Use ui_file_as_string throughout more

This replaces most of the remaining ui_file_xstrdup calls with
ui_file_as_string calls.  Whenever a call was replaced, that led to a
cascade of other necessary adjustments throughout, to make the code
use std::string instead of raw pointers.  And then whenever I added a
std::string as member of a struct, I needed to adjust
allocation/destruction of said struct to use new/delete instead of
xmalloc/xfree.

The stopping point was once gdb built again.  These doesn't seem to be
a way to reasonably split this out further.

Maybe-not-obvious changes:

 - demangle_for_lookup returns a cleanup today.  To get rid of that,
   and avoid unnecessary string dupping/copying, this introduces a
   demangle_result_storage type that the caller instantiates and
   passes to demangle_for_lookup.

 - Many methods returned a "char *" to indicate that the caller owns
   the memory and must free it.  Those are switched to return a
   std::string instead.  Methods that return a "view" into some
   internal string return a "const char *" instead.  I.e., we only
   copy/allocate when necessary.

gdb/ChangeLog:
2016-11-08  Pedro Alves  <palves@redhat.com>

	* ada-lang.c (ada_name_for_lookup, type_as_string): Use and return
	std::string.
	(type_as_string_and_cleanup): Delete.
	(ada_lookup_struct_elt_type): Use type_as_string.
	* ada-lang.h (ada_name_for_lookup): Now returns std::string.
	* ada-varobj.c (ada_varobj_scalar_image): Return a std::string.
	(ada_varobj_describe_child): Make 'child_name' and
	'child_path_expr' parameters std::string pointers.
	(ada_varobj_describe_struct_child, ada_varobj_describe_ptr_child):
	Likewise, and use string_printf.
	(ada_varobj_describe_simple_array_child)
	(ada_varobj_describe_child): Likewise.
	(ada_varobj_get_name_of_child, ada_varobj_get_path_expr_of_child)
	(ada_varobj_get_value_image)
	(ada_varobj_get_value_of_array_variable)
	(ada_varobj_get_value_of_variable, ada_name_of_variable)
	(ada_name_of_child, ada_path_expr_of_child)
	(ada_value_of_variable): Now returns std::string.  Use
	string_printf.
	(ada_value_of_child): Adjust.
	* break-catch-throw.c (check_status_exception_catchpoint): Adjust
	to use std::string.
	* breakpoint.c (watch_command_1): Adjust to use std::string.
	* c-lang.c (c_get_string): Adjust to use std::string.
	* c-typeprint.c (print_name_maybe_canonical): Use std::string.
	* c-varobj.c (varobj_is_anonymous_child): Use ==/!= std::string
	operators.
	(c_name_of_variable): Now returns a std::string.
	(c_describe_child): The 'cname' and 'cfull_expression' output
	parameters are now std::string pointers.  Adjust.
	(c_name_of_child, c_path_expr_of_child, c_value_of_variable)
	(cplus_number_of_children): Adjust to use std::string and
	string_printf.
	(cplus_name_of_variable): Now returns a std::string.
	(cplus_describe_child): The 'cname' and 'cfull_expression' output
	parameters are now std::string pointers.  Adjust.
	(cplus_name_of_child, cplus_path_expr_of_child)
	(cplus_value_of_variable): Now returns a std::string.
	* cp-abi.c (cplus_typename_from_type_info): Return std::string.
	* cp-abi.h (cplus_typename_from_type_info): Return std::string.
	(struct cp_abi_ops) <get_typename_from_type_info>: Return
	std::string.
	* cp-support.c (inspect_type): Use std::string.
	(cp_canonicalize_string_full, cp_canonicalize_string_no_typedefs)
	(cp_canonicalize_string): Return std::string and adjust.
	* cp-support.h (cp_canonicalize_string)
	(cp_canonicalize_string_no_typedefs, cp_canonicalize_string_full):
	Return std::string.
	* dbxread.c (read_dbx_symtab): Use std::string.
	* dwarf2read.c (dwarf2_canonicalize_name): Adjust to use std::string.
	* gdbcmd.h (lookup_struct_elt_type): Adjust to use std::string.
	* gnu-v3-abi.c (gnuv3_get_typeid): Use std::string.
	(gnuv3_get_typename_from_type_info): Return a std::string and
	adjust.
	(gnuv3_get_type_from_type_info): Adjust to use std::string.
	* guile/guile.c (gdbscm_execute_gdb_command): Adjust to use
	std::string.
	* infcmd.c (print_return_value_1): Adjust to use std::string.
	* linespec.c (find_linespec_symbols): Adjust to
	demangle_for_lookup API change.  Use std::string.
	* mi/mi-cmd-var.c (print_varobj, mi_cmd_var_set_format)
	(mi_cmd_var_info_type, mi_cmd_var_info_path_expression)
	(mi_cmd_var_info_expression, mi_cmd_var_evaluate_expression)
	(mi_cmd_var_assign, varobj_update_one): Adjust to use std::string.
	* minsyms.c (lookup_minimal_symbol): Use std::string.
	* python/py-varobj.c (py_varobj_iter_next): Use new instead of
	XNEW.  vitem->name is a std::string now, adjust.
	* rust-exp.y (convert_ast_to_type, convert_name): Adjust to use
	std::string.
	* stabsread.c (define_symbol): Adjust to use std::string.
	* symtab.c (demangle_for_lookup): Now returns 'const char *'.  Add
	a demangle_result_storage parameter.  Use it for storage.
	(lookup_symbol_in_language)
	(lookup_symbol_in_objfile_from_linkage_name): Adjust to new
	demangle_for_lookup API.
	* symtab.h (struct demangle_result_storage): New type.
	(demangle_for_lookup): Now returns 'const char *'.  Add a
	demangle_result_storage parameter.
	* typeprint.c (type_to_string): Return std::string and use
	ui_file_as_string.
	* value.h (type_to_string): Change return type to std::string.
	* varobj-iter.h (struct varobj_item) <name>: Now a std::string.
	(varobj_iter_delete): Use delete instead of xfree.
	* varobj.c (create_child): Return std::string instead of char * in
	output parameter.
	(name_of_variable, name_of_child, my_value_of_variable): Return
	std::string instead of char *.
	(varobj_create, varobj_get_handle): Constify 'objname' parameter.
	Adjust to std::string fields.
	(varobj_get_objname): Return a const char * instead of a char *.
	(varobj_get_expression): Return a std::string.
	(varobj_list_children): Adjust to use std::string.
	(varobj_get_type): Return a std::string.
	(varobj_get_path_expr): Return a const char * instead of a char *.
	Adjust to std::string fields.
	(varobj_get_formatted_value, varobj_get_value): Return a
	std::string.
	(varobj_set_value): Change type of 'expression' parameter to
	std::string.  Use std::string.
	(install_new_value): Use std::string.
	(delete_variable_1): Adjust to use std::string.
	(create_child): Change the 'name' parameter to a std::string
	reference.  Swap it into the new item's name.
	(create_child_with_value): Swap item's name into the new child's
	name.  Use string_printf.
	(new_variable): Use new instead of XNEW.
	(free_variable): Don't xfree fields that are now std::string.
	(name_of_variable, name_of_child): Now returns std::string.
	(value_of_root): Adjust to use std::string.
	(my_value_of_variable, varobj_value_get_print_value): Return
	and use std::string.
	(varobj_value_get_print_value): Adjust to use ui_file_as_string
	and std::string.
	* varobj.h (struct varobj) <name, path_expr, obj_name,
	print_value>: Now std::string's.
	<name_of_variable, name_of_child, path_expr_of_child,
	value_of_variable>: Return std::string.
	(varobj_create, varobj_get_handle): Constify 'objname' parameter.
	(varobj_get_objname): Return a const char * instead of a char *.
	(varobj_get_expression, varobj_get_type): Return a std::string.
	(varobj_get_path_expr): Return a const char * instead of a char *.
	(varobj_get_formatted_value, varobj_get_value): Return a
	std::string.
	(varobj_set_value): Constify 'expression' parameter.
	(varobj_value_get_print_value): Return a std::string.

1 files changed, 34 insertions, 36 deletions

diff --git a/gdb/varobj.h b/gdb/varobj.h
index 6b9a71f7037..7f4aad24209 100644
--- a/gdb/varobj.h
+++ b/gdb/varobj.h
@@ -86,22 +86,22 @@ struct varobj_dynamic;
 
 /* Every variable in the system has a structure of this type defined
    for it.  This structure holds all information necessary to manipulate
-   a particular object variable.  Members which must be freed are noted.  */
+   a particular object variable.  */
 struct varobj
 {
-  /* Alloc'd name of the variable for this object.  If this variable is a
+  /* Name of the variable for this object.  If this variable is a
      child, then this name will be the child's source name.
      (bar, not foo.bar).  */
   /* NOTE: This is the "expression".  */
-  char *name;
+  std::string name;
 
-  /* Alloc'd expression for this child.  Can be used to create a
-     root variable corresponding to this child.  */
-  char *path_expr;
+  /* Expression for this child.  Can be used to create a root variable
+     corresponding to this child.  */
+  std::string path_expr;
 
-  /* The alloc'd name for this variable's object.  This is here for
+  /* The name for this variable's object.  This is here for
      convenience when constructing this object's children.  */
-  char *obj_name;
+  std::string obj_name;
 
   /* Index of this variable in its parent or -1.  */
   int index;
@@ -137,7 +137,7 @@ struct varobj
   int updated;
 
   /* Last print value.  */
-  char *print_value;
+  std::string print_value;
 
   /* Is this variable frozen.  Frozen variables are never implicitly
      updated by -var-update * 
@@ -170,18 +170,15 @@ struct lang_varobj_ops
   /* The number of children of PARENT.  */
   int (*number_of_children) (const struct varobj *parent);
 
-  /* The name (expression) of a root varobj.  The returned value must be freed
-     by the caller.  */
-  char *(*name_of_variable) (const struct varobj *parent);
+  /* The name (expression) of a root varobj.  */
+  std::string (*name_of_variable) (const struct varobj *parent);
 
-  /* The name of the INDEX'th child of PARENT.  The returned value must be
-     freed by the caller.  */
-  char *(*name_of_child) (const struct varobj *parent, int index);
+  /* The name of the INDEX'th child of PARENT.  */
+  std::string (*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
-     caller.  */
-  char *(*path_expr_of_child) (const struct varobj *child);
+     obtain that has some parent.  */
+  std::string (*path_expr_of_child) (const struct varobj *child);
 
   /* The ``struct value *'' of the INDEX'th child of PARENT.  */
   struct value *(*value_of_child) (const struct varobj *parent, int index);
@@ -189,10 +186,9 @@ struct lang_varobj_ops
   /* The type of the INDEX'th child of PARENT.  */
   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.  */
-  char *(*value_of_variable) (const struct varobj *var,
-			      enum varobj_display_formats format);
+  /* The current value of VAR.  */
+  std::string (*value_of_variable) (const struct varobj *var,
+				    enum varobj_display_formats format);
 
   /* Return non-zero if changes in value of VAR must be detected and
      reported by -var-update.  Return zero if -var-update should never
@@ -233,17 +229,17 @@ extern const struct lang_varobj_ops ada_varobj_ops;
 #define default_varobj_ops c_varobj_ops
 /* API functions */
 
-extern struct varobj *varobj_create (char *objname,
-				     char *expression, CORE_ADDR frame,
+extern struct varobj *varobj_create (const char *objname,
+				     const char *expression, CORE_ADDR frame,
 				     enum varobj_type type);
 
 extern char *varobj_gen_name (void);
 
-extern struct varobj *varobj_get_handle (char *name);
+extern struct varobj *varobj_get_handle (const char *name);
 
-extern char *varobj_get_objname (const struct varobj *var);
+extern const char *varobj_get_objname (const struct varobj *var);
 
-extern char *varobj_get_expression (const struct varobj *var);
+extern std::string varobj_get_expression (const struct varobj *var);
 
 /* Delete a varobj and all its children if only_children == 0, otherwise delete
    only the children.  Return the number of deleted variables.  */
@@ -283,23 +279,24 @@ extern int varobj_get_num_children (struct varobj *var);
 extern VEC (varobj_p)* varobj_list_children (struct varobj *var,
 					     int *from, int *to);
 
-extern char *varobj_get_type (struct varobj *var);
+extern std::string varobj_get_type (struct varobj *var);
 
 extern struct type *varobj_get_gdb_type (const struct varobj *var);
 
-extern char *varobj_get_path_expr (const struct varobj *var);
+extern const char *varobj_get_path_expr (const struct varobj *var);
 
 extern const struct language_defn *
   varobj_get_language (const struct varobj *var);
 
 extern int varobj_get_attributes (const struct varobj *var);
 
-extern char *varobj_get_formatted_value (struct varobj *var,
-					 enum varobj_display_formats format);
+extern std::string
+  varobj_get_formatted_value (struct varobj *var,
+			      enum varobj_display_formats format);
 
-extern char *varobj_get_value (struct varobj *var);
+extern std::string varobj_get_value (struct varobj *var);
 
-extern int varobj_set_value (struct varobj *var, char *expression);
+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);
@@ -334,9 +331,10 @@ extern int varobj_is_anonymous_child (const struct varobj *child);
 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,
-					   const struct varobj *var);
+extern std::string
+  varobj_value_get_print_value (struct value *value,
+				enum varobj_display_formats format,
+				const struct varobj *var);
 
 extern void varobj_formatted_print_options (struct value_print_options *opts,
 					    enum varobj_display_formats format);