gdb/gdb-gdb.py.in

   1 # Copyright (C) 2009-2021 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 = [
  77                 flag.short_name for flag in TYPE_FLAGS if self.val & flag.value
  78             ]
  79         else:
  80             flag_list = ["???"]
  81         return "0x%x [%s]" % (self.val, "|".join(flag_list))
  82
  83     def init_TYPE_FLAGS(self):
  84         """Initialize the TYPE_FLAGS global as a list of TypeFlag objects.
  85         This operation requires the search of a couple of enumeration types.
  86         If not found, a warning is printed on stdout, and TYPE_FLAGS is
  87         set to the empty list.
  88
  89         The resulting list is sorted by increasing value, to facilitate
  90         printing of the list of flags used in an instance_flags value.
  91         """
  92         global TYPE_FLAGS
  93         TYPE_FLAGS = []
  94         try:
  95             iflags = gdb.lookup_type("enum type_instance_flag_value")
  96         except:
  97             print("Warning: Cannot find enum type_instance_flag_value type.")
  98             print("         `struct type' pretty-printer will be degraded")
  99             return
 100         TYPE_FLAGS = [TypeFlag(field.name, field.enumval) 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(
 116             "instance_flags = %s" % TypeFlagsPrinter(self.val["m_instance_flags"])
 117         )
 118         fields.append("length = %d" % self.val["length"])
 119         fields.append("main_type = %s" % self.val["main_type"])
 120         return "\n{" + ",\n ".join(fields) + "}"
 121
 122
 123 class StructMainTypePrettyPrinter:
 124     """Pretty-print an objet of type main_type"""
 125
 126     def __init__(self, val):
 127         self.val = val
 128
 129     def flags_to_string(self):
 130         """struct main_type contains a series of components that
 131         are one-bit ints whose name start with "flag_".  For instance:
 132         flag_unsigned, flag_stub, etc.  In essence, these components are
 133         really boolean flags, and this method prints a short synthetic
 134         version of the value of all these flags.  For instance, if
 135         flag_unsigned and flag_static are the only components set to 1,
 136         this function will return "unsigned|static".
 137         """
 138         fields = [
 139             field.name.replace("flag_", "")
 140             for field in self.val.type.fields()
 141             if field.name.startswith("flag_") and self.val[field.name]
 142         ]
 143         return "|".join(fields)
 144
 145     def owner_to_string(self):
 146         """Return an image of component "owner"."""
 147         if self.val["m_flag_objfile_owned"] != 0:
 148             return "%s (objfile)" % self.val["m_owner"]["objfile"]
 149         else:
 150             return "%s (gdbarch)" % self.val["m_owner"]["gdbarch"]
 151
 152     def struct_field_location_img(self, field_val):
 153         """Return an image of the loc component inside the given field
 154         gdb.Value.
 155         """
 156         loc_val = field_val["loc"]
 157         loc_kind = str(field_val["loc_kind"])
 158         if loc_kind == "FIELD_LOC_KIND_BITPOS":
 159             return "bitpos = %d" % loc_val["bitpos"]
 160         elif loc_kind == "FIELD_LOC_KIND_ENUMVAL":
 161             return "enumval = %d" % loc_val["enumval"]
 162         elif loc_kind == "FIELD_LOC_KIND_PHYSADDR":
 163             return "physaddr = 0x%x" % loc_val["physaddr"]
 164         elif loc_kind == "FIELD_LOC_KIND_PHYSNAME":
 165             return "physname = %s" % loc_val["physname"]
 166         elif loc_kind == "FIELD_LOC_KIND_DWARF_BLOCK":
 167             return "dwarf_block = %s" % loc_val["dwarf_block"]
 168         else:
 169             return "loc = ??? (unsupported loc_kind value)"
 170
 171     def struct_field_img(self, fieldno):
 172         """Return an image of the main_type field number FIELDNO."""
 173         f = self.val["flds_bnds"]["fields"][fieldno]
 174         label = "flds_bnds.fields[%d]:" % fieldno
 175         if f["artificial"]:
 176             label += " (artificial)"
 177         fields = []
 178         fields.append("name = %s" % f["name"])
 179         fields.append("type = %s" % f["m_type"])
 180         fields.append("loc_kind = %s" % f["loc_kind"])
 181         fields.append("bitsize = %d" % f["bitsize"])
 182         fields.append(self.struct_field_location_img(f))
 183         return label + "\n" + "  {" + ",\n   ".join(fields) + "}"
 184
 185     def bound_img(self, bound_name):
 186         """Return an image of the given main_type's bound."""
 187         bounds = self.val["flds_bnds"]["bounds"].dereference()
 188         b = bounds[bound_name]
 189         bnd_kind = str(b["m_kind"])
 190         if bnd_kind == "PROP_CONST":
 191             return str(b["m_data"]["const_val"])
 192         elif bnd_kind == "PROP_UNDEFINED":
 193             return "(undefined)"
 194         else:
 195             info = [bnd_kind]
 196             if bound_name == "high" and bounds["flag_upper_bound_is_count"]:
 197                 info.append("upper_bound_is_count")
 198             return "{} ({})".format(str(b["m_data"]["baton"]), ",".join(info))
 199
 200     def bounds_img(self):
 201         """Return an image of the main_type bounds."""
 202         b = self.val["flds_bnds"]["bounds"].dereference()
 203         low = self.bound_img("low")
 204         high = self.bound_img("high")
 205
 206         img = "flds_bnds.bounds = {%s, %s}" % (low, high)
 207         if b["flag_bound_evaluated"]:
 208             img += " [evaluated]"
 209         return img
 210
 211     def type_specific_img(self):
 212         """Return a string image of the main_type type_specific union.
 213         Only the relevant component of that union is printed (based on
 214         the value of the type_specific_kind field.
 215         """
 216         type_specific_kind = str(self.val["type_specific_field"])
 217         type_specific = self.val["type_specific"]
 218         if type_specific_kind == "TYPE_SPECIFIC_NONE":
 219             img = "type_specific_field = %s" % type_specific_kind
 220         elif type_specific_kind == "TYPE_SPECIFIC_CPLUS_STUFF":
 221             img = "cplus_stuff = %s" % type_specific["cplus_stuff"]
 222         elif type_specific_kind == "TYPE_SPECIFIC_GNAT_STUFF":
 223             img = (
 224                 "gnat_stuff = {descriptive_type = %s}"
 225                 % type_specific["gnat_stuff"]["descriptive_type"]
 226             )
 227         elif type_specific_kind == "TYPE_SPECIFIC_FLOATFORMAT":
 228             img = "floatformat[0..1] = %s" % type_specific["floatformat"]
 229         elif type_specific_kind == "TYPE_SPECIFIC_FUNC":
 230             img = (
 231                 "calling_convention = %d"
 232                 % type_specific["func_stuff"]["calling_convention"]
 233             )
 234             # tail_call_list is not printed.
 235         elif type_specific_kind == "TYPE_SPECIFIC_SELF_TYPE":
 236             img = "self_type = %s" % type_specific["self_type"]
 237         elif type_specific_kind == "TYPE_SPECIFIC_FIXED_POINT":
 238             # The scaling factor is an opaque structure, so we cannot
 239             # decode its value from Python (not without insider knowledge).
 240             img = (
 241                 "scaling_factor: <opaque> (call __gmpz_dump with "
 242                 " _mp_num and _mp_den fields if needed)"
 243             )
 244         else:
 245             img = (
 246                 "type_specific = ??? (unknown type_secific_kind: %s)"
 247                 % type_specific_kind
 248             )
 249         return img
 250
 251     def to_string(self):
 252         """Return a pretty-printed image of our main_type."""
 253         fields = []
 254         fields.append("name = %s" % self.val["name"])
 255         fields.append("code = %s" % self.val["code"])
 256         fields.append("flags = [%s]" % self.flags_to_string())
 257         fields.append("owner = %s" % self.owner_to_string())
 258         fields.append("target_type = %s" % self.val["target_type"])
 259         if self.val["nfields"] > 0:
 260             for fieldno in range(self.val["nfields"]):
 261                 fields.append(self.struct_field_img(fieldno))
 262         if self.val["code"] == gdb.TYPE_CODE_RANGE:
 263             fields.append(self.bounds_img())
 264         fields.append(self.type_specific_img())
 265
 266         return "\n{" + ",\n ".join(fields) + "}"
 267
 268
 269 class CoreAddrPrettyPrinter:
 270     """Print CORE_ADDR values as hex."""
 271
 272     def __init__(self, val):
 273         self._val = val
 274
 275     def to_string(self):
 276         return hex(int(self._val))
 277
 278
 279 class IntrusiveListPrinter:
 280     """Print a struct intrusive_list."""
 281
 282     def __init__(self, val):
 283         self._val = val
 284
 285         # Type of linked items.
 286         self._item_type = self._val.type.template_argument(0)
 287         self._node_ptr_type = gdb.lookup_type(
 288             "intrusive_list_node<{}>".format(self._item_type.tag)
 289         ).pointer()
 290
 291         # Type of value -> node converter.
 292         self._conv_type = self._val.type.template_argument(1)
 293
 294         if self._uses_member_node():
 295             # The second template argument of intrusive_member_node is a member
 296             # pointer value.  Its value is the offset of the node member in the
 297             # enclosing type.
 298             member_node_ptr = self._conv_type.template_argument(1)
 299             member_node_ptr = member_node_ptr.cast(gdb.lookup_type("int"))
 300             self._member_node_offset = int(member_node_ptr)
 301
 302             # This is only needed in _as_node_ptr if using a member node.  Look it
 303             # up here so we only do it once.
 304             self._char_ptr_type = gdb.lookup_type("char").pointer()
 305
 306     def display_hint(self):
 307         return "array"
 308
 309     def _uses_member_node(self):
 310         """Return True if the list items use a node as a member, False if
 311         they use a node as a base class.
 312         """
 313
 314         if self._conv_type.name.startswith("intrusive_member_node<"):
 315             return True
 316         elif self._conv_type.name.startswith("intrusive_base_node<"):
 317             return False
 318         else:
 319             raise RuntimeError(
 320                 "Unexpected intrusive_list value -> node converter type: {}".format(
 321                     self._conv_type.name
 322                 )
 323             )
 324
 325     def to_string(self):
 326         s = "intrusive list of {}".format(self._item_type)
 327
 328         if self._uses_member_node():
 329             node_member = self._conv_type.template_argument(1)
 330             s += ", linked through {}".format(node_member)
 331
 332         return s
 333
 334     def _as_node_ptr(self, elem_ptr):
 335         """Given ELEM_PTR, a pointer to a list element, return a pointer to the
 336         corresponding intrusive_list_node.
 337         """
 338
 339         assert elem_ptr.type.code == gdb.TYPE_CODE_PTR
 340
 341         if self._uses_member_node():
 342             # Node as a member: add the member node offset from to the element's
 343             # address to get the member node's address.
 344             elem_char_ptr = elem_ptr.cast(self._char_ptr_type)
 345             node_char_ptr = elem_char_ptr + self._member_node_offset
 346             return node_char_ptr.cast(self._node_ptr_type)
 347         else:
 348             # Node as a base: just casting from node pointer to item pointer
 349             # will adjust the pointer value.
 350             return elem_ptr.cast(self._node_ptr_type)
 351
 352     def _children_generator(self):
 353         """Generator that yields one tuple per list item."""
 354
 355         elem_ptr = self._val["m_front"]
 356         idx = 0
 357         while elem_ptr != 0:
 358             yield (str(idx), elem_ptr.dereference())
 359             node_ptr = self._as_node_ptr(elem_ptr)
 360             elem_ptr = node_ptr["next"]
 361             idx += 1
 362
 363     def children(self):
 364         return self._children_generator()
 365
 366
 367 def type_lookup_function(val):
 368     """A routine that returns the correct pretty printer for VAL
 369     if appropriate.  Returns None otherwise.
 370     """
 371     tag = val.type.tag
 372     name = val.type.name
 373     if tag == "type":
 374         return StructTypePrettyPrinter(val)
 375     elif tag == "main_type":
 376         return StructMainTypePrettyPrinter(val)
 377     elif name == "CORE_ADDR":
 378         return CoreAddrPrettyPrinter(val)
 379     elif tag is not None and tag.startswith("intrusive_list<"):
 380         return IntrusiveListPrinter(val)
 381     return None
 382
 383
 384 def register_pretty_printer(objfile):
 385     """A routine to register a pretty-printer against the given OBJFILE."""
 386     objfile.pretty_printers.append(type_lookup_function)
 387
 388
 389 if __name__ == "__main__":
 390     if gdb.current_objfile() is not None:
 391         # This is the case where this script is being "auto-loaded"
 392         # for a given objfile.  Register the pretty-printer for that
 393         # objfile.
 394         register_pretty_printer(gdb.current_objfile())
 395     else:
 396         # We need to locate the objfile corresponding to the GDB
 397         # executable, and register the pretty-printer for that objfile.
 398         # FIXME: The condition used to match the objfile is too simplistic
 399         # and will not work on Windows.
 400         for objfile in gdb.objfiles():
 401             if os.path.basename(objfile.filename) == "gdb":
 402                 objfile.pretty_printers.append(type_lookup_function)