gdb/gdb-gdb.py.in

   1 # Copyright (C) 2009-2020 Free Software Foundation, Inc.
   2 #
   3 # This file is part of GDB.
   4 #
   5 # This program is free software; you can redistribute it and/or modify
   6 # it under the terms of the GNU General Public License as published by
   7 # the Free Software Foundation; either version 3 of the License, or
   8 # (at your option) any later version.
   9 #
  10 # This program is distributed in the hope that it will be useful,
  11 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  12 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13 # GNU General Public License for more details.
  14 #
  15 # You should have received a copy of the GNU General Public License
  16 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
  17
  18 import gdb
  19 import os.path
  20
  21
  22 class TypeFlag:
  23     """A class that allows us to store a flag name, its short name,
  24     and its value.
  25
  26     In the GDB sources, struct type has a component called instance_flags
  27     in which the value is the addition of various flags.  These flags are
  28     defined by the enumerates type_instance_flag_value.  This class helps us
  29     recreate a list with all these flags that is easy to manipulate and sort.
  30     Because all flag names start with TYPE_INSTANCE_FLAG_, a short_name
  31     attribute is provided that strips this prefix.
  32
  33     ATTRIBUTES
  34       name:  The enumeration name (eg: "TYPE_INSTANCE_FLAG_CONST").
  35       value: The associated value.
  36       short_name: The enumeration name, with the suffix stripped.
  37     """
  38
  39     def __init__(self, name, value):
  40         self.name = name
  41         self.value = value
  42         self.short_name = name.replace("TYPE_INSTANCE_FLAG_", '')
  43
  44     def __lt__(self, other):
  45         """Sort by value order."""
  46         return self.value < other.value
  47
  48
  49 # A list of all existing TYPE_INSTANCE_FLAGS_* enumerations,
  50 # stored as TypeFlags objects.  Lazy-initialized.
  51 TYPE_FLAGS = None
  52
  53
  54 class TypeFlagsPrinter:
  55     """A class that prints a decoded form of an instance_flags value.
  56
  57     This class uses a global named TYPE_FLAGS, which is a list of
  58     all defined TypeFlag values.  Using a global allows us to compute
  59     this list only once.
  60
  61     This class relies on a couple of enumeration types being defined.
  62     If not, then printing of the instance_flag is going to be degraded,
  63     but it's not a fatal error.
  64     """
  65
  66     def __init__(self, val):
  67         self.val = val
  68
  69     def __str__(self):
  70         global TYPE_FLAGS
  71         if TYPE_FLAGS is None:
  72             self.init_TYPE_FLAGS()
  73         if not self.val:
  74             return "0"
  75         if TYPE_FLAGS:
  76             flag_list = [flag.short_name for flag in TYPE_FLAGS
  77                          if self.val & flag.value]
  78         else:
  79             flag_list = ["???"]
  80         return "0x%x [%s]" % (self.val, "|".join(flag_list))
  81
  82     def init_TYPE_FLAGS(self):
  83         """Initialize the TYPE_FLAGS global as a list of TypeFlag objects.
  84         This operation requires the search of a couple of enumeration types.
  85         If not found, a warning is printed on stdout, and TYPE_FLAGS is
  86         set to the empty list.
  87
  88         The resulting list is sorted by increasing value, to facilitate
  89         printing of the list of flags used in an instance_flags value.
  90         """
  91         global TYPE_FLAGS
  92         TYPE_FLAGS = []
  93         try:
  94             iflags = gdb.lookup_type("enum type_instance_flag_value")
  95         except:
  96             print("Warning: Cannot find enum type_instance_flag_value type.")
  97             print("         `struct type' pretty-printer will be degraded")
  98             return
  99         TYPE_FLAGS = [TypeFlag(field.name, field.enumval)
 100                       for field in iflags.fields()]
 101         TYPE_FLAGS.sort()
 102
 103
 104 class StructTypePrettyPrinter:
 105     """Pretty-print an object of type struct type"""
 106
 107     def __init__(self, val):
 108         self.val = val
 109
 110     def to_string(self):
 111         fields = []
 112         fields.append("pointer_type = %s" % self.val['pointer_type'])
 113         fields.append("reference_type = %s" % self.val['reference_type'])
 114         fields.append("chain = %s" % self.val['reference_type'])
 115         fields.append("instance_flags = %s"
 116                       % TypeFlagsPrinter(self.val['m_instance_flags']))
 117         fields.append("length = %d" % self.val['length'])
 118         fields.append("main_type = %s" % self.val['main_type'])
 119         return "\n{" + ",\n ".join(fields) + "}"
 120
 121
 122 class StructMainTypePrettyPrinter:
 123     """Pretty-print an objet of type main_type"""
 124
 125     def __init__(self, val):
 126         self.val = val
 127
 128     def flags_to_string(self):
 129         """struct main_type contains a series of components that
 130         are one-bit ints whose name start with "flag_".  For instance:
 131         flag_unsigned, flag_stub, etc.  In essence, these components are
 132         really boolean flags, and this method prints a short synthetic
 133         version of the value of all these flags.  For instance, if
 134         flag_unsigned and flag_static are the only components set to 1,
 135         this function will return "unsigned|static".
 136         """
 137         fields = [field.name.replace("flag_", "")
 138                   for field in self.val.type.fields()
 139                   if field.name.startswith("flag_") and self.val[field.name]]
 140         return "|".join(fields)
 141
 142     def owner_to_string(self):
 143         """Return an image of component "owner".
 144         """
 145         if self.val['flag_objfile_owned'] != 0:
 146             return "%s (objfile)" % self.val['owner']['objfile']
 147         else:
 148             return "%s (gdbarch)" % self.val['owner']['gdbarch']
 149
 150     def struct_field_location_img(self, field_val):
 151         """Return an image of the loc component inside the given field
 152         gdb.Value.
 153         """
 154         loc_val = field_val['loc']
 155         loc_kind = str(field_val['loc_kind'])
 156         if loc_kind == "FIELD_LOC_KIND_BITPOS":
 157             return 'bitpos = %d' % loc_val['bitpos']
 158         elif loc_kind == "FIELD_LOC_KIND_ENUMVAL":
 159             return 'enumval = %d' % loc_val['enumval']
 160         elif loc_kind == "FIELD_LOC_KIND_PHYSADDR":
 161             return 'physaddr = 0x%x' % loc_val['physaddr']
 162         elif loc_kind == "FIELD_LOC_KIND_PHYSNAME":
 163             return 'physname = %s' % loc_val['physname']
 164         elif loc_kind == "FIELD_LOC_KIND_DWARF_BLOCK":
 165             return 'dwarf_block = %s' % loc_val['dwarf_block']
 166         else:
 167             return 'loc = ??? (unsupported loc_kind value)'
 168
 169     def struct_field_img(self, fieldno):
 170         """Return an image of the main_type field number FIELDNO.
 171         """
 172         f = self.val['flds_bnds']['fields'][fieldno]
 173         label = "flds_bnds.fields[%d]:" % fieldno
 174         if f['artificial']:
 175             label += " (artificial)"
 176         fields = []
 177         fields.append("name = %s" % f['name'])
 178         fields.append("type = %s" % f['type'])
 179         fields.append("loc_kind = %s" % f['loc_kind'])
 180         fields.append("bitsize = %d" % f['bitsize'])
 181         fields.append(self.struct_field_location_img(f))
 182         return label + "\n" + "  {" + ",\n   ".join(fields) + "}"
 183
 184     def bound_img(self, bound_name):
 185         """Return an image of the given main_type's bound."""
 186         b = self.val['flds_bnds']['bounds'].dereference()[bound_name]
 187         bnd_kind = str(b['kind'])
 188         if bnd_kind == 'PROP_CONST':
 189             return str(b['data']['const_val'])
 190         elif bnd_kind == 'PROP_UNDEFINED':
 191             return '(undefined)'
 192         else:
 193             info = [bnd_kind]
 194             if bound_name == 'high' and b['flag_upper_bound_is_count']:
 195                 info.append('upper_bound_is_count')
 196             return '{} ({})'.format(str(b['data']['baton']), ','.join(info))
 197
 198     def bounds_img(self):
 199         """Return an image of the main_type bounds.
 200         """
 201         b = self.val['flds_bnds']['bounds'].dereference()
 202         low = self.bound_img('low')
 203         high = self.bound_img('high')
 204
 205         img = "flds_bnds.bounds = {%s, %s}" % (low, high)
 206         if b['flag_bound_evaluated']:
 207             img += ' [evaluated]'
 208         return img
 209
 210     def type_specific_img(self):
 211         """Return a string image of the main_type type_specific union.
 212         Only the relevant component of that union is printed (based on
 213         the value of the type_specific_kind field.
 214         """
 215         type_specific_kind = str(self.val['type_specific_field'])
 216         type_specific = self.val['type_specific']
 217         if type_specific_kind == "TYPE_SPECIFIC_NONE":
 218             img = 'type_specific_field = %s' % type_specific_kind
 219         elif type_specific_kind == "TYPE_SPECIFIC_CPLUS_STUFF":
 220             img = "cplus_stuff = %s" % type_specific['cplus_stuff']
 221         elif type_specific_kind == "TYPE_SPECIFIC_GNAT_STUFF":
 222             img = ("gnat_stuff = {descriptive_type = %s}"
 223                    % type_specific['gnat_stuff']['descriptive_type'])
 224         elif type_specific_kind == "TYPE_SPECIFIC_FLOATFORMAT":
 225             img = "floatformat[0..1] = %s" % type_specific['floatformat']
 226         elif type_specific_kind == "TYPE_SPECIFIC_FUNC":
 227             img = ("calling_convention = %d"
 228                    % type_specific['func_stuff']['calling_convention'])
 229             # tail_call_list is not printed.
 230         elif type_specific_kind == "TYPE_SPECIFIC_SELF_TYPE":
 231             img = "self_type = %s" % type_specific['self_type']
 232         elif type_specific_kind == "TYPE_SPECIFIC_FIXED_POINT":
 233             # The scaling factor is an opaque structure, so we cannot
 234             # decode its value from Python (not without insider knowledge).
 235             img = ('scaling_factor: <opaque> (call __gmpz_dump with '
 236                    ' _mp_num and _mp_den fields if needed)')
 237         else:
 238             img = ("type_specific = ??? (unknown type_secific_kind: %s)"
 239                    % type_specific_kind)
 240         return img
 241
 242     def to_string(self):
 243         """Return a pretty-printed image of our main_type.
 244         """
 245         fields = []
 246         fields.append("name = %s" % self.val['name'])
 247         fields.append("code = %s" % self.val['code'])
 248         fields.append("flags = [%s]" % self.flags_to_string())
 249         fields.append("owner = %s" % self.owner_to_string())
 250         fields.append("target_type = %s" % self.val['target_type'])
 251         if self.val['nfields'] > 0:
 252             for fieldno in range(self.val['nfields']):
 253                 fields.append(self.struct_field_img(fieldno))
 254         if self.val['code'] == gdb.TYPE_CODE_RANGE:
 255             fields.append(self.bounds_img())
 256         fields.append(self.type_specific_img())
 257
 258         return "\n{" + ",\n ".join(fields) + "}"
 259
 260
 261 class CoreAddrPrettyPrinter:
 262     """Print CORE_ADDR values as hex."""
 263
 264     def __init__(self, val):
 265         self._val = val
 266
 267     def to_string(self):
 268         return hex(int(self._val))
 269
 270
 271 def type_lookup_function(val):
 272     """A routine that returns the correct pretty printer for VAL
 273     if appropriate.  Returns None otherwise.
 274     """
 275     if val.type.tag == "type":
 276         return StructTypePrettyPrinter(val)
 277     elif val.type.tag == "main_type":
 278         return StructMainTypePrettyPrinter(val)
 279     elif val.type.name == 'CORE_ADDR':
 280         return CoreAddrPrettyPrinter(val)
 281     return None
 282
 283
 284 def register_pretty_printer(objfile):
 285     """A routine to register a pretty-printer against the given OBJFILE.
 286     """
 287     objfile.pretty_printers.append(type_lookup_function)
 288
 289
 290 if __name__ == "__main__":
 291     if gdb.current_objfile() is not None:
 292         # This is the case where this script is being "auto-loaded"
 293         # for a given objfile.  Register the pretty-printer for that
 294         # objfile.
 295         register_pretty_printer(gdb.current_objfile())
 296     else:
 297         # We need to locate the objfile corresponding to the GDB
 298         # executable, and register the pretty-printer for that objfile.
 299         # FIXME: The condition used to match the objfile is too simplistic
 300         # and will not work on Windows.
 301         for objfile in gdb.objfiles():
 302             if os.path.basename(objfile.filename) == "gdb":
 303                 objfile.pretty_printers.append(type_lookup_function)