobj *, int);
 
 static struct value *value_of_root (struct varobj **var_handle, int *);
 
-static struct value *value_of_child (struct varobj *parent, int index);
+static struct value *value_of_child (const struct varobj *parent, int index);
 
 static char *my_value_of_variable (struct varobj *var,
 				   enum varobj_display_formats format);
@@ -1019,10 +1019,10 @@ varobj_default_is_path_expr_parent (const struct varobj *var)
 
 /* Return the path expression parent for VAR.  */
 
-struct varobj *
-varobj_get_path_expr_parent (struct varobj *var)
+const struct varobj *
+varobj_get_path_expr_parent (const struct varobj *var)
 {
-  struct varobj *parent = var;
+  const struct varobj *parent = var;
 
   while (!is_root_p (parent) && !is_path_expr_parent (parent))
     parent = parent->parent;
@@ -1033,16 +1033,17 @@ varobj_get_path_expr_parent (struct varobj *var)
 /* Return a pointer to the full rooted expression of varobj VAR.
    If it has not been computed yet, compute it.  */
 char *
-varobj_get_path_expr (struct varobj *var)
+varobj_get_path_expr (const struct varobj *var)
 {
   if (var->path_expr == NULL)
     {
       /* For root varobjs, we initialize path_expr
 	 when creating varobj, so here it should be
 	 child varobj.  */
+      struct varobj *mutable_var = (struct varobj *) var;
       gdb_assert (!is_root_p (var));
 
-      var->path_expr = (*var->root->lang_ops->path_expr_of_child) (var);
+      mutable_var->path_expr = (*var->root->lang_ops->path_expr_of_child) (var);
     }
 
   return var->path_expr;
@@ -1378,7 +1379,7 @@ install_new_value (struct varobj *var, struct value *value, int initial)
      will be lazy, which means we've lost that old value.  */
   if (need_to_fetch && value && value_lazy (value))
     {
-      struct varobj *parent = var->parent;
+      const struct varobj *parent = var->parent;
       int frozen = var->frozen;
 
       for (; !frozen && parent; parent = parent->parent)
@@ -2483,7 +2484,7 @@ value_of_root (struct varobj **var_handle, int *type_changed)
 
 /* What is the ``struct value *'' for the INDEX'th child of PARENT?  */
 static struct value *
-value_of_child (struct varobj *parent, int index)
+value_of_child (const struct varobj *parent, int index)
 {
   struct value *value;
 
diff --git a/gdb/varobj.h b/gdb/varobj.h
index 30c31ef..6fe7009 100644
--- a/gdb/varobj.h
+++ b/gdb/varobj.h
@@ -120,7 +120,7 @@ struct varobj
   int num_children;
 
   /* If this object is a child, this points to its immediate parent.  */
-  struct varobj *parent;
+  const struct varobj *parent;
 
   /* Children of this object.  */
   VEC (varobj_p) *children;
@@ -175,7 +175,7 @@ struct lang_varobj_ops
 
   /* The name of the INDEX'th child of PARENT.  The returned value must be
      freed by the caller.  */
-  char *(*name_of_child) (struct varobj *parent, int index);
+  char *(*name_of_child) (const struct varobj *parent, int index);
 
   /* Returns the rooted expression of CHILD, which is a variable
      obtain that has some parent.  The returned value must be freed by the
@@ -183,10 +183,10 @@ struct lang_varobj_ops
   char *(*path_expr_of_child) (const struct varobj *child);
 
   /* The ``struct value *'' of the INDEX'th child of PARENT.  */
-  struct value *(*value_of_child) (struct varobj *parent, int index);
+  struct value *(*value_of_child) (const struct varobj *parent, int index);
 
   /* The type of the INDEX'th child of PARENT.  */
-  struct type *(*type_of_child) (struct varobj *parent, int index);
+  struct type *(*type_of_child) (const struct varobj *parent, int index);
 
   /* The current value of VAR.  The returned value must be freed by the
      caller.  */
@@ -285,7 +285,7 @@ extern char *varobj_get_type (struct varobj *var);
 
 extern struct type *varobj_get_gdb_type (const struct varobj *var);
 
-extern char *varobj_get_path_expr (struct varobj *var);
+extern char *varobj_get_path_expr (const struct varobj *var);
 
 extern const struct language_defn *
   varobj_get_language (const struct varobj *var);
@@ -329,7 +329,8 @@ extern struct type *varobj_get_value_type (const struct varobj *var);
 
 extern int varobj_is_anonymous_child (const struct varobj *child);
 
-extern struct varobj *varobj_get_path_expr_parent (struct varobj *var);
+extern const struct varobj *
+  varobj_get_path_expr_parent (const struct varobj *var);
 
 extern char *varobj_value_get_print_value (struct value *value,
 					   enum varobj_display_formats format,