xref: /dragonfly/contrib/gdb-7/gdb/go-valprint.c (revision 0db87cb7)
1 /* Support for printing Go values for GDB, the GNU debugger.
2 
3    Copyright (C) 2012-2013 Free Software Foundation, Inc.
4 
5    This file is part of GDB.
6 
7    This program is free software; you can redistribute it and/or modify
8    it under the terms of the GNU General Public License as published by
9    the Free Software Foundation; either version 3 of the License, or
10    (at your option) any later version.
11 
12    This program is distributed in the hope that it will be useful,
13    but WITHOUT ANY WARRANTY; without even the implied warranty of
14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15    GNU General Public License for more details.
16 
17    You should have received a copy of the GNU General Public License
18    along with this program.  If not, see <http://www.gnu.org/licenses/>.
19 
20    NOTE: This currently only provides special support for printing gccgo
21    strings.  6g objects are handled in Python.
22    The remaining gccgo types may also be handled in Python.
23    Strings are handled specially here, at least for now, in case the Python
24    support is unavailable.  */
25 
26 #include "defs.h"
27 #include "gdbtypes.h"
28 #include "gdbcore.h"
29 #include "go-lang.h"
30 #include "c-lang.h"
31 #include "valprint.h"
32 
33 /* Print a Go string.
34 
35    Note: We assume
36    gdb_assert (go_classify_struct_type (type) == GO_TYPE_STRING).  */
37 
38 static void
39 print_go_string (struct type *type, const gdb_byte *valaddr,
40 		 int embedded_offset, CORE_ADDR address,
41 		 struct ui_file *stream, int recurse,
42 		 const struct value *val,
43 		 const struct value_print_options *options)
44 {
45   struct gdbarch *gdbarch = get_type_arch (type);
46   struct type *elt_ptr_type = TYPE_FIELD_TYPE (type, 0);
47   struct type *elt_type = TYPE_TARGET_TYPE (elt_ptr_type);
48   LONGEST length;
49   /* TODO(dje): The encapsulation of what a pointer is belongs in value.c.
50      I.e. If there's going to be unpack_pointer, there should be
51      unpack_value_field_as_pointer.  Do this until we can get
52      unpack_value_field_as_pointer.  */
53   LONGEST addr;
54 
55   gdb_assert (valaddr == value_contents_for_printing_const (val));
56 
57   if (! unpack_value_field_as_long (type, valaddr, embedded_offset, 0,
58 				    val, &addr))
59     error (_("Unable to read string address"));
60 
61   if (! unpack_value_field_as_long (type, valaddr, embedded_offset, 1,
62 				    val, &length))
63     error (_("Unable to read string length"));
64 
65   /* TODO(dje): Print address of struct or actual string?  */
66   if (options->addressprint)
67     {
68       fputs_filtered (paddress (gdbarch, addr), stream);
69       fputs_filtered (" ", stream);
70     }
71 
72   if (length < 0)
73     {
74       fputs_filtered (_("<invalid length: "), stream);
75       fputs_filtered (plongest (addr), stream);
76       fputs_filtered (">", stream);
77       return;
78     }
79 
80   /* TODO(dje): Perhaps we should pass "UTF8" for ENCODING.
81      The target encoding is a global switch.
82      Either choice is problematic.  */
83   val_print_string (elt_type, NULL, addr, length, stream, options);
84 }
85 
86 /* Implements the la_val_print routine for language Go.  */
87 
88 void
89 go_val_print (struct type *type, const gdb_byte *valaddr, int embedded_offset,
90 	      CORE_ADDR address, struct ui_file *stream, int recurse,
91 	      const struct value *val,
92 	      const struct value_print_options *options)
93 {
94   CHECK_TYPEDEF (type);
95 
96   switch (TYPE_CODE (type))
97     {
98       case TYPE_CODE_STRUCT:
99 	{
100 	  enum go_type go_type = go_classify_struct_type (type);
101 
102 	  switch (go_type)
103 	    {
104 	    case GO_TYPE_STRING:
105 	      if (! options->raw)
106 		{
107 		  print_go_string (type, valaddr, embedded_offset, address,
108 				   stream, recurse, val, options);
109 		  return;
110 		}
111 	      break;
112 	    default:
113 	      break;
114 	    }
115 	}
116 	/* Fall through.  */
117 
118       default:
119 	c_val_print (type, valaddr, embedded_offset, address, stream,
120 		     recurse, val, options);
121 	break;
122     }
123 }
124