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# Copyright (C) 2009-2021 Free Software Foundation, Inc.
# This file is part of GDB.
# 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
# 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 <>.
import gdb
import os.path
class TypeFlag:
"""A class that allows us to store a flag name, its short name,
and its value.
In the GDB sources, struct type has a component called instance_flags
in which the value is the addition of various flags. These flags are
defined by the enumerates type_instance_flag_value. This class helps us
recreate a list with all these flags that is easy to manipulate and sort.
Because all flag names start with TYPE_INSTANCE_FLAG_, a short_name
attribute is provided that strips this prefix.
name: The enumeration name (eg: "TYPE_INSTANCE_FLAG_CONST").
value: The associated value.
short_name: The enumeration name, with the suffix stripped.
def __init__(self, name, value): = name
self.value = value
self.short_name = name.replace("TYPE_INSTANCE_FLAG_", "")
def __lt__(self, other):
"""Sort by value order."""
return self.value < other.value
# A list of all existing TYPE_INSTANCE_FLAGS_* enumerations,
# stored as TypeFlags objects. Lazy-initialized.
class TypeFlagsPrinter:
"""A class that prints a decoded form of an instance_flags value.
This class uses a global named TYPE_FLAGS, which is a list of
all defined TypeFlag values. Using a global allows us to compute
this list only once.
This class relies on a couple of enumeration types being defined.
If not, then printing of the instance_flag is going to be degraded,
but it's not a fatal error.
def __init__(self, val):
self.val = val
def __str__(self):
if TYPE_FLAGS is None:
if not self.val:
return "0"
flag_list = [
flag.short_name for flag in TYPE_FLAGS if self.val & flag.value
flag_list = ["???"]
return "0x%x [%s]" % (self.val, "|".join(flag_list))
def init_TYPE_FLAGS(self):
"""Initialize the TYPE_FLAGS global as a list of TypeFlag objects.
This operation requires the search of a couple of enumeration types.
If not found, a warning is printed on stdout, and TYPE_FLAGS is
set to the empty list.
The resulting list is sorted by increasing value, to facilitate
printing of the list of flags used in an instance_flags value.
iflags = gdb.lookup_type("enum type_instance_flag_value")
print("Warning: Cannot find enum type_instance_flag_value type.")
print(" `struct type' pretty-printer will be degraded")
TYPE_FLAGS = [TypeFlag(, field.enumval) for field in iflags.fields()]
class StructTypePrettyPrinter:
"""Pretty-print an object of type struct type"""
def __init__(self, val):
self.val = val
def to_string(self):
fields = []
fields.append("pointer_type = %s" % self.val["pointer_type"])
fields.append("reference_type = %s" % self.val["reference_type"])
fields.append("chain = %s" % self.val["reference_type"])
"instance_flags = %s" % TypeFlagsPrinter(self.val["m_instance_flags"])
fields.append("length = %d" % self.val["length"])
fields.append("main_type = %s" % self.val["main_type"])
return "\n{" + ",\n ".join(fields) + "}"
class StructMainTypePrettyPrinter:
"""Pretty-print an objet of type main_type"""
def __init__(self, val):
self.val = val
def flags_to_string(self):
"""struct main_type contains a series of components that
are one-bit ints whose name start with "flag_". For instance:
flag_unsigned, flag_stub, etc. In essence, these components are
really boolean flags, and this method prints a short synthetic
version of the value of all these flags. For instance, if
flag_unsigned and flag_static are the only components set to 1,
this function will return "unsigned|static".
fields = ["flag_", "")
for field in self.val.type.fields()
if"flag_") and self.val[]
return "|".join(fields)
def owner_to_string(self):
"""Return an image of component "owner"."""
if self.val["m_flag_objfile_owned"] != 0:
return "%s (objfile)" % self.val["m_owner"]["objfile"]
return "%s (gdbarch)" % self.val["m_owner"]["gdbarch"]
def struct_field_location_img(self, field_val):
"""Return an image of the loc component inside the given field
loc_val = field_val["loc"]
loc_kind = str(field_val["loc_kind"])
if loc_kind == "FIELD_LOC_KIND_BITPOS":
return "bitpos = %d" % loc_val["bitpos"]
elif loc_kind == "FIELD_LOC_KIND_ENUMVAL":
return "enumval = %d" % loc_val["enumval"]
elif loc_kind == "FIELD_LOC_KIND_PHYSADDR":
return "physaddr = 0x%x" % loc_val["physaddr"]
elif loc_kind == "FIELD_LOC_KIND_PHYSNAME":
return "physname = %s" % loc_val["physname"]
elif loc_kind == "FIELD_LOC_KIND_DWARF_BLOCK":
return "dwarf_block = %s" % loc_val["dwarf_block"]
return "loc = ??? (unsupported loc_kind value)"
def struct_field_img(self, fieldno):
"""Return an image of the main_type field number FIELDNO."""
f = self.val["flds_bnds"]["fields"][fieldno]
label = "flds_bnds.fields[%d]:" % fieldno
if f["artificial"]:
label += " (artificial)"
fields = []
fields.append("name = %s" % f["name"])
fields.append("type = %s" % f["m_type"])
fields.append("loc_kind = %s" % f["loc_kind"])
fields.append("bitsize = %d" % f["bitsize"])
return label + "\n" + " {" + ",\n ".join(fields) + "}"
def bound_img(self, bound_name):
"""Return an image of the given main_type's bound."""
bounds = self.val["flds_bnds"]["bounds"].dereference()
b = bounds[bound_name]
bnd_kind = str(b["m_kind"])
if bnd_kind == "PROP_CONST":
return str(b["m_data"]["const_val"])
elif bnd_kind == "PROP_UNDEFINED":
return "(undefined)"
info = [bnd_kind]
if bound_name == "high" and bounds["flag_upper_bound_is_count"]:
return "{} ({})".format(str(b["m_data"]["baton"]), ",".join(info))
def bounds_img(self):
"""Return an image of the main_type bounds."""
b = self.val["flds_bnds"]["bounds"].dereference()
low = self.bound_img("low")
high = self.bound_img("high")
img = "flds_bnds.bounds = {%s, %s}" % (low, high)
if b["flag_bound_evaluated"]:
img += " [evaluated]"
return img
def type_specific_img(self):
"""Return a string image of the main_type type_specific union.
Only the relevant component of that union is printed (based on
the value of the type_specific_kind field.
type_specific_kind = str(self.val["type_specific_field"])
type_specific = self.val["type_specific"]
if type_specific_kind == "TYPE_SPECIFIC_NONE":
img = "type_specific_field = %s" % type_specific_kind
elif type_specific_kind == "TYPE_SPECIFIC_CPLUS_STUFF":
img = "cplus_stuff = %s" % type_specific["cplus_stuff"]
elif type_specific_kind == "TYPE_SPECIFIC_GNAT_STUFF":
img = (
"gnat_stuff = {descriptive_type = %s}"
% type_specific["gnat_stuff"]["descriptive_type"]
elif type_specific_kind == "TYPE_SPECIFIC_FLOATFORMAT":
img = "floatformat[0..1] = %s" % type_specific["floatformat"]
elif type_specific_kind == "TYPE_SPECIFIC_FUNC":
img = (
"calling_convention = %d"
% type_specific["func_stuff"]["calling_convention"]
# tail_call_list is not printed.
elif type_specific_kind == "TYPE_SPECIFIC_SELF_TYPE":
img = "self_type = %s" % type_specific["self_type"]
elif type_specific_kind == "TYPE_SPECIFIC_FIXED_POINT":
# The scaling factor is an opaque structure, so we cannot
# decode its value from Python (not without insider knowledge).
img = (
"scaling_factor: <opaque> (call __gmpz_dump with "
" _mp_num and _mp_den fields if needed)"
img = (
"type_specific = ??? (unknown type_secific_kind: %s)"
% type_specific_kind
return img
def to_string(self):
"""Return a pretty-printed image of our main_type."""
fields = []
fields.append("name = %s" % self.val["name"])
fields.append("code = %s" % self.val["code"])
fields.append("flags = [%s]" % self.flags_to_string())
fields.append("owner = %s" % self.owner_to_string())
fields.append("target_type = %s" % self.val["target_type"])
if self.val["nfields"] > 0:
for fieldno in range(self.val["nfields"]):
if self.val["code"] == gdb.TYPE_CODE_RANGE:
return "\n{" + ",\n ".join(fields) + "}"
class CoreAddrPrettyPrinter:
"""Print CORE_ADDR values as hex."""
def __init__(self, val):
self._val = val
def to_string(self):
return hex(int(self._val))
class IntrusiveListPrinter:
"""Print a struct intrusive_list."""
def __init__(self, val):
self._val = val
# Type of linked items.
self._item_type = self._val.type.template_argument(0)
self._node_ptr_type = gdb.lookup_type(
# Type of value -> node converter.
self._conv_type = self._val.type.template_argument(1)
if self._uses_member_node():
# The second template argument of intrusive_member_node is a member
# pointer value. Its value is the offset of the node member in the
# enclosing type.
member_node_ptr = self._conv_type.template_argument(1)
member_node_ptr = member_node_ptr.cast(gdb.lookup_type("int"))
self._member_node_offset = int(member_node_ptr)
# This is only needed in _as_node_ptr if using a member node. Look it
# up here so we only do it once.
self._char_ptr_type = gdb.lookup_type("char").pointer()
def display_hint(self):
return "array"
def _uses_member_node(self):
"""Return True if the list items use a node as a member, False if
they use a node as a base class.
return True
return False
raise RuntimeError(
"Unexpected intrusive_list value -> node converter type: {}".format(
def to_string(self):
s = "intrusive list of {}".format(self._item_type)
if self._uses_member_node():
node_member = self._conv_type.template_argument(1)
s += ", linked through {}".format(node_member)
return s
def _as_node_ptr(self, elem_ptr):
"""Given ELEM_PTR, a pointer to a list element, return a pointer to the
corresponding intrusive_list_node.
assert elem_ptr.type.code == gdb.TYPE_CODE_PTR
if self._uses_member_node():
# Node as a member: add the member node offset from to the element's
# address to get the member node's address.
elem_char_ptr = elem_ptr.cast(self._char_ptr_type)
node_char_ptr = elem_char_ptr + self._member_node_offset
return node_char_ptr.cast(self._node_ptr_type)
# Node as a base: just casting from node pointer to item pointer
# will adjust the pointer value.
return elem_ptr.cast(self._node_ptr_type)
def _children_generator(self):
"""Generator that yields one tuple per list item."""
elem_ptr = self._val["m_front"]
idx = 0
while elem_ptr != 0:
yield (str(idx), elem_ptr.dereference())
node_ptr = self._as_node_ptr(elem_ptr)
elem_ptr = node_ptr["next"]
idx += 1
def children(self):
return self._children_generator()
def type_lookup_function(val):
"""A routine that returns the correct pretty printer for VAL
if appropriate. Returns None otherwise.
tag = val.type.tag
name =
if tag == "type":
return StructTypePrettyPrinter(val)
elif tag == "main_type":
return StructMainTypePrettyPrinter(val)
elif name == "CORE_ADDR":
return CoreAddrPrettyPrinter(val)
elif tag is not None and tag.startswith("intrusive_list<"):
return IntrusiveListPrinter(val)
return None
def register_pretty_printer(objfile):
"""A routine to register a pretty-printer against the given OBJFILE."""
if __name__ == "__main__":
if gdb.current_objfile() is not None:
# This is the case where this script is being "auto-loaded"
# for a given objfile. Register the pretty-printer for that
# objfile.
# We need to locate the objfile corresponding to the GDB
# executable, and register the pretty-printer for that objfile.
# FIXME: The condition used to match the objfile is too simplistic
# and will not work on Windows.
for objfile in gdb.objfiles():
if os.path.basename(objfile.filename) == "gdb":