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, 35 deletions

diff --git a/gdb/cp-support.c b/gdb/cp-support.c
index ea6dcb2fe2..d409b0b92e 100644
--- a/gdb/cp-support.c
+++ b/gdb/cp-support.c
@@ -288,14 +288,12 @@ inspect_type (struct demangle_parse_info *info,
 
 		 Canonicalize the name again, and store it in the
 		 current node (RET_COMP).  */
-	      char *canon = cp_canonicalize_string_no_typedefs (name);
+	      std::string canon = cp_canonicalize_string_no_typedefs (name);
 
-	      if (canon != NULL)
+	      if (!canon.empty ())
 		{
-		  /* Copy the canonicalization into the obstack and
-		     free CANON.  */
-		  name = copy_string_to_obstack (&info->obstack, canon, &len);
-		  xfree (canon);
+		  /* Copy the canonicalization into the obstack.  */
+		  name = copy_string_to_obstack (&info->obstack, canon.c_str (), &len);
 		}
 
 	      ret_comp->u.s_name.s = name;
@@ -529,22 +527,21 @@ replace_typedefs (struct demangle_parse_info *info,
     }
 }
 
-/* Parse STRING and convert it to canonical form, resolving any typedefs.
-   If parsing fails, or if STRING is already canonical, return NULL.
-   Otherwise return the canonical form.  The return value is allocated via
-   xmalloc.  If FINDER is not NULL, then type components are passed to
-   FINDER to be looked up.  DATA is passed verbatim to FINDER.  */
+/* Parse STRING and convert it to canonical form, resolving any
+   typedefs.  If parsing fails, or if STRING is already canonical,
+   return the empty string.  Otherwise return the canonical form.  If
+   FINDER is not NULL, then type components are passed to FINDER to be
+   looked up.  DATA is passed verbatim to FINDER.  */
 
-char *
+std::string
 cp_canonicalize_string_full (const char *string,
 			     canonicalization_ftype *finder,
 			     void *data)
 {
-  char *ret;
+  std::string ret;
   unsigned int estimated_len;
   struct demangle_parse_info *info;
 
-  ret = NULL;
   estimated_len = strlen (string) * 2;
   info = cp_demangled_name_to_comp (string, NULL);
   if (info != NULL)
@@ -554,18 +551,15 @@ cp_canonicalize_string_full (const char *string,
 
       /* Convert the tree back into a string.  */
       ret = cp_comp_to_string (info->tree, estimated_len);
-      gdb_assert (ret != NULL);
+      gdb_assert (!ret.empty ());
 
       /* Free the parse information.  */
       cp_demangled_name_parse_free (info);
 
       /* Finally, compare the original string with the computed
 	 name, returning NULL if they are the same.  */
-      if (strcmp (string, ret) == 0)
-	{
-	  xfree (ret);
-	  return NULL;
-	}
+      if (ret == string)
+	return std::string ();
     }
 
   return ret;
@@ -574,46 +568,42 @@ cp_canonicalize_string_full (const char *string,
 /* Like cp_canonicalize_string_full, but always passes NULL for
    FINDER.  */
 
-char *
+std::string
 cp_canonicalize_string_no_typedefs (const char *string)
 {
   return cp_canonicalize_string_full (string, NULL, NULL);
 }
 
 /* Parse STRING and convert it to canonical form.  If parsing fails,
-   or if STRING is already canonical, return NULL.  Otherwise return
-   the canonical form.  The return value is allocated via xmalloc.  */
+   or if STRING is already canonical, return the empty string.
+   Otherwise return the canonical form.  */
 
-char *
+std::string
 cp_canonicalize_string (const char *string)
 {
   struct demangle_parse_info *info;
   unsigned int estimated_len;
-  char *ret;
 
   if (cp_already_canonical (string))
-    return NULL;
+    return std::string ();
 
   info = cp_demangled_name_to_comp (string, NULL);
   if (info == NULL)
-    return NULL;
+    return std::string ();
 
   estimated_len = strlen (string) * 2;
-  ret = cp_comp_to_string (info->tree, estimated_len);
+  std::string ret = cp_comp_to_string (info->tree, estimated_len);
   cp_demangled_name_parse_free (info);
 
-  if (ret == NULL)
+  if (ret.empty ())
     {
       warning (_("internal error: string \"%s\" failed to be canonicalized"),
 	       string);
-      return NULL;
+      return std::string ();
     }
 
-  if (strcmp (string, ret) == 0)
-    {
-      xfree (ret);
-      return NULL;
-    }
+  if (ret == string)
+    return std::string ();
 
   return ret;
 }