binutils-gdb/gdb/jv-varobj.c
Andrew Burgess 9a9a760829 Improve MI -var-info-path-expression for nested struct/union case.
https://sourceware.org/ml/gdb-patches/2014-05/msg00383.html

The MI command -var-info-path-expression currently does not handle
non-anonymous structs / unions nested within other structs / unions,
it will skip parts of the expression.  Consider this example:

  ## START EXAMPLE ##
  $ cat ex.c
  #include <string.h>

  int
  main ()
  {
    struct s1
    {
      int a;
    };

    struct ss
    {
      struct s1 x;
    };

    struct ss an_ss;
    memset (&an_ss, 0, sizeof (an_ss));
    return 0;
  }
  $ gcc -g -o ex.x ex.c
  $ gdb ex.x
  (gdb) break 18
  Breakpoint 1 at 0x80483ba: file ex.c, line 18.
  (gdb) run
  Starting program: /home/user/ex.x

  Breakpoint 1, main () at ex.c:18
  18	  return 0;
  (gdb) interpreter-exec mi "-var-create an_ss * an_ss"
  (gdb) interpreter-exec mi "-var-list-children an_ss"
  ^done,numchild="1",children=[child={name="an_ss.x",exp="x",numchild="1",type="struct s1",thread-id="1"}],has_more="0"
  (gdb) interpreter-exec mi "-var-list-children an_ss.x"
  ^done,numchild="1",children=[child={name="an_ss.x.a",exp="a",numchild="0",type="int",thread-id="1"}],has_more="0"
  (gdb) interpreter-exec mi "-var-list-children an_ss.x.a"
  ^done,numchild="0",has_more="0"
  (gdb) interpreter-exec mi "-var-info-path-expression an_ss.x.a"
  ^done,path_expr="(an_ss).a"
  (gdb) print (an_ss).a
  There is no member named a.
  ## END EXAMPLE ##

Notice that the path expression returned is wrong, and as a result
the print command fails.

This patch adds a new method to the varobj_ops structure called
is_path_expr_parent, to allow language specific control over finding
the parent varobj, the current logic becomes the C/C++ version and is
extended to handle the nested cases.  No other language currently uses
this code, so all other languages just get a default method.

With this patch, the above example now finishes like this:

  ## START EXAMPLE ##
  $ gdb ex.x
  (gdb) break 18
  Breakpoint 1 at 0x80483ba: file ex.c, line 18.
  (gdb) run
  Starting program: /home/user/ex.x

  Breakpoint 1, main () at ex.c:18
  18	  return 0;
  (gdb) interpreter-exec mi "-var-list-children an_ss"
  ^done,numchild="1",children=[child={name="an_ss.x",exp="x",numchild="1",type="struct s1",thread-id="1"}],has_more="0"
  (gdb) interpreter-exec mi "-var-list-children an_ss.x"
  ^done,numchild="1",children=[child={name="an_ss.x.a",exp="a",numchild="0",type="int",thread-id="1"}],has_more="0"
  (gdb) interpreter-exec mi "-var-list-children an_ss.x.a"
  ^done,numchild="0",has_more="0"
  (gdb) interpreter-exec mi "-var-info-path-expression an_ss.x.a"
  ^done,path_expr="((an_ss).x).a"
  (gdb) print ((an_ss).x).a
  $1 = 0
  ## END EXAMPLE ##

Notice that the path expression is now correct, and the print is a
success.

gdb/ChangeLog:

	* ada-varobj.c (ada_varobj_ops): Fill in is_path_expr_parent
	field.
	* c-varobj.c (c_is_path_expr_parent): New function, moved core
	from varobj.c, with additional checks.
	(c_varobj_ops): Fill in is_path_expr_parent field.
	(cplus_varobj_ops): Fill in is_path_expr_parent field.
	* jv-varobj.c (java_varobj_ops): Fill in is_path_expr_parent
	field.
	* varobj.c (is_path_expr_parent): Call is_path_expr_parent varobj
	ops method.
	(varobj_default_is_path_expr_parent): New function.
	* varobj.h (lang_varobj_ops): Add is_path_expr_parent field.
	(varobj_default_is_path_expr_parent): Declare new function.

gdb/testsuite/ChangeLog:

	* gdb.mi/var-cmd.c (do_nested_struct_union_tests): New function
	setting up test structures.
	(main): Call new test function.
	* gdb.mi/mi2-var-child.exp: Create additional breakpoint in new
	test function, continue into test function and walk test
	structures.
2014-07-09 14:47:47 +01:00

107 lines
2.4 KiB
C

/* varobj support for Java.
Copyright (C) 1999-2014 Free Software Foundation, Inc.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>. */
#include "defs.h"
#include "varobj.h"
/* Java */
static int
java_number_of_children (struct varobj *var)
{
return cplus_varobj_ops.number_of_children (var);
}
static char *
java_name_of_variable (struct varobj *parent)
{
char *p, *name;
name = cplus_varobj_ops.name_of_variable (parent);
/* If the name has "-" in it, it is because we
needed to escape periods in the name... */
p = name;
while (*p != '\000')
{
if (*p == '-')
*p = '.';
p++;
}
return name;
}
static char *
java_name_of_child (struct varobj *parent, int index)
{
char *name, *p;
name = cplus_varobj_ops.name_of_child (parent, index);
/* Escape any periods in the name... */
p = name;
while (*p != '\000')
{
if (*p == '.')
*p = '-';
p++;
}
return name;
}
static char *
java_path_expr_of_child (struct varobj *child)
{
return NULL;
}
static struct value *
java_value_of_child (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)
{
return cplus_varobj_ops.type_of_child (parent, index);
}
static char *
java_value_of_variable (struct varobj *var, enum varobj_display_formats format)
{
return cplus_varobj_ops.value_of_variable (var, format);
}
/* varobj operations for java. */
const struct lang_varobj_ops java_varobj_ops =
{
java_number_of_children,
java_name_of_variable,
java_name_of_child,
java_path_expr_of_child,
java_value_of_child,
java_type_of_child,
java_value_of_variable,
varobj_default_value_is_changeable_p,
NULL, /* value_has_mutated */
varobj_default_is_path_expr_parent
};