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      1 # Type utilities.
      2 # Copyright (C) 2010, 2011 Free Software Foundation, Inc.
      3 
      4 # This program is free software; you can redistribute it and/or modify
      5 # it under the terms of the GNU General Public License as published by
      6 # the Free Software Foundation; either version 3 of the License, or
      7 # (at your option) any later version.
      8 #
      9 # This program is distributed in the hope that it will be useful,
     10 # but WITHOUT ANY WARRANTY; without even the implied warranty of
     11 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
     12 # GNU General Public License for more details.
     13 #
     14 # You should have received a copy of the GNU General Public License
     15 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
     16 
     17 """Utilities for working with gdb.Types."""
     18 
     19 import gdb
     20 
     21 
     22 def get_basic_type(type_):
     23     """Return the "basic" type of a type.
     24 
     25     Arguments:
     26         type_: The type to reduce to its basic type.
     27 
     28     Returns:
     29         type_ with const/volatile is stripped away,
     30         and typedefs/references converted to the underlying type.
     31     """
     32 
     33     while (type_.code == gdb.TYPE_CODE_REF or
     34            type_.code == gdb.TYPE_CODE_TYPEDEF):
     35         if type_.code == gdb.TYPE_CODE_REF:
     36             type_ = type_.target()
     37         else:
     38             type_ = type_.strip_typedefs()
     39     return type_.unqualified()
     40 
     41 
     42 def has_field(type_, field):
     43     """Return True if a type has the specified field.
     44 
     45     Arguments:
     46         type_: The type to examine.
     47             It must be one of gdb.TYPE_CODE_STRUCT, gdb.TYPE_CODE_UNION.
     48         field: The name of the field to look up.
     49 
     50     Returns:
     51         True if the field is present either in type_ or any baseclass.
     52 
     53     Raises:
     54         TypeError: The type is not a struct or union.
     55     """
     56 
     57     type_ = get_basic_type(type_)
     58     if (type_.code != gdb.TYPE_CODE_STRUCT and
     59         type_.code != gdb.TYPE_CODE_UNION):
     60         raise TypeError("not a struct or union")
     61     for f in type_.fields():
     62         if f.is_base_class:
     63             if has_field(f.type, field):
     64                 return True
     65         else:
     66             # NOTE: f.name could be None
     67             if f.name == field:
     68                 return True
     69     return False
     70 
     71 
     72 def make_enum_dict(enum_type):
     73     """Return a dictionary from a program's enum type.
     74 
     75     Arguments:
     76         enum_type: The enum to compute the dictionary for.
     77 
     78     Returns:
     79         The dictionary of the enum.
     80 
     81     Raises:
     82         TypeError: The type is not an enum.
     83     """
     84 
     85     if enum_type.code != gdb.TYPE_CODE_ENUM:
     86         raise TypeError("not an enum type")
     87     enum_dict = {}
     88     for field in enum_type.fields():
     89         # The enum's value is stored in "bitpos".
     90         enum_dict[field.name] = field.bitpos
     91     return enum_dict
     92