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, 25 insertions, 45 deletions

diff --git a/gdb/mi/mi-cmd-var.c b/gdb/mi/mi-cmd-var.c
index 16d51f9c86..147e0265b0 100644
--- a/gdb/mi/mi-cmd-var.c
+++ b/gdb/mi/mi-cmd-var.c
@@ -49,34 +49,28 @@ print_varobj (struct varobj *var, enum print_values print_values,
 	      int print_expression)
 {
   struct ui_out *uiout = current_uiout;
-  char *type;
   int thread_id;
   char *display_hint;
 
   ui_out_field_string (uiout, "name", varobj_get_objname (var));
   if (print_expression)
     {
-      char *exp = varobj_get_expression (var);
+      std::string exp = varobj_get_expression (var);
 
-      ui_out_field_string (uiout, "exp", exp);
-      xfree (exp);
+      ui_out_field_string (uiout, "exp", exp.c_str ());
     }
   ui_out_field_int (uiout, "numchild", varobj_get_num_children (var));
   
   if (mi_print_value_p (var, print_values))
     {
-      char *val = varobj_get_value (var);
+      std::string val = varobj_get_value (var);
 
-      ui_out_field_string (uiout, "value", val);
-      xfree (val);
+      ui_out_field_string (uiout, "value", val.c_str ());
     }
 
-  type = varobj_get_type (var);
-  if (type != NULL)
-    {
-      ui_out_field_string (uiout, "type", type);
-      xfree (type);
-    }
+  std::string type = varobj_get_type (var);
+  if (!type.empty ())
+    ui_out_field_string (uiout, "type", type.c_str ());
 
   thread_id = varobj_get_thread_id (var);
   if (thread_id > 0)
@@ -246,7 +240,6 @@ mi_cmd_var_set_format (char *command, char **argv, int argc)
 {
   enum varobj_display_formats format;
   struct varobj *var;
-  char *val;
   struct ui_out *uiout = current_uiout;
 
   if (argc != 2)
@@ -264,9 +257,8 @@ mi_cmd_var_set_format (char *command, char **argv, int argc)
   ui_out_field_string (uiout, "format", varobj_format_string[(int) format]);
  
   /* Report the value in the new format.  */
-  val = varobj_get_value (var);
-  ui_out_field_string (uiout, "value", val);
-  xfree (val);
+  std::string val = varobj_get_value (var);
+  ui_out_field_string (uiout, "value", val.c_str ());
 }
 
 void
@@ -454,18 +446,15 @@ mi_cmd_var_info_type (char *command, char **argv, int argc)
 {
   struct ui_out *uiout = current_uiout;
   struct varobj *var;
-  char *type_name;
 
   if (argc != 1)
     error (_("-var-info-type: Usage: NAME."));
 
   /* Get varobj handle, if a valid var obj name was specified.  */
   var = varobj_get_handle (argv[0]);
-  type_name = varobj_get_type (var);
-
-  ui_out_field_string (uiout, "type", type_name);
 
-  xfree (type_name);
+  std::string type_name = varobj_get_type (var);
+  ui_out_field_string (uiout, "type", type_name.c_str ());
 }
 
 void
@@ -473,7 +462,6 @@ mi_cmd_var_info_path_expression (char *command, char **argv, int argc)
 {
   struct ui_out *uiout = current_uiout;
   struct varobj *var;
-  char *path_expr;
 
   if (argc != 1)
     error (_("Usage: NAME."));
@@ -481,7 +469,7 @@ mi_cmd_var_info_path_expression (char *command, char **argv, int argc)
   /* Get varobj handle, if a valid var obj name was specified.  */
   var = varobj_get_handle (argv[0]);
   
-  path_expr = varobj_get_path_expr (var);
+  const char *path_expr = varobj_get_path_expr (var);
 
   ui_out_field_string (uiout, "path_expr", path_expr);
 }
@@ -492,7 +480,6 @@ mi_cmd_var_info_expression (char *command, char **argv, int argc)
   struct ui_out *uiout = current_uiout;
   const struct language_defn *lang;
   struct varobj *var;
-  char *exp;
 
   if (argc != 1)
     error (_("-var-info-expression: Usage: NAME."));
@@ -504,9 +491,8 @@ mi_cmd_var_info_expression (char *command, char **argv, int argc)
 
   ui_out_field_string (uiout, "lang", lang->la_natural_name);
 
-  exp = varobj_get_expression (var);
-  ui_out_field_string (uiout, "exp", exp);
-  xfree (exp);
+  std::string exp = varobj_get_expression (var);
+  ui_out_field_string (uiout, "exp", exp.c_str ());
 }
 
 void
@@ -588,17 +574,15 @@ mi_cmd_var_evaluate_expression (char *command, char **argv, int argc)
    
   if (formatFound)
     {
-      char *val = varobj_get_formatted_value (var, format);
+      std::string val = varobj_get_formatted_value (var, format);
 
-      ui_out_field_string (uiout, "value", val);
-      xfree (val);
+      ui_out_field_string (uiout, "value", val.c_str ());
     }
   else
     {
-      char *val = varobj_get_value (var);
+      std::string val = varobj_get_value (var);
 
-      ui_out_field_string (uiout, "value", val);
-      xfree (val);
+      ui_out_field_string (uiout, "value", val.c_str ());
     }
 }
 
@@ -607,7 +591,6 @@ mi_cmd_var_assign (char *command, char **argv, int argc)
 {
   struct ui_out *uiout = current_uiout;
   struct varobj *var;
-  char *expression, *val;
 
   if (argc != 2)
     error (_("-var-assign: Usage: NAME EXPRESSION."));
@@ -618,7 +601,7 @@ mi_cmd_var_assign (char *command, char **argv, int argc)
   if (!varobj_editable_p (var))
     error (_("-var-assign: Variable object is not editable"));
 
-  expression = xstrdup (argv[1]);
+  const char *expression = argv[1];
 
   /* MI command '-var-assign' may write memory, so suppress memory
      changed notification if it does.  */
@@ -629,9 +612,8 @@ mi_cmd_var_assign (char *command, char **argv, int argc)
     error (_("-var-assign: Could not assign "
 	     "expression to variable object"));
 
-  val = varobj_get_value (var);
-  ui_out_field_string (uiout, "value", val);
-  xfree (val);
+  std::string val = varobj_get_value (var);
+  ui_out_field_string (uiout, "value", val.c_str ());
 }
 
 /* Type used for parameters passing to mi_cmd_var_update_iter.  */
@@ -752,10 +734,9 @@ varobj_update_one (struct varobj *var, enum print_values print_values,
 	case VAROBJ_IN_SCOPE:
 	  if (mi_print_value_p (r->varobj, print_values))
 	    {
-	      char *val = varobj_get_value (r->varobj);
+	      std::string val = varobj_get_value (r->varobj);
 
-	      ui_out_field_string (uiout, "value", val);
-	      xfree (val);
+	      ui_out_field_string (uiout, "value", val.c_str ());
 	    }
 	  ui_out_field_string (uiout, "in_scope", "true");
 	  break;
@@ -777,10 +758,9 @@ varobj_update_one (struct varobj *var, enum print_values print_values,
 
       if (r->type_changed)
 	{
-	  char *type_name = varobj_get_type (r->varobj);
+	  std::string type_name = varobj_get_type (r->varobj);
 
-	  ui_out_field_string (uiout, "new_type", type_name);
-	  xfree (type_name);
+	  ui_out_field_string (uiout, "new_type", type_name.c_str ());
 	}
 
       if (r->type_changed || r->children_changed)