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From: Simon Farre <simon.farre.cx@gmail.com>
To: gdb-patches@sourceware.org
Cc: tromey@adacore.com, Simon Farre <simon.farre.cx@gmail.com>
Subject: [PATCH v3] gdb/dap - dataBreakpointInfo & setDataBreakpoints
Date: Mon, 19 Jun 2023 13:47:07 +0200	[thread overview]
Message-ID: <20230619114707.70902-1-simon.farre.cx@gmail.com> (raw)

v3.
Updated outdated documentation.

Made watchpoints be set using addresses by resolving them from the
gdb.Value, as Tom pointed out in v2, this means that the watchpoints are
the equivalent of `watch -l foo`.

Added tests for data breakpoint, both for a simple struct and vars[1]
which is a std::vector<Var>. To be able to test this, I had to throw in
the gcc pretty printers file, as I had no other way (it seemed to me) to
be able to source them from the test.

Also made the watchpoint creation behave/fit in to current design.

frameId is more or less ignored in it's entirety for now as it doesn't
make much sense from a GDB perspective. I suppose one way to actually make it make
sense, would be to customize a gdb.Breakpoint (i.e. deriving from it),
that behaves both as a watchpoint *and* as a finish breakpoint; as soon
as the finish breakpoint hits, remove the watchpoint.

Ran `black` on all .py files.

Removed prior versions from commit msg, due to overhaul.
---
 gdb/python/lib/gdb/dap/breakpoint.py          |  124 +-
 gdb/python/lib/gdb/dap/events.py              |    6 +-
 gdb/python/lib/gdb/dap/varref.py              |   30 +-
 gdb/testsuite/gdb.dap/data-breakpoint.cc      |   46 +
 gdb/testsuite/gdb.dap/data-breakpoint.exp     |  215 ++
 .../gdb.dap/stdlib-pretty-printers.py         | 2351 +++++++++++++++++
 6 files changed, 2764 insertions(+), 8 deletions(-)
 create mode 100644 gdb/testsuite/gdb.dap/data-breakpoint.cc
 create mode 100644 gdb/testsuite/gdb.dap/data-breakpoint.exp
 create mode 100644 gdb/testsuite/gdb.dap/stdlib-pretty-printers.py

diff --git a/gdb/python/lib/gdb/dap/breakpoint.py b/gdb/python/lib/gdb/dap/breakpoint.py
index 20e65aa0e61..bb1134a6c52 100644
--- a/gdb/python/lib/gdb/dap/breakpoint.py
+++ b/gdb/python/lib/gdb/dap/breakpoint.py
@@ -20,7 +20,8 @@ import os
 from typing import Optional, Sequence
 
 from .server import request, capability
-from .startup import send_gdb_with_response, in_gdb_thread
+from .startup import send_gdb_with_response, in_gdb_thread, log
+from .varref import find_variable
 
 
 # Map from the breakpoint "kind" (like "function") to a second map, of
@@ -34,7 +35,7 @@ breakpoint_map = {}
 @in_gdb_thread
 def breakpoint_descriptor(bp):
     "Return the Breakpoint object descriptor given a gdb Breakpoint."
-    if bp.locations:
+    if bp.location is not None and len(bp.locations) > 0:
         # Just choose the first location, because DAP doesn't allow
         # multiple locations.  See
         # https://github.com/microsoft/debug-adapter-protocol/issues/13
@@ -56,6 +57,11 @@ def breakpoint_descriptor(bp):
         if path is not None:
             result["source"]["path"] = path
         return result
+    elif bp.expression is not None:
+        return {
+            "id": bp.number,
+            "verified": True,
+        }
     else:
         return {
             "id": bp.number,
@@ -248,3 +254,117 @@ def set_exception_breakpoints(
     return {
         "breakpoints": result,
     }
+
+
+def _info_not_available(desc):
+    return {"dataId": None, "description": f"{desc}", "accessTypes": None}
+
+
+@in_gdb_thread
+def _databreakpoint_info(
+    name: str, variablesReference: Optional[int] = None, frameId: Optional[int] = None
+):
+
+    if variablesReference is not None:
+        variable = None
+        # Resolve variable expression until find_variable throws
+        try:
+            variable = find_variable(variablesReference)
+        except Exception as vr_not_found:
+            return _info_not_available(vr_not_found)
+
+        gdb_value = None
+        try:
+            gdb_value = variable.try_find_member(name)
+        except gdb.error as value_not_found:
+            return _info_not_available(value_not_found)
+
+        if gdb_value.address is None:
+            return _info_not_available("Could not take address of value")
+
+        dataId = hex(int(gdb_value.address))
+
+        return {
+            "dataId": dataId,
+            "description": f"{name} @ {dataId}",
+            "accessTypes": ["read", "write", "readWrite"],
+        }
+    elif variablesReference is None:
+        try:
+            v = gdb.parse_and_eval(name)
+            if v.address is None:
+                return _info_not_available("Could not take address of expression")
+            dataId = hex(int(v.address))
+            return {
+                "dataId": dataId,
+                "description": f"{v.type} @ {dataId}",
+                "accessTypes": ["read", "write", "readWrite"],
+            }
+        except Exception as parse_ex:
+            return _info_not_available(f"Can not find {name} ({parse_ex})")
+
+    return _info_not_available(f"Can not find {name}")
+
+
+@capability("supportsDataBreakpoints")
+@request("dataBreakpointInfo")
+def data_breakpoint_info(
+    *,
+    name: str,
+    variablesReference: Optional[int] = None,
+    frameId: Optional[int] = None,
+    **args,
+):
+    result = send_gdb_with_response(
+        lambda: _databreakpoint_info(name, variablesReference, frameId)
+    )
+    return result
+
+
+def _sanitize_wp_input(breakpoints: Sequence) -> Sequence:
+    """Sanitize input so that it plays well with current design."""
+    res = []
+    for wp in breakpoints:
+        obj = {}
+        obj["condition"] = wp.get("condition")
+        obj["hitCondition"] = wp.get("hitCondition")
+        obj["accessType"] = wp.get("accessType")
+        obj["dataId"] = wp.get("dataId")
+        res.append(obj)
+    return res
+
+
+def _wp_type(type: str):
+    if type == "read":
+        return gdb.WP_READ
+    if type == "write":
+        return gdb.WP_WRITE
+    if type == "readWrite":
+        return gdb.WP_ACCESS
+    raise gdb.GdbError("Erroneous watchpoint type")
+
+
+@in_gdb_thread
+def _create_watchpoints(dataId, accessType, enabled=True):
+    wp = gdb.Breakpoint(
+        spec=f"*{dataId}", type=gdb.BP_WATCHPOINT, wp_class=_wp_type(accessType)
+    )
+    wp.enabled = enabled
+    return wp
+
+
+@in_gdb_thread
+def _set_data_breakpoints(breakpoints: Sequence):
+    return _set_breakpoints_callback("watchpoints", breakpoints, _create_watchpoints)
+
+
+@request("setDataBreakpoints")
+@capability("supportsDataBreakpoints")
+@capability("supportsHitConditionalBreakpoints")
+@capability("supportsConditionalBreakpoints")
+def set_databreakpoints(*, breakpoints: Sequence = (), **args):
+    wps = _sanitize_wp_input(breakpoints=breakpoints)
+    result = send_gdb_with_response(lambda: _set_data_breakpoints(wps))
+    return {
+        "breakpoints": result,
+    }
diff --git a/gdb/python/lib/gdb/dap/events.py b/gdb/python/lib/gdb/dap/events.py
index d9ae603dfa4..8fbf1f09891 100644
--- a/gdb/python/lib/gdb/dap/events.py
+++ b/gdb/python/lib/gdb/dap/events.py
@@ -101,6 +101,7 @@ class StopKinds(enum.Enum):
     # The values here are chosen to follow the DAP spec.
     STEP = "step"
     BREAKPOINT = "breakpoint"
+    DATABREAKPOINT = "data breakpoint"
     PAUSE = "pause"
     EXCEPTION = "exception"
 
@@ -144,7 +145,10 @@ def _on_stop(event):
     }
     if isinstance(event, gdb.BreakpointEvent):
         # Ignore the expected stop, we hit a breakpoint instead.
-        _expected_stop = StopKinds.BREAKPOINT
+        if event.breakpoints[0].expression:
+            _expected_stop = StopKinds.DATABREAKPOINT
+        else:
+            _expected_stop = StopKinds.BREAKPOINT
         obj["hitBreakpointIds"] = [x.number for x in event.breakpoints]
     elif _expected_stop is None:
         # FIXME what is even correct here
diff --git a/gdb/python/lib/gdb/dap/varref.py b/gdb/python/lib/gdb/dap/varref.py
index 23f18d647c3..5a49384a6b6 100644
--- a/gdb/python/lib/gdb/dap/varref.py
+++ b/gdb/python/lib/gdb/dap/varref.py
@@ -22,7 +22,6 @@ from abc import abstractmethod
 # A list of all the variable references created during this pause.
 all_variables = []
 
-
 # When the inferior is re-started, we erase all variable references.
 # See the section "Lifetime of Objects References" in the spec.
 @in_gdb_thread
@@ -101,7 +100,7 @@ class BaseReference:
         for idx in range(start, start + count):
             if self.children[idx] is None:
                 (name, value) = self.fetch_one_child(idx)
-                self.children[idx] = VariableReference(name, value)
+                self.children[idx] = VariableReference(name=name, value=value)
             result.append(self.children[idx])
         return result
 
@@ -109,13 +108,15 @@ class BaseReference:
 class VariableReference(BaseReference):
     """Concrete subclass of BaseReference that handles gdb.Value."""
 
-    def __init__(self, name, value, result_name="value"):
+    def __init__(self, name, value: gdb.Value, result_name="value"):
         """Initializer.
 
         NAME is the name of this reference, see superclass.
         VALUE is a gdb.Value that holds the value.
         RESULT_NAME can be used to change how the simple string result
-        is emitted in the result dictionary."""
+        is emitted in the result dictionary.
+        P_REF parent variableReference. Is set to -1 if parent is not
+        of VariableReference type"""
         super().__init__(name)
         self.value = value
         self.printer = gdb.printing.make_visualizer(value)
@@ -128,6 +129,22 @@ class VariableReference(BaseReference):
         else:
             self.count = -1
 
+    def try_find_member(self, name: str) -> gdb.Value:
+        type = self.value.type
+        # Non-pretty printed values more common. Search type definition first
+        for field in type.fields():
+            if field.name == name:
+                return self.value[field]
+
+        if not hasattr(self.printer, "children"):
+            raise gdb.error("Pretty printer has no children")
+
+        for (child_name, value) in self.printer.children():
+            if child_name == name:
+                return value
+
+        raise gdb.error(f"Child {name} could not be found in {self.name}")
+
     def cache_children(self):
         if self.child_cache is None:
             # This discards all laziness.  This could be improved
@@ -152,7 +169,10 @@ class VariableReference(BaseReference):
 
     def to_object(self):
         result = super().to_object()
-        result[self.result_name] = self.printer.to_string()
+
+        result[self.result_name] = (
+            f"{self.value.type}" if self.ref is not 0 else f"{self.value}"
+        )
         num_children = self.child_count()
         if num_children is not None:
             if (
diff --git a/gdb/testsuite/gdb.dap/data-breakpoint.cc b/gdb/testsuite/gdb.dap/data-breakpoint.cc
new file mode 100644
index 00000000000..7b82e013d6d
--- /dev/null
+++ b/gdb/testsuite/gdb.dap/data-breakpoint.cc
@@ -0,0 +1,46 @@
+/* Copyright 2023 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
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   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 <http://www.gnu.org/licenses/>.  */
+
+
+#include <vector>
+
+struct Var {
+  int val;
+  struct Member {
+    int val;
+  } member;
+};
+
+static Var global{.val = 10, .member = Var::Member{ .val = 20 }};
+
+int
+main (int argc, const char** argv)
+{
+  std::vector<Var> vars{};
+  vars.reserve(10); // Make sure no re-alloc
+  vars.emplace_back(Var{.val = 1, .member = Var::Member{ .val = 2 }});
+  vars.emplace_back(Var{.val = 3, .member = Var::Member{ .val = 4 }});
+  vars.emplace_back(Var{.val = 5, .member = Var::Member{ .val = 6 }});
+
+  Var var{.val = 7, .member = Var::Member{ .val = 8 }};
+  int new_val = 30;
+  int member_new_val = 40; /* PRETTY_PRINT_WP */
+  auto copy = vars[1]; /* AFTER_VARS_PP_READ */
+  var.val = new_val;
+  var.member.val = member_new_val;
+  return 0; /* AFTER_SIMPLE_WRITE */
+}
diff --git a/gdb/testsuite/gdb.dap/data-breakpoint.exp b/gdb/testsuite/gdb.dap/data-breakpoint.exp
new file mode 100644
index 00000000000..1fac0962937
--- /dev/null
+++ b/gdb/testsuite/gdb.dap/data-breakpoint.exp
@@ -0,0 +1,215 @@
+# Copyright 2022-2023 Free Software Foundation, Inc.
+
+# 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
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# 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 <http://www.gnu.org/licenses/>.
+
+# Basic DAP test.
+
+require allow_dap_tests
+
+load_lib dap-support.exp
+
+set stdlib_pp stdlib-pretty-printers.py
+set remote_python_file [gdb_remote_download host ${srcdir}/${subdir}/${stdlib_pp}]
+set sourcepp "source ${remote_python_file}"
+
+standard_testfile .cc
+set exefile $testfile
+
+if {[build_executable "failed to prepare" $exefile $srcfile {debug c++}]} {
+    return
+}
+
+if {[dap_launch $testfile] == ""} {
+    return
+}
+
+proc get_stack_frame_id { level } {
+  set args {o threadId [i 1] }
+  set bt [lindex [dap_request_and_response stackTrace $args ] 0]
+  set frame_id [dict get [lindex [dict get $bt body stackFrames] $level] id]
+  return $frame_id
+}
+
+proc get_line_of_frame { level } {
+  set bt [ dap_request_and_response stackTrace {o threadId [i 1]}]
+  set bt [lindex $bt 0]
+  set stop [dict get [lindex [dict get $bt body stackFrames] $level] line]
+  return $stop
+}
+
+proc get_variables_of { vr } {
+  set args [format {o variablesReference [i %d] } $vr]
+  set refs [dap_request_and_response variables $args ]
+  set refs [lindex $refs 0]
+
+  return [dict get $refs body variables]
+}
+
+proc get_variable_reference_for { frame_id name_ } {
+  set variables [ get_variables_of $frame_id ]
+  set result {}
+  foreach var $variables {
+    set var_name [dict get $var name]
+    if { $var_name == $name_ } {
+      set result [dict get $var variablesReference]
+    }
+  }
+  return $result
+}
+
+proc get_local_scope { frame_id } {
+  set scopes_res [dap_request_and_response scopes {o frameId [i $frame_id]} ]
+  set scopes [dict get [lindex $scopes_res 0] body scopes]
+  lassign $scopes args locals reg_scope
+  set local [dict get $locals variablesReference]
+  return $local
+}
+
+set line [gdb_get_line_number "PRETTY_PRINT_WP"]
+set obj [dap_check_request_and_response "set breakpoint by line number" \
+	     setBreakpoints \
+	     [format {o source [o path [%s]] breakpoints [a [o line [i %d]]]} \
+		  [list s $srcfile] $line]]
+set line_bpno [dap_get_breakpoint_number $obj]
+
+dap_check_request_and_response "start inferior" configurationDone
+dap_wait_for_event_and_check "inferior started" thread "body reason" started
+
+dap_wait_for_event_and_check "stopped at line breakpoint" stopped \
+    "body reason" breakpoint \
+    "body hitBreakpointIds" $line_bpno
+
+
+set frame_id [ get_stack_frame_id 0 ]
+dap_check_request_and_response "source pretty printers" evaluate \
+	{o context [s "repl"] frameId [i $frame_id] expression [s $sourcepp]}
+set register_pp_cmd "py register_libstdcxx_printers(gdb.current_objfile())"
+dap_check_request_and_response "register pretty printers" evaluate {o context [s "repl"] frameId [i $frame_id] expression [s $register_pp_cmd]}
+
+set local [ get_local_scope $frame_id ]
+
+set pretty_printed_var_ref [ get_variable_reference_for $local "vars" ]
+
+# Do nothing with this, we need GDB to retrive the children of "vars"
+set vars_members [ get_variables_of $pretty_printed_var_ref ]
+# get dataBreakpointInfo for vars[1]
+set dbi_vars_idx_1 \
+	[lindex [dap_check_request_and_response \
+		 "dataBreakpointInfo request var ref + name" \
+		 dataBreakpointInfo \
+		 {o variablesReference [i $pretty_printed_var_ref] name [s "\[1\]"] }] 0]
+
+set dataId [ dict get $dbi_vars_idx_1 body dataId ]
+
+set wp_response [lindex [dap_check_request_and_response "set read watchpoint" \
+		 	setDataBreakpoints \
+			{o breakpoints \
+			[a [o dataId [s $dataId] accessType [s "read" ] ] ] \
+			}] \
+		0 ]
+
+set after_read [gdb_get_line_number "AFTER_VARS_PP_READ"]
+
+dap_check_request_and_response "continue until watchpoint triggers" continue \
+    {o threadId [i 1]}
+
+dap_wait_for_event_and_check "stopped at read watchpoint" stopped \
+    "body reason" "data breakpoint" \
+    "body hitBreakpointIds" 2
+
+
+set stopped_line [ get_line_of_frame 0 ]
+
+gdb_assert { $stopped_line == $after_read } \
+	"Watchpoint stopped at line $stopped_line (should stop at $after_read)"
+
+# Set watchpoint for simple data type Var
+set frame_id [ get_stack_frame_id 0 ]
+
+set scopes [dap_check_request_and_response "get scopes" scopes \
+		[format {o frameId [i %d]} $frame_id]]
+set scopes [dict get [lindex $scopes 0] body scopes]
+
+lassign $scopes args scope reg_scope
+set locals [dict get $scope variablesReference]
+
+set var [ get_variable_reference_for $locals "var" ]
+
+set var_members [ get_variables_of $var ]
+
+set var_member_var_ref [ get_variable_reference_for $var "member" ]
+
+set dbi_var_member_val [lindex [dap_check_request_and_response "varRef name" \
+				 dataBreakpointInfo {o variablesReference \
+				 [i $var_member_var_ref] name [s "val"] } \
+				] 0 ]
+
+set dataId [ dict get $dbi_var_member_val body dataId ]
+
+# Same as above but without variablesReference and the full resolve symbol path
+set dbi_var_member_val [lindex [dap_check_request_and_response "name only" \
+		     dataBreakpointInfo {o name [s "var.member.val"] }] 0]
+
+set dataId [ dict get $dbi_var_member_val body dataId ]
+
+set wp_response [lindex [dap_check_request_and_response "set write watchpoint" \
+		 	setDataBreakpoints \
+			{o breakpoints \
+			[a [o dataId [s $dataId] accessType [s "write" ] ] ] \
+			}] \
+		0 ]
+
+# dataBreakpointInfo for global.member.val => dataId == None
+set dbi_global_member_val \
+	[lindex [dap_check_request_and_response \
+		 "dataBreakpointInfo dataId == None" \
+		 dataBreakpointInfo \
+		 {o frameId [i $frame_id ] name [s "global.member.val"] } \
+		 ] \
+	0 ]
+
+set null_dataId [ dict get $dbi_global_member_val body dataId ]
+gdb_assert { $null_dataId == "null" } "with frameid should return null"
+
+# dataBreakpointInfo for global.member.val without varRef|frameId
+set dbi_global_member_val \
+	[lindex [dap_check_request_and_response \
+			"dataBreakpointInfo request" \
+			dataBreakpointInfo \
+			{o name [s "global.member.val"] } \
+		] \
+	0]
+
+set dataId [ dict get $dbi_global_member_val body dataId ]
+gdb_assert { $dataId != "null" } "Should find globals"
+
+set after_write [gdb_get_line_number "AFTER_SIMPLE_WRITE"]
+
+dap_check_request_and_response "continue until simple watchpoint triggers" continue \
+    {o threadId [i 1]}
+
+dap_wait_for_event_and_check "stopped at write watchpoint" stopped \
+    "body reason" "data breakpoint" \
+    "body hitBreakpointIds" 3
+
+set bt [lindex [dap_check_request_and_response "stopped at line" stackTrace \
+		    {o threadId [i 1]}] \
+	    0]
+
+set stopped_line [dict get [lindex [dict get $bt body stackFrames] 0] line]
+
+gdb_assert { $stopped_line == $after_write } \
+	"Watchpoint stopped at line $stopped_line"
+
+dap_shutdown
diff --git a/gdb/testsuite/gdb.dap/stdlib-pretty-printers.py b/gdb/testsuite/gdb.dap/stdlib-pretty-printers.py
new file mode 100644
index 00000000000..bb06a4959ee
--- /dev/null
+++ b/gdb/testsuite/gdb.dap/stdlib-pretty-printers.py
@@ -0,0 +1,2351 @@
+# Pretty-printers for libstdc++.
+
+# Copyright (C) 2008-2022 Free Software Foundation, Inc.
+
+# 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
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# 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 <http://www.gnu.org/licenses/>.
+
+import gdb
+import itertools
+import re
+import sys, os, errno
+
+### Python 2 + Python 3 compatibility code
+
+# Resources about compatibility:
+#
+#  * <http://pythonhosted.org/six/>: Documentation of the "six" module
+
+# FIXME: The handling of e.g. std::basic_string (at least on char)
+# probably needs updating to work with Python 3's new string rules.
+#
+# In particular, Python 3 has a separate type (called byte) for
+# bytestrings, and a special b"" syntax for the byte literals; the old
+# str() type has been redefined to always store Unicode text.
+#
+# We probably can't do much about this until this GDB PR is addressed:
+# <https://sourceware.org/bugzilla/show_bug.cgi?id=17138>
+
+if sys.version_info[0] > 2:
+    ### Python 3 stuff
+    Iterator = object
+    # Python 3 folds these into the normal functions.
+    imap = map
+    izip = zip
+    # Also, int subsumes long
+    long = int
+else:
+    ### Python 2 stuff
+    class Iterator:
+        """Compatibility mixin for iterators
+
+        Instead of writing next() methods for iterators, write
+        __next__() methods and use this mixin to make them work in
+        Python 2 as well as Python 3.
+
+        Idea stolen from the "six" documentation:
+        <http://pythonhosted.org/six/#six.Iterator>
+        """
+
+        def next(self):
+            return self.__next__()
+
+    # In Python 2, we still need these from itertools
+    from itertools import imap, izip
+
+# Try to use the new-style pretty-printing if available.
+_use_gdb_pp = True
+try:
+    import gdb.printing
+except ImportError:
+    _use_gdb_pp = False
+
+# Try to install type-printers.
+_use_type_printing = False
+try:
+    import gdb.types
+    if hasattr(gdb.types, 'TypePrinter'):
+        _use_type_printing = True
+except ImportError:
+    pass
+
+# Starting with the type ORIG, search for the member type NAME.  This
+# handles searching upward through superclasses.  This is needed to
+# work around http://sourceware.org/bugzilla/show_bug.cgi?id=13615.
+def find_type(orig, name):
+    typ = orig.strip_typedefs()
+    while True:
+        # Use Type.tag to ignore cv-qualifiers.  PR 67440.
+        search = '%s::%s' % (typ.tag, name)
+        try:
+            return gdb.lookup_type(search)
+        except RuntimeError:
+            pass
+        # The type was not found, so try the superclass.  We only need
+        # to check the first superclass, so we don't bother with
+        # anything fancier here.
+        fields = typ.fields()
+        if len(fields) and fields[0].is_base_class:
+            typ = fields[0].type
+        else:
+            raise ValueError("Cannot find type %s::%s" % (str(orig), name))
+
+_versioned_namespace = '__8::'
+
+def lookup_templ_spec(templ, *args):
+    """
+    Lookup template specialization templ<args...>
+    """
+    t = '{}<{}>'.format(templ, ', '.join([str(a) for a in args]))
+    try:
+        return gdb.lookup_type(t)
+    except gdb.error as e:
+        # Type not found, try again in versioned namespace.
+        global _versioned_namespace
+        if _versioned_namespace and _versioned_namespace not in templ:
+            t = t.replace('::', '::' + _versioned_namespace, 1)
+            try:
+                return gdb.lookup_type(t)
+            except gdb.error:
+                # If that also fails, rethrow the original exception
+                pass
+        raise e
+
+# Use this to find container node types instead of find_type,
+# see https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91997 for details.
+def lookup_node_type(nodename, containertype):
+    """
+    Lookup specialization of template NODENAME corresponding to CONTAINERTYPE.
+    e.g. if NODENAME is '_List_node' and CONTAINERTYPE is std::list<int>
+    then return the type std::_List_node<int>.
+    Returns None if not found.
+    """
+    # If nodename is unqualified, assume it's in namespace std.
+    if '::' not in nodename:
+        nodename = 'std::' + nodename
+    try:
+        valtype = find_type(containertype, 'value_type')
+    except:
+        valtype = containertype.template_argument(0)
+    valtype = valtype.strip_typedefs()
+    try:
+        return lookup_templ_spec(nodename, valtype)
+    except gdb.error as e:
+        # For debug mode containers the node is in std::__cxx1998.
+        if is_member_of_namespace(nodename, 'std'):
+            if is_member_of_namespace(containertype, 'std::__cxx1998',
+                                      'std::__debug', '__gnu_debug'):
+                nodename = nodename.replace('::', '::__cxx1998::', 1)
+                try:
+                    return lookup_templ_spec(nodename, valtype)
+                except gdb.error:
+                    pass
+        return None
+
+def is_member_of_namespace(typ, *namespaces):
+    """
+    Test whether a type is a member of one of the specified namespaces.
+    The type can be specified as a string or a gdb.Type object.
+    """
+    if type(typ) is gdb.Type:
+        typ = str(typ)
+    typ = strip_versioned_namespace(typ)
+    for namespace in namespaces:
+        if typ.startswith(namespace + '::'):
+            return True
+    return False
+
+def is_specialization_of(x, template_name):
+    "Test if a type is a given template instantiation."
+    global _versioned_namespace
+    if type(x) is gdb.Type:
+        x = x.tag
+    if _versioned_namespace:
+        return re.match('^std::(%s)?%s<.*>$' % (_versioned_namespace, template_name), x) is not None
+    return re.match('^std::%s<.*>$' % template_name, x) is not None
+
+def strip_versioned_namespace(typename):
+    global _versioned_namespace
+    if _versioned_namespace:
+        return typename.replace(_versioned_namespace, '')
+    return typename
+
+def strip_inline_namespaces(type_str):
+    "Remove known inline namespaces from the canonical name of a type."
+    type_str = strip_versioned_namespace(type_str)
+    type_str = type_str.replace('std::__cxx11::', 'std::')
+    expt_ns = 'std::experimental::'
+    for lfts_ns in ('fundamentals_v1', 'fundamentals_v2'):
+        type_str = type_str.replace(expt_ns+lfts_ns+'::', expt_ns)
+    fs_ns = expt_ns + 'filesystem::'
+    type_str = type_str.replace(fs_ns+'v1::', fs_ns)
+    return type_str
+
+def get_template_arg_list(type_obj):
+    "Return a type's template arguments as a list"
+    n = 0
+    template_args = []
+    while True:
+        try:
+            template_args.append(type_obj.template_argument(n))
+        except:
+            return template_args
+        n += 1
+
+class SmartPtrIterator(Iterator):
+    "An iterator for smart pointer types with a single 'child' value"
+
+    def __init__(self, val):
+        self.val = val
+
+    def __iter__(self):
+        return self
+
+    def __next__(self):
+        if self.val is None:
+            raise StopIteration
+        self.val, val = None, self.val
+        return ('get()', val)
+
+class SharedPointerPrinter:
+    "Print a shared_ptr, weak_ptr, atomic<shared_ptr>, or atomic<weak_ptr>"
+
+    def __init__ (self, typename, val):
+        self.typename = strip_versioned_namespace(typename)
+        self.val = val
+        self.pointer = val['_M_ptr']
+
+    def children (self):
+        return SmartPtrIterator(self.pointer)
+
+    # Return the _Sp_counted_base<>* that holds the refcounts.
+    def _get_refcounts (self):
+        if self.typename == 'std::atomic':
+            # A tagged pointer is stored as uintptr_t.
+            ptr_val = self.val['_M_refcount']['_M_val']['_M_i']
+            ptr_val = ptr_val - (ptr_val % 2) # clear lock bit
+            ptr_type = find_type(self.val['_M_refcount'].type, 'pointer')
+            return ptr_val.cast(ptr_type)
+        return self.val['_M_refcount']['_M_pi']
+
+    def to_string (self):
+        state = 'empty'
+        refcounts = self._get_refcounts()
+        targ = self.val.type.template_argument(0)
+        targ = strip_versioned_namespace(str(targ))
+
+        if refcounts != 0:
+            usecount = refcounts['_M_use_count']
+            weakcount = refcounts['_M_weak_count']
+            if usecount == 0:
+                state = 'expired, weak count %d' % weakcount
+            else:
+                state = 'use count %d, weak count %d' % (usecount, weakcount - 1)
+        return '%s<%s> (%s)' % (self.typename, targ, state)
+
+def _tuple_impl_get(val):
+    "Return the tuple element stored in a _Tuple_impl<N, T> base class."
+    bases = val.type.fields()
+    if not bases[-1].is_base_class:
+        raise ValueError("Unsupported implementation for std::tuple: %s" % str(val.type))
+    # Get the _Head_base<N, T> base class:
+    head_base = val.cast(bases[-1].type)
+    fields = head_base.type.fields()
+    if len(fields) == 0:
+        raise ValueError("Unsupported implementation for std::tuple: %s" % str(val.type))
+    if fields[0].name == '_M_head_impl':
+        # The tuple element is the _Head_base::_M_head_impl data member.
+        return head_base['_M_head_impl']
+    elif fields[0].is_base_class:
+        # The tuple element is an empty base class of _Head_base.
+        # Cast to that empty base class.
+        return head_base.cast(fields[0].type)
+    else:
+        raise ValueError("Unsupported implementation for std::tuple: %s" % str(val.type))
+
+def tuple_get(n, val):
+    "Return the result of std::get<n>(val) on a std::tuple"
+    tuple_size = len(get_template_arg_list(val.type))
+    if n > tuple_size:
+        raise ValueError("Out of range index for std::get<N> on std::tuple")
+    # Get the first _Tuple_impl<0, T...> base class:
+    node = val.cast(val.type.fields()[0].type)
+    while n > 0:
+        # Descend through the base classes until the Nth one.
+        node = node.cast(node.type.fields()[0].type)
+        n -= 1
+    return _tuple_impl_get(node)
+
+def unique_ptr_get(val):
+    "Return the result of val.get() on a std::unique_ptr"
+    # std::unique_ptr<T, D> contains a std::tuple<D::pointer, D>,
+    # either as a direct data member _M_t (the old implementation)
+    # or within a data member of type __uniq_ptr_data.
+    impl_type = val.type.fields()[0].type.strip_typedefs()
+    # Check for new implementations first:
+    if is_specialization_of(impl_type, '__uniq_ptr_data') \
+        or is_specialization_of(impl_type, '__uniq_ptr_impl'):
+        tuple_member = val['_M_t']['_M_t']
+    elif is_specialization_of(impl_type, 'tuple'):
+        tuple_member = val['_M_t']
+    else:
+        raise ValueError("Unsupported implementation for unique_ptr: %s" % str(impl_type))
+    return tuple_get(0, tuple_member)
+
+class UniquePointerPrinter:
+    "Print a unique_ptr"
+
+    def __init__ (self, typename, val):
+        self.val = val
+
+    def children (self):
+        return SmartPtrIterator(unique_ptr_get(self.val))
+
+    def to_string (self):
+        return ('std::unique_ptr<%s>' % (str(self.val.type.template_argument(0))))
+
+def get_value_from_aligned_membuf(buf, valtype):
+    """Returns the value held in a __gnu_cxx::__aligned_membuf."""
+    return buf['_M_storage'].address.cast(valtype.pointer()).dereference()
+
+def get_value_from_list_node(node):
+    """Returns the value held in an _List_node<_Val>"""
+    try:
+        member = node.type.fields()[1].name
+        if member == '_M_data':
+            # C++03 implementation, node contains the value as a member
+            return node['_M_data']
+        elif member == '_M_storage':
+            # C++11 implementation, node stores value in __aligned_membuf
+            valtype = node.type.template_argument(0)
+            return get_value_from_aligned_membuf(node['_M_storage'], valtype)
+    except:
+        pass
+    raise ValueError("Unsupported implementation for %s" % str(node.type))
+
+class StdListPrinter:
+    "Print a std::list"
+
+    class _iterator(Iterator):
+        def __init__(self, nodetype, head):
+            self.nodetype = nodetype
+            self.base = head['_M_next']
+            self.head = head.address
+            self.count = 0
+
+        def __iter__(self):
+            return self
+
+        def __next__(self):
+            if self.base == self.head:
+                raise StopIteration
+            elt = self.base.cast(self.nodetype).dereference()
+            self.base = elt['_M_next']
+            count = self.count
+            self.count = self.count + 1
+            val = get_value_from_list_node(elt)
+            return ('[%d]' % count, val)
+
+    def __init__(self, typename, val):
+        self.typename = strip_versioned_namespace(typename)
+        self.val = val
+
+    def children(self):
+        nodetype = lookup_node_type('_List_node', self.val.type).pointer()
+        return self._iterator(nodetype, self.val['_M_impl']['_M_node'])
+
+    def to_string(self):
+        headnode = self.val['_M_impl']['_M_node']
+        if headnode['_M_next'] == headnode.address:
+            return 'empty %s' % (self.typename)
+        return '%s' % (self.typename)
+
+class NodeIteratorPrinter:
+    def __init__(self, typename, val, contname, nodename):
+        self.val = val
+        self.typename = typename
+        self.contname = contname
+        self.nodetype = lookup_node_type(nodename, val.type)
+
+    def to_string(self):
+        if not self.val['_M_node']:
+            return 'non-dereferenceable iterator for std::%s' % (self.contname)
+        node = self.val['_M_node'].cast(self.nodetype.pointer()).dereference()
+        return str(get_value_from_list_node(node))
+
+class StdListIteratorPrinter(NodeIteratorPrinter):
+    "Print std::list::iterator"
+
+    def __init__(self, typename, val):
+        NodeIteratorPrinter.__init__(self, typename, val, 'list', '_List_node')
+
+class StdFwdListIteratorPrinter(NodeIteratorPrinter):
+    "Print std::forward_list::iterator"
+
+    def __init__(self, typename, val):
+        NodeIteratorPrinter.__init__(self, typename, val, 'forward_list',
+                                     '_Fwd_list_node')
+
+class StdSlistPrinter:
+    "Print a __gnu_cxx::slist"
+
+    class _iterator(Iterator):
+        def __init__(self, nodetype, head):
+            self.nodetype = nodetype
+            self.base = head['_M_head']['_M_next']
+            self.count = 0
+
+        def __iter__(self):
+            return self
+
+        def __next__(self):
+            if self.base == 0:
+                raise StopIteration
+            elt = self.base.cast(self.nodetype).dereference()
+            self.base = elt['_M_next']
+            count = self.count
+            self.count = self.count + 1
+            return ('[%d]' % count, elt['_M_data'])
+
+    def __init__(self, typename, val):
+        self.val = val
+
+    def children(self):
+        nodetype = lookup_node_type('__gnu_cxx::_Slist_node', self.val.type)
+        return self._iterator(nodetype.pointer(), self.val)
+
+    def to_string(self):
+        if self.val['_M_head']['_M_next'] == 0:
+            return 'empty __gnu_cxx::slist'
+        return '__gnu_cxx::slist'
+
+class StdSlistIteratorPrinter:
+    "Print __gnu_cxx::slist::iterator"
+
+    def __init__(self, typename, val):
+        self.val = val
+
+    def to_string(self):
+        if not self.val['_M_node']:
+            return 'non-dereferenceable iterator for __gnu_cxx::slist'
+        nodetype = lookup_node_type('__gnu_cxx::_Slist_node', self.val.type).pointer()
+        return str(self.val['_M_node'].cast(nodetype).dereference()['_M_data'])
+
+class StdVectorPrinter:
+    "Print a std::vector"
+
+    class _iterator(Iterator):
+        def __init__ (self, start, finish, bitvec):
+            self.bitvec = bitvec
+            if bitvec:
+                self.item   = start['_M_p']
+                self.so     = 0
+                self.finish = finish['_M_p']
+                self.fo     = finish['_M_offset']
+                itype = self.item.dereference().type
+                self.isize = 8 * itype.sizeof
+            else:
+                self.item = start
+                self.finish = finish
+            self.count = 0
+
+        def __iter__(self):
+            return self
+
+        def __next__(self):
+            count = self.count
+            self.count = self.count + 1
+            if self.bitvec:
+                if self.item == self.finish and self.so >= self.fo:
+                    raise StopIteration
+                elt = bool(self.item.dereference() & (1 << self.so))
+                self.so = self.so + 1
+                if self.so >= self.isize:
+                    self.item = self.item + 1
+                    self.so = 0
+                return ('[%d]' % count, elt)
+            else:
+                if self.item == self.finish:
+                    raise StopIteration
+                elt = self.item.dereference()
+                self.item = self.item + 1
+                return ('[%d]' % count, elt)
+
+    def __init__(self, typename, val):
+        self.typename = strip_versioned_namespace(typename)
+        self.val = val
+        self.is_bool = val.type.template_argument(0).code == gdb.TYPE_CODE_BOOL
+
+    def children(self):
+        return self._iterator(self.val['_M_impl']['_M_start'],
+                              self.val['_M_impl']['_M_finish'],
+                              self.is_bool)
+
+    def to_string(self):
+        start = self.val['_M_impl']['_M_start']
+        finish = self.val['_M_impl']['_M_finish']
+        end = self.val['_M_impl']['_M_end_of_storage']
+        if self.is_bool:
+            start = self.val['_M_impl']['_M_start']['_M_p']
+            finish = self.val['_M_impl']['_M_finish']['_M_p']
+            fo     = self.val['_M_impl']['_M_finish']['_M_offset']
+            itype = start.dereference().type
+            bl = 8 * itype.sizeof
+            length   = bl * (finish - start) + fo
+            capacity = bl * (end - start)
+            return ('%s<bool> of length %d, capacity %d'
+                    % (self.typename, int (length), int (capacity)))
+        else:
+            return ('%s of length %d, capacity %d'
+                    % (self.typename, int (finish - start), int (end - start)))
+
+    def display_hint(self):
+        return 'array'
+
+class StdVectorIteratorPrinter:
+    "Print std::vector::iterator"
+
+    def __init__(self, typename, val):
+        self.val = val
+
+    def to_string(self):
+        if not self.val['_M_current']:
+            return 'non-dereferenceable iterator for std::vector'
+        return str(self.val['_M_current'].dereference())
+
+class StdBitIteratorPrinter:
+    "Print std::vector<bool>'s _Bit_iterator and _Bit_const_iterator"
+
+    def __init__(self, typename, val):
+        self.val = val
+
+    def to_string(self):
+        if not self.val['_M_p']:
+            return 'non-dereferenceable iterator for std::vector<bool>'
+        return bool(self.val['_M_p'].dereference() & (1 << self.val['_M_offset']))
+
+class StdBitReferencePrinter:
+    "Print std::vector<bool>::reference"
+
+    def __init__(self, typename, val):
+        self.val = val
+
+    def to_string(self):
+        if not self.val['_M_p']:
+            return 'invalid std::vector<bool>::reference'
+        return bool(self.val['_M_p'].dereference() & (self.val['_M_mask']))
+
+class StdTuplePrinter:
+    "Print a std::tuple"
+
+    class _iterator(Iterator):
+        @staticmethod
+        def _is_nonempty_tuple (nodes):
+            if len (nodes) == 2:
+                if is_specialization_of (nodes[1].type, '__tuple_base'):
+                    return True
+            elif len (nodes) == 1:
+                return True
+            elif len (nodes) == 0:
+                return False
+            raise ValueError("Top of tuple tree does not consist of a single node.")
+
+        def __init__ (self, head):
+            self.head = head
+
+            # Set the base class as the initial head of the
+            # tuple.
+            nodes = self.head.type.fields ()
+            if self._is_nonempty_tuple (nodes):
+                # Set the actual head to the first pair.
+                self.head  = self.head.cast (nodes[0].type)
+            self.count = 0
+
+        def __iter__ (self):
+            return self
+
+        def __next__ (self):
+            # Check for further recursions in the inheritance tree.
+            # For a GCC 5+ tuple self.head is None after visiting all nodes:
+            if not self.head:
+                raise StopIteration
+            nodes = self.head.type.fields ()
+            # For a GCC 4.x tuple there is a final node with no fields:
+            if len (nodes) == 0:
+                raise StopIteration
+            # Check that this iteration has an expected structure.
+            if len (nodes) > 2:
+                raise ValueError("Cannot parse more than 2 nodes in a tuple tree.")
+
+            if len (nodes) == 1:
+                # This is the last node of a GCC 5+ std::tuple.
+                impl = self.head.cast (nodes[0].type)
+                self.head = None
+            else:
+                # Either a node before the last node, or the last node of
+                # a GCC 4.x tuple (which has an empty parent).
+
+                # - Left node is the next recursion parent.
+                # - Right node is the actual class contained in the tuple.
+
+                # Process right node.
+                impl = self.head.cast (nodes[1].type)
+
+                # Process left node and set it as head.
+                self.head  = self.head.cast (nodes[0].type)
+
+            self.count = self.count + 1
+
+            # Finally, check the implementation.  If it is
+            # wrapped in _M_head_impl return that, otherwise return
+            # the value "as is".
+            fields = impl.type.fields ()
+            if len (fields) < 1 or fields[0].name != "_M_head_impl":
+                return ('[%d]' % self.count, impl)
+            else:
+                return ('[%d]' % self.count, impl['_M_head_impl'])
+
+    def __init__ (self, typename, val):
+        self.typename = strip_versioned_namespace(typename)
+        self.val = val;
+
+    def children (self):
+        return self._iterator (self.val)
+
+    def to_string (self):
+        if len (self.val.type.fields ()) == 0:
+            return 'empty %s' % (self.typename)
+        return '%s containing' % (self.typename)
+
+class StdStackOrQueuePrinter:
+    "Print a std::stack or std::queue"
+
+    def __init__ (self, typename, val):
+        self.typename = strip_versioned_namespace(typename)
+        self.visualizer = gdb.default_visualizer(val['c'])
+
+    def children (self):
+        return self.visualizer.children()
+
+    def to_string (self):
+        return '%s wrapping: %s' % (self.typename,
+                                    self.visualizer.to_string())
+
+    def display_hint (self):
+        if hasattr (self.visualizer, 'display_hint'):
+            return self.visualizer.display_hint ()
+        return None
+
+class RbtreeIterator(Iterator):
+    """
+    Turn an RB-tree-based container (std::map, std::set etc.) into
+    a Python iterable object.
+    """
+
+    def __init__(self, rbtree):
+        self.size = rbtree['_M_t']['_M_impl']['_M_node_count']
+        self.node = rbtree['_M_t']['_M_impl']['_M_header']['_M_left']
+        self.count = 0
+
+    def __iter__(self):
+        return self
+
+    def __len__(self):
+        return int (self.size)
+
+    def __next__(self):
+        if self.count == self.size:
+            raise StopIteration
+        result = self.node
+        self.count = self.count + 1
+        if self.count < self.size:
+            # Compute the next node.
+            node = self.node
+            if node.dereference()['_M_right']:
+                node = node.dereference()['_M_right']
+                while node.dereference()['_M_left']:
+                    node = node.dereference()['_M_left']
+            else:
+                parent = node.dereference()['_M_parent']
+                while node == parent.dereference()['_M_right']:
+                    node = parent
+                    parent = parent.dereference()['_M_parent']
+                if node.dereference()['_M_right'] != parent:
+                    node = parent
+            self.node = node
+        return result
+
+def get_value_from_Rb_tree_node(node):
+    """Returns the value held in an _Rb_tree_node<_Val>"""
+    try:
+        member = node.type.fields()[1].name
+        if member == '_M_value_field':
+            # C++03 implementation, node contains the value as a member
+            return node['_M_value_field']
+        elif member == '_M_storage':
+            # C++11 implementation, node stores value in __aligned_membuf
+            valtype = node.type.template_argument(0)
+            return get_value_from_aligned_membuf(node['_M_storage'], valtype)
+    except:
+        pass
+    raise ValueError("Unsupported implementation for %s" % str(node.type))
+
+# This is a pretty printer for std::_Rb_tree_iterator (which is
+# std::map::iterator), and has nothing to do with the RbtreeIterator
+# class above.
+class StdRbtreeIteratorPrinter:
+    "Print std::map::iterator, std::set::iterator, etc."
+
+    def __init__ (self, typename, val):
+        self.val = val
+        nodetype = lookup_node_type('_Rb_tree_node', self.val.type)
+        self.link_type = nodetype.pointer()
+
+    def to_string (self):
+        if not self.val['_M_node']:
+            return 'non-dereferenceable iterator for associative container'
+        node = self.val['_M_node'].cast(self.link_type).dereference()
+        return str(get_value_from_Rb_tree_node(node))
+
+class StdDebugIteratorPrinter:
+    "Print a debug enabled version of an iterator"
+
+    def __init__ (self, typename, val):
+        self.val = val
+
+    # Just strip away the encapsulating __gnu_debug::_Safe_iterator
+    # and return the wrapped iterator value.
+    def to_string (self):
+        base_type = gdb.lookup_type('__gnu_debug::_Safe_iterator_base')
+        itype = self.val.type.template_argument(0)
+        safe_seq = self.val.cast(base_type)['_M_sequence']
+        if not safe_seq:
+            return str(self.val.cast(itype))
+        if self.val['_M_version'] != safe_seq['_M_version']:
+            return "invalid iterator"
+        return str(self.val.cast(itype))
+
+def num_elements(num):
+    """Return either "1 element" or "N elements" depending on the argument."""
+    return '1 element' if num == 1 else '%d elements' % num
+
+class StdMapPrinter:
+    "Print a std::map or std::multimap"
+
+    # Turn an RbtreeIterator into a pretty-print iterator.
+    class _iter(Iterator):
+        def __init__(self, rbiter, type):
+            self.rbiter = rbiter
+            self.count = 0
+            self.type = type
+
+        def __iter__(self):
+            return self
+
+        def __next__(self):
+            if self.count % 2 == 0:
+                n = next(self.rbiter)
+                n = n.cast(self.type).dereference()
+                n = get_value_from_Rb_tree_node(n)
+                self.pair = n
+                item = n['first']
+            else:
+                item = self.pair['second']
+            result = ('[%d]' % self.count, item)
+            self.count = self.count + 1
+            return result
+
+    def __init__ (self, typename, val):
+        self.typename = strip_versioned_namespace(typename)
+        self.val = val
+
+    def to_string (self):
+        return '%s with %s' % (self.typename,
+                               num_elements(len(RbtreeIterator (self.val))))
+
+    def children (self):
+        node = lookup_node_type('_Rb_tree_node', self.val.type).pointer()
+        return self._iter (RbtreeIterator (self.val), node)
+
+    def display_hint (self):
+        return 'map'
+
+class StdSetPrinter:
+    "Print a std::set or std::multiset"
+
+    # Turn an RbtreeIterator into a pretty-print iterator.
+    class _iter(Iterator):
+        def __init__(self, rbiter, type):
+            self.rbiter = rbiter
+            self.count = 0
+            self.type = type
+
+        def __iter__(self):
+            return self
+
+        def __next__(self):
+            item = next(self.rbiter)
+            item = item.cast(self.type).dereference()
+            item = get_value_from_Rb_tree_node(item)
+            # FIXME: this is weird ... what to do?
+            # Maybe a 'set' display hint?
+            result = ('[%d]' % self.count, item)
+            self.count = self.count + 1
+            return result
+
+    def __init__ (self, typename, val):
+        self.typename = strip_versioned_namespace(typename)
+        self.val = val
+
+    def to_string (self):
+        return '%s with %s' % (self.typename,
+                               num_elements(len(RbtreeIterator (self.val))))
+
+    def children (self):
+        node = lookup_node_type('_Rb_tree_node', self.val.type).pointer()
+        return self._iter (RbtreeIterator (self.val), node)
+
+class StdBitsetPrinter:
+    "Print a std::bitset"
+
+    def __init__(self, typename, val):
+        self.typename = strip_versioned_namespace(typename)
+        self.val = val
+
+    def to_string (self):
+        # If template_argument handled values, we could print the
+        # size.  Or we could use a regexp on the type.
+        return '%s' % (self.typename)
+
+    def children (self):
+        try:
+            # An empty bitset may not have any members which will
+            # result in an exception being thrown.
+            words = self.val['_M_w']
+        except:
+            return []
+
+        wtype = words.type
+
+        # The _M_w member can be either an unsigned long, or an
+        # array.  This depends on the template specialization used.
+        # If it is a single long, convert to a single element list.
+        if wtype.code == gdb.TYPE_CODE_ARRAY:
+            tsize = wtype.target ().sizeof
+        else:
+            words = [words]
+            tsize = wtype.sizeof
+
+        nwords = wtype.sizeof / tsize
+        result = []
+        byte = 0
+        while byte < nwords:
+            w = words[byte]
+            bit = 0
+            while w != 0:
+                if (w & 1) != 0:
+                    # Another spot where we could use 'set'?
+                    result.append(('[%d]' % (byte * tsize * 8 + bit), 1))
+                bit = bit + 1
+                w = w >> 1
+            byte = byte + 1
+        return result
+
+class StdDequePrinter:
+    "Print a std::deque"
+
+    class _iter(Iterator):
+        def __init__(self, node, start, end, last, buffer_size):
+            self.node = node
+            self.p = start
+            self.end = end
+            self.last = last
+            self.buffer_size = buffer_size
+            self.count = 0
+
+        def __iter__(self):
+            return self
+
+        def __next__(self):
+            if self.p == self.last:
+                raise StopIteration
+
+            result = ('[%d]' % self.count, self.p.dereference())
+            self.count = self.count + 1
+
+            # Advance the 'cur' pointer.
+            self.p = self.p + 1
+            if self.p == self.end:
+                # If we got to the end of this bucket, move to the
+                # next bucket.
+                self.node = self.node + 1
+                self.p = self.node[0]
+                self.end = self.p + self.buffer_size
+
+            return result
+
+    def __init__(self, typename, val):
+        self.typename = strip_versioned_namespace(typename)
+        self.val = val
+        self.elttype = val.type.template_argument(0)
+        size = self.elttype.sizeof
+        if size < 512:
+            self.buffer_size = int (512 / size)
+        else:
+            self.buffer_size = 1
+
+    def to_string(self):
+        start = self.val['_M_impl']['_M_start']
+        end = self.val['_M_impl']['_M_finish']
+
+        delta_n = end['_M_node'] - start['_M_node'] - 1
+        delta_s = start['_M_last'] - start['_M_cur']
+        delta_e = end['_M_cur'] - end['_M_first']
+
+        size = self.buffer_size * delta_n + delta_s + delta_e
+
+        return '%s with %s' % (self.typename, num_elements(long(size)))
+
+    def children(self):
+        start = self.val['_M_impl']['_M_start']
+        end = self.val['_M_impl']['_M_finish']
+        return self._iter(start['_M_node'], start['_M_cur'], start['_M_last'],
+                          end['_M_cur'], self.buffer_size)
+
+    def display_hint (self):
+        return 'array'
+
+class StdDequeIteratorPrinter:
+    "Print std::deque::iterator"
+
+    def __init__(self, typename, val):
+        self.val = val
+
+    def to_string(self):
+        if not self.val['_M_cur']:
+            return 'non-dereferenceable iterator for std::deque'
+        return str(self.val['_M_cur'].dereference())
+
+class StdStringPrinter:
+    "Print a std::basic_string of some kind"
+
+    def __init__(self, typename, val):
+        self.val = val
+        self.new_string = typename.find("::__cxx11::basic_string") != -1
+
+    def to_string(self):
+        # Make sure &string works, too.
+        type = self.val.type
+        if type.code == gdb.TYPE_CODE_REF:
+            type = type.target ()
+
+        # Calculate the length of the string so that to_string returns
+        # the string according to length, not according to first null
+        # encountered.
+        ptr = self.val ['_M_dataplus']['_M_p']
+        if self.new_string:
+            length = self.val['_M_string_length']
+            # https://sourceware.org/bugzilla/show_bug.cgi?id=17728
+            ptr = ptr.cast(ptr.type.strip_typedefs())
+        else:
+            realtype = type.unqualified ().strip_typedefs ()
+            reptype = gdb.lookup_type (str (realtype) + '::_Rep').pointer ()
+            header = ptr.cast(reptype) - 1
+            length = header.dereference ()['_M_length']
+        if hasattr(ptr, "lazy_string"):
+            return ptr.lazy_string (length = length)
+        return ptr.string (length = length)
+
+    def display_hint (self):
+        return 'string'
+
+class Tr1HashtableIterator(Iterator):
+    def __init__ (self, hashtable):
+        self.buckets = hashtable['_M_buckets']
+        self.bucket = 0
+        self.bucket_count = hashtable['_M_bucket_count']
+        self.node_type = find_type(hashtable.type, '_Node').pointer()
+        self.node = 0
+        while self.bucket != self.bucket_count:
+            self.node = self.buckets[self.bucket]
+            if self.node:
+                break
+            self.bucket = self.bucket + 1
+
+    def __iter__ (self):
+        return self
+
+    def __next__ (self):
+        if self.node == 0:
+            raise StopIteration
+        node = self.node.cast(self.node_type)
+        result = node.dereference()['_M_v']
+        self.node = node.dereference()['_M_next'];
+        if self.node == 0:
+            self.bucket = self.bucket + 1
+            while self.bucket != self.bucket_count:
+                self.node = self.buckets[self.bucket]
+                if self.node:
+                    break
+                self.bucket = self.bucket + 1
+        return result
+
+class StdHashtableIterator(Iterator):
+    def __init__(self, hashtable):
+        self.node = hashtable['_M_before_begin']['_M_nxt']
+        valtype = hashtable.type.template_argument(1)
+        cached = hashtable.type.template_argument(9).template_argument(0)
+        node_type = lookup_templ_spec('std::__detail::_Hash_node', str(valtype),
+                                      'true' if cached else 'false')
+        self.node_type = node_type.pointer()
+
+    def __iter__(self):
+        return self
+
+    def __next__(self):
+        if self.node == 0:
+            raise StopIteration
+        elt = self.node.cast(self.node_type).dereference()
+        self.node = elt['_M_nxt']
+        valptr = elt['_M_storage'].address
+        valptr = valptr.cast(elt.type.template_argument(0).pointer())
+        return valptr.dereference()
+
+class Tr1UnorderedSetPrinter:
+    "Print a std::unordered_set or tr1::unordered_set"
+
+    def __init__ (self, typename, val):
+        self.typename = strip_versioned_namespace(typename)
+        self.val = val
+
+    def hashtable (self):
+        if self.typename.startswith('std::tr1'):
+            return self.val
+        return self.val['_M_h']
+
+    def to_string (self):
+        count = self.hashtable()['_M_element_count']
+        return '%s with %s' % (self.typename, num_elements(count))
+
+    @staticmethod
+    def format_count (i):
+        return '[%d]' % i
+
+    def children (self):
+        counter = imap (self.format_count, itertools.count())
+        if self.typename.startswith('std::tr1'):
+            return izip (counter, Tr1HashtableIterator (self.hashtable()))
+        return izip (counter, StdHashtableIterator (self.hashtable()))
+
+class Tr1UnorderedMapPrinter:
+    "Print a std::unordered_map or tr1::unordered_map"
+
+    def __init__ (self, typename, val):
+        self.typename = strip_versioned_namespace(typename)
+        self.val = val
+
+    def hashtable (self):
+        if self.typename.startswith('std::tr1'):
+            return self.val
+        return self.val['_M_h']
+
+    def to_string (self):
+        count = self.hashtable()['_M_element_count']
+        return '%s with %s' % (self.typename, num_elements(count))
+
+    @staticmethod
+    def flatten (list):
+        for elt in list:
+            for i in elt:
+                yield i
+
+    @staticmethod
+    def format_one (elt):
+        return (elt['first'], elt['second'])
+
+    @staticmethod
+    def format_count (i):
+        return '[%d]' % i
+
+    def children (self):
+        counter = imap (self.format_count, itertools.count())
+        # Map over the hash table and flatten the result.
+        if self.typename.startswith('std::tr1'):
+            data = self.flatten (imap (self.format_one, Tr1HashtableIterator (self.hashtable())))
+            # Zip the two iterators together.
+            return izip (counter, data)
+        data = self.flatten (imap (self.format_one, StdHashtableIterator (self.hashtable())))
+        # Zip the two iterators together.
+        return izip (counter, data)
+
+    def display_hint (self):
+        return 'map'
+
+class StdForwardListPrinter:
+    "Print a std::forward_list"
+
+    class _iterator(Iterator):
+        def __init__(self, nodetype, head):
+            self.nodetype = nodetype
+            self.base = head['_M_next']
+            self.count = 0
+
+        def __iter__(self):
+            return self
+
+        def __next__(self):
+            if self.base == 0:
+                raise StopIteration
+            elt = self.base.cast(self.nodetype).dereference()
+            self.base = elt['_M_next']
+            count = self.count
+            self.count = self.count + 1
+            valptr = elt['_M_storage'].address
+            valptr = valptr.cast(elt.type.template_argument(0).pointer())
+            return ('[%d]' % count, valptr.dereference())
+
+    def __init__(self, typename, val):
+        self.val = val
+        self.typename = strip_versioned_namespace(typename)
+
+    def children(self):
+        nodetype = lookup_node_type('_Fwd_list_node', self.val.type).pointer()
+        return self._iterator(nodetype, self.val['_M_impl']['_M_head'])
+
+    def to_string(self):
+        if self.val['_M_impl']['_M_head']['_M_next'] == 0:
+            return 'empty %s' % self.typename
+        return '%s' % self.typename
+
+class SingleObjContainerPrinter(object):
+    "Base class for printers of containers of single objects"
+
+    def __init__ (self, val, viz, hint = None):
+        self.contained_value = val
+        self.visualizer = viz
+        self.hint = hint
+
+    def _recognize(self, type):
+        """Return TYPE as a string after applying type printers"""
+        global _use_type_printing
+        if not _use_type_printing:
+            return str(type)
+        return gdb.types.apply_type_recognizers(gdb.types.get_type_recognizers(),
+                                                type) or str(type)
+
+    class _contained(Iterator):
+        def __init__ (self, val):
+            self.val = val
+
+        def __iter__ (self):
+            return self
+
+        def __next__(self):
+            if self.val is None:
+                raise StopIteration
+            retval = self.val
+            self.val = None
+            return ('[contained value]', retval)
+
+    def children (self):
+        if self.contained_value is None:
+            return self._contained (None)
+        if hasattr (self.visualizer, 'children'):
+            return self.visualizer.children ()
+        return self._contained (self.contained_value)
+
+    def display_hint (self):
+        # if contained value is a map we want to display in the same way
+        if hasattr (self.visualizer, 'children') and hasattr (self.visualizer, 'display_hint'):
+            return self.visualizer.display_hint ()
+        return self.hint
+
+def function_pointer_to_name(f):
+    "Find the name of the function referred to by the gdb.Value f, "
+    " which should contain a function pointer from the program."
+
+    # Turn the function pointer into an actual address.
+    # This is needed to unpack ppc64 function descriptors.
+    f = f.dereference().address
+
+    if sys.version_info[0] == 2:
+        # Older versions of GDB need to use long for Python 2,
+        # because int(f) on 64-bit big-endian values raises a
+        # gdb.error saying "Cannot convert value to int."
+        f = long(f)
+    else:
+        f = int(f)
+
+    try:
+        # If the function can't be found older versions of GDB raise a
+        # RuntimeError saying "Cannot locate object file for block."
+        return gdb.block_for_pc(f).function.name
+    except:
+        return None
+
+class StdExpAnyPrinter(SingleObjContainerPrinter):
+    "Print a std::any or std::experimental::any"
+
+    def __init__ (self, typename, val):
+        self.typename = strip_versioned_namespace(typename)
+        self.typename = re.sub('^std::experimental::fundamentals_v\d::', 'std::experimental::', self.typename, 1)
+        self.val = val
+        self.contained_type = None
+        contained_value = None
+        visualizer = None
+        mgr = self.val['_M_manager']
+        if mgr != 0:
+            func = function_pointer_to_name(mgr)
+            if not func:
+                raise ValueError("Invalid function pointer in %s" % (self.typename))
+            rx = r"""({0}::_Manager_\w+<.*>)::_S_manage\((enum )?{0}::_Op, (const {0}|{0} const) ?\*, (union )?{0}::_Arg ?\*\)""".format(typename)
+            m = re.match(rx, func)
+            if not m:
+                raise ValueError("Unknown manager function in %s" % self.typename)
+
+            mgrname = m.group(1)
+            # FIXME need to expand 'std::string' so that gdb.lookup_type works
+            if 'std::string' in mgrname:
+                mgrname = re.sub("std::string(?!\w)", str(gdb.lookup_type('std::string').strip_typedefs()), m.group(1))
+
+            mgrtype = gdb.lookup_type(mgrname)
+            self.contained_type = mgrtype.template_argument(0)
+            valptr = None
+            if '::_Manager_internal' in mgrname:
+                valptr = self.val['_M_storage']['_M_buffer'].address
+            elif '::_Manager_external' in mgrname:
+                valptr = self.val['_M_storage']['_M_ptr']
+            else:
+                raise ValueError("Unknown manager function in %s" % self.typename)
+            contained_value = valptr.cast(self.contained_type.pointer()).dereference()
+            visualizer = gdb.default_visualizer(contained_value)
+        super(StdExpAnyPrinter, self).__init__ (contained_value, visualizer)
+
+    def to_string (self):
+        if self.contained_type is None:
+            return '%s [no contained value]' % self.typename
+        desc = "%s containing " % self.typename
+        if hasattr (self.visualizer, 'children'):
+            return desc + self.visualizer.to_string ()
+        valtype = self._recognize (self.contained_type)
+        return desc + strip_versioned_namespace(str(valtype))
+
+class StdExpOptionalPrinter(SingleObjContainerPrinter):
+    "Print a std::optional or std::experimental::optional"
+
+    def __init__ (self, typename, val):
+        valtype = self._recognize (val.type.template_argument(0))
+        typename = strip_versioned_namespace(typename)
+        self.typename = re.sub('^std::(experimental::|)(fundamentals_v\d::|)(.*)', r'std::\1\3<%s>' % valtype, typename, 1)
+        payload = val['_M_payload']
+        if self.typename.startswith('std::experimental'):
+            engaged = val['_M_engaged']
+            contained_value = payload
+        else:
+            engaged = payload['_M_engaged']
+            contained_value = payload['_M_payload']
+            try:
+                # Since GCC 9
+                contained_value = contained_value['_M_value']
+            except:
+                pass
+        visualizer = gdb.default_visualizer (contained_value)
+        if not engaged:
+            contained_value = None
+        super (StdExpOptionalPrinter, self).__init__ (contained_value, visualizer)
+
+    def to_string (self):
+        if self.contained_value is None:
+            return "%s [no contained value]" % self.typename
+        if hasattr (self.visualizer, 'children'):
+            return "%s containing %s" % (self.typename,
+                                         self.visualizer.to_string())
+        return self.typename
+
+class StdVariantPrinter(SingleObjContainerPrinter):
+    "Print a std::variant"
+
+    def __init__(self, typename, val):
+        alternatives = get_template_arg_list(val.type)
+        self.typename = strip_versioned_namespace(typename)
+        self.typename = "%s<%s>" % (self.typename, ', '.join([self._recognize(alt) for alt in alternatives]))
+        self.index = val['_M_index']
+        if self.index >= len(alternatives):
+            self.contained_type = None
+            contained_value = None
+            visualizer = None
+        else:
+            self.contained_type = alternatives[int(self.index)]
+            addr = val['_M_u']['_M_first']['_M_storage'].address
+            contained_value = addr.cast(self.contained_type.pointer()).dereference()
+            visualizer = gdb.default_visualizer(contained_value)
+        super (StdVariantPrinter, self).__init__(contained_value, visualizer, 'array')
+
+    def to_string(self):
+        if self.contained_value is None:
+            return "%s [no contained value]" % self.typename
+        if hasattr(self.visualizer, 'children'):
+            return "%s [index %d] containing %s" % (self.typename, self.index,
+                                                    self.visualizer.to_string())
+        return "%s [index %d]" % (self.typename, self.index)
+
+class StdNodeHandlePrinter(SingleObjContainerPrinter):
+    "Print a container node handle"
+
+    def __init__(self, typename, val):
+        self.value_type = val.type.template_argument(1)
+        nodetype = val.type.template_argument(2).template_argument(0)
+        self.is_rb_tree_node = is_specialization_of(nodetype.name, '_Rb_tree_node')
+        self.is_map_node = val.type.template_argument(0) != self.value_type
+        nodeptr = val['_M_ptr']
+        if nodeptr:
+            if self.is_rb_tree_node:
+                contained_value = get_value_from_Rb_tree_node(nodeptr.dereference())
+            else:
+                contained_value = get_value_from_aligned_membuf(nodeptr['_M_storage'],
+                                                                self.value_type)
+            visualizer = gdb.default_visualizer(contained_value)
+        else:
+            contained_value = None
+            visualizer = None
+        optalloc = val['_M_alloc']
+        self.alloc = optalloc['_M_payload'] if optalloc['_M_engaged'] else None
+        super(StdNodeHandlePrinter, self).__init__(contained_value, visualizer,
+                                                   'array')
+
+    def to_string(self):
+        desc = 'node handle for '
+        if not self.is_rb_tree_node:
+            desc += 'unordered '
+        if self.is_map_node:
+            desc += 'map';
+        else:
+            desc += 'set';
+
+        if self.contained_value:
+            desc += ' with element'
+            if hasattr(self.visualizer, 'children'):
+                return "%s = %s" % (desc, self.visualizer.to_string())
+            return desc
+        else:
+            return 'empty %s' % desc
+
+class StdExpStringViewPrinter:
+    "Print a std::basic_string_view or std::experimental::basic_string_view"
+
+    def __init__ (self, typename, val):
+        self.val = val
+
+    def to_string (self):
+        ptr = self.val['_M_str']
+        len = self.val['_M_len']
+        if hasattr (ptr, "lazy_string"):
+            return ptr.lazy_string (length = len)
+        return ptr.string (length = len)
+
+    def display_hint (self):
+        return 'string'
+
+class StdExpPathPrinter:
+    "Print a std::experimental::filesystem::path"
+
+    def __init__ (self, typename, val):
+        self.val = val
+        self.typename = typename
+        start = self.val['_M_cmpts']['_M_impl']['_M_start']
+        finish = self.val['_M_cmpts']['_M_impl']['_M_finish']
+        self.num_cmpts = int (finish - start)
+
+    def _path_type(self):
+        t = str(self.val['_M_type'])
+        if t[-9:] == '_Root_dir':
+            return "root-directory"
+        if t[-10:] == '_Root_name':
+            return "root-name"
+        return None
+
+    def to_string (self):
+        path = "%s" % self.val ['_M_pathname']
+        if self.num_cmpts == 0:
+            t = self._path_type()
+            if t:
+                path = '%s [%s]' % (path, t)
+        return "experimental::filesystem::path %s" % path
+
+    class _iterator(Iterator):
+        def __init__(self, cmpts, pathtype):
+            self.pathtype = pathtype
+            self.item = cmpts['_M_impl']['_M_start']
+            self.finish = cmpts['_M_impl']['_M_finish']
+            self.count = 0
+
+        def __iter__(self):
+            return self
+
+        def __next__(self):
+            if self.item == self.finish:
+                raise StopIteration
+            item = self.item.dereference()
+            count = self.count
+            self.count = self.count + 1
+            self.item = self.item + 1
+            path = item['_M_pathname']
+            t = StdExpPathPrinter(self.pathtype, item)._path_type()
+            if not t:
+                t = count
+            return ('[%s]' % t, path)
+
+    def children(self):
+        return self._iterator(self.val['_M_cmpts'], self.typename)
+
+class StdPathPrinter:
+    "Print a std::filesystem::path"
+
+    def __init__ (self, typename, val):
+        self.val = val
+        self.typename = typename
+        impl = unique_ptr_get(self.val['_M_cmpts']['_M_impl'])
+        self.type = impl.cast(gdb.lookup_type('uintptr_t')) & 3
+        if self.type == 0:
+            self.impl = impl
+        else:
+            self.impl = None
+
+    def _path_type(self):
+        t = str(self.type.cast(gdb.lookup_type(self.typename + '::_Type')))
+        if t[-9:] == '_Root_dir':
+            return "root-directory"
+        if t[-10:] == '_Root_name':
+            return "root-name"
+        return None
+
+    def to_string (self):
+        path = "%s" % self.val ['_M_pathname']
+        if self.type != 0:
+            t = self._path_type()
+            if t:
+                path = '%s [%s]' % (path, t)
+        return "filesystem::path %s" % path
+
+    class _iterator(Iterator):
+        def __init__(self, impl, pathtype):
+            self.pathtype = pathtype
+            if impl:
+                # We can't access _Impl::_M_size because _Impl is incomplete
+                # so cast to int* to access the _M_size member at offset zero,
+                int_type = gdb.lookup_type('int')
+                cmpt_type = gdb.lookup_type(pathtype+'::_Cmpt')
+                char_type = gdb.lookup_type('char')
+                impl = impl.cast(int_type.pointer())
+                size = impl.dereference()
+                #self.capacity = (impl + 1).dereference()
+                if hasattr(gdb.Type, 'alignof'):
+                    sizeof_Impl = max(2 * int_type.sizeof, cmpt_type.alignof)
+                else:
+                    sizeof_Impl = 2 * int_type.sizeof
+                begin = impl.cast(char_type.pointer()) + sizeof_Impl
+                self.item = begin.cast(cmpt_type.pointer())
+                self.finish = self.item + size
+                self.count = 0
+            else:
+                self.item = None
+                self.finish = None
+
+        def __iter__(self):
+            return self
+
+        def __next__(self):
+            if self.item == self.finish:
+                raise StopIteration
+            item = self.item.dereference()
+            count = self.count
+            self.count = self.count + 1
+            self.item = self.item + 1
+            path = item['_M_pathname']
+            t = StdPathPrinter(self.pathtype, item)._path_type()
+            if not t:
+                t = count
+            return ('[%s]' % t, path)
+
+    def children(self):
+        return self._iterator(self.impl, self.typename)
+
+
+class StdPairPrinter:
+    "Print a std::pair object, with 'first' and 'second' as children"
+
+    def __init__(self, typename, val):
+        self.val = val
+
+    class _iter(Iterator):
+        "An iterator for std::pair types. Returns 'first' then 'second'."
+
+        def __init__(self, val):
+            self.val = val
+            self.which = 'first'
+
+        def __iter__(self):
+            return self
+
+        def __next__(self):
+            if self.which is None:
+                raise StopIteration
+            which = self.which
+            if which == 'first':
+                self.which = 'second'
+            else:
+                self.which = None
+            return (which, self.val[which])
+
+    def children(self):
+        return self._iter(self.val)
+
+    def to_string(self):
+        return None
+
+class StdCmpCatPrinter:
+    "Print a comparison category object"
+
+    def __init__ (self, typename, val):
+        self.typename = typename[typename.rfind(':')+1:]
+        self.val = val['_M_value']
+
+    def to_string (self):
+        if self.typename == 'strong_ordering' and self.val == 0:
+            name = 'equal'
+        else:
+            names = {2:'unordered', -1:'less', 0:'equivalent', 1:'greater'}
+            name = names[int(self.val)]
+        return 'std::{}::{}'.format(self.typename, name)
+
+class StdErrorCodePrinter:
+    "Print a std::error_code or std::error_condition"
+
+    _system_is_posix = None  # Whether std::system_category() use errno values.
+
+    def __init__ (self, typename, val):
+        self.val = val
+        self.typename = strip_versioned_namespace(typename)
+        # Do this only once ...
+        if StdErrorCodePrinter._system_is_posix is None:
+            try:
+                import posix
+                StdErrorCodePrinter._system_is_posix = True
+            except ImportError:
+                StdErrorCodePrinter._system_is_posix = False
+
+    @staticmethod
+    def _find_errc_enum(name):
+        typ = gdb.lookup_type(name)
+        if typ is not None and typ.code == gdb.TYPE_CODE_ENUM:
+            return typ
+        return None
+
+    @classmethod
+    def _find_standard_errc_enum(cls, name):
+        for ns in ['', _versioned_namespace]:
+            try:
+                qname = 'std::{}{}'.format(ns, name)
+                return cls._find_errc_enum(qname)
+            except RuntimeError:
+                pass
+
+    @classmethod
+    def _match_net_ts_category(cls, cat):
+        net_cats = ['stream', 'socket', 'ip::resolver']
+        for c in net_cats:
+            func = c + '_category()'
+            for ns in ['', _versioned_namespace]:
+                ns = 'std::{}experimental::net::v1'.format(ns)
+                sym = gdb.lookup_symbol('{}::{}::__c'.format(ns, func))[0]
+                if sym is not None:
+                    if cat == sym.value().address:
+                        name = 'net::' + func
+                        enum = cls._find_errc_enum('{}::{}_errc'.format(ns, c))
+                        return (name, enum)
+        return (None, None)
+
+    @classmethod
+    def _category_info(cls, cat):
+        "Return details of a std::error_category"
+
+        name = None
+        enum = None
+        is_errno = False
+
+        # Try these first, or we get "warning: RTTI symbol not found" when
+        # using cat.dynamic_type on the local class types for Net TS categories.
+        func, enum = cls._match_net_ts_category(cat)
+        if func is not None:
+            return (None, func, enum, is_errno)
+
+        # This might give a warning for a program-defined category defined as
+        # a local class, but there doesn't seem to be any way to avoid that.
+        typ = cat.dynamic_type.target()
+        # Shortcuts for the known categories defined by libstdc++.
+        if typ.tag.endswith('::generic_error_category'):
+            name = 'generic'
+            is_errno = True
+        if typ.tag.endswith('::system_error_category'):
+            name = 'system'
+            is_errno = cls._system_is_posix
+        if typ.tag.endswith('::future_error_category'):
+            name = 'future'
+            enum = cls._find_standard_errc_enum('future_errc')
+        if typ.tag.endswith('::io_error_category'):
+            name = 'io'
+            enum = cls._find_standard_errc_enum('io_errc')
+
+        if name is None:
+            try:
+                # Want to call std::error_category::name() override, but it's
+                # unsafe: https://sourceware.org/bugzilla/show_bug.cgi?id=28856
+                # gdb.set_convenience_variable('__cat', cat)
+                # return '"%s"' % gdb.parse_and_eval('$__cat->name()').string()
+                pass
+            except:
+                pass
+        return (name, typ.tag, enum, is_errno)
+
+    @staticmethod
+    def _unqualified_name(name):
+        "Strip any nested-name-specifier from NAME to give an unqualified name"
+        return name.split('::')[-1]
+
+    def to_string (self):
+        value = self.val['_M_value']
+        cat = self.val['_M_cat']
+        name, alt_name, enum, is_errno = self._category_info(cat)
+        if value == 0:
+            default_cats = { 'error_code' : 'system',
+                             'error_condition' : 'generic' }
+            if name == default_cats[self._unqualified_name(self.typename)]:
+                return self.typename + ' = { }' # default-constructed value
+
+        strval = str(value)
+        if is_errno and value != 0:
+            try:
+                strval = errno.errorcode[int(value)]
+            except:
+                pass
+        elif enum is not None:
+            strval = self._unqualified_name(str(value.cast(enum)))
+
+        if name is not None:
+            name = '"%s"' % name
+        else:
+            name = alt_name
+        return '%s = {%s: %s}' % (self.typename, name, strval)
+
+
+class StdRegexStatePrinter:
+    "Print a state node in the NFA for a std::regex"
+
+    def __init__ (self, typename, val):
+        self.val = val
+        self.typename = typename
+
+    def to_string (self):
+        opcode = str(self.val['_M_opcode'])
+        if opcode:
+            opcode = opcode[25:]
+        next_id = self.val['_M_next']
+
+        variants = {'repeat':'alt', 'alternative':'alt',
+                    'subexpr_begin':'subexpr', 'subexpr_end':'subexpr',
+                    'line_begin_assertion':None, 'line_end_assertion':None,
+                    'word_boundary':'neg', 'subexpr_lookahead':'neg',
+                    'backref':'backref_index',
+                    'match':None, 'accept':None,
+                    'dummy':None, 'unknown':None
+                   }
+        v = variants[opcode]
+
+        s = "opcode={}, next={}".format(opcode, next_id)
+        if v is not None and self.val['_M_' + v] is not None:
+            s = "{}, {}={}".format(s, v, self.val['_M_' + v])
+        return "{%s}" % (s)
+
+class StdSpanPrinter:
+    "Print a std::span"
+
+    class iterator(Iterator):
+        def __init__(self, begin, size):
+            self.count = 0
+            self.begin = begin
+            self.size = size
+
+        def __iter__ (self):
+            return self
+
+        def __next__ (self):
+            if self.count == self.size:
+                raise StopIteration
+
+            count = self.count
+            self.count = self.count + 1
+            return '[%d]' % count, (self.begin + count).dereference()
+
+    def __init__(self, typename, val):
+        self.typename = strip_versioned_namespace(typename)
+        self.val = val
+        if val.type.template_argument(1) == gdb.parse_and_eval('static_cast<std::size_t>(-1)'):
+            self.size = val['_M_extent']['_M_extent_value']
+        else:
+            self.size = val.type.template_argument(1)
+
+    def to_string(self):
+        return '%s of length %d' % (self.typename, self.size)
+
+    def children(self):
+        return self.iterator(self.val['_M_ptr'], self.size)
+
+    def display_hint(self):
+        return 'array'
+
+class StdInitializerListPrinter:
+    "Print a std::initializer_list"
+
+    def __init__(self, typename, val):
+        self.typename = typename
+        self.val = val
+        self.size = val['_M_len']
+
+    def to_string(self):
+        return '%s of length %d' % (self.typename, self.size)
+
+    def children(self):
+        return StdSpanPrinter.iterator(self.val['_M_array'], self.size)
+
+    def display_hint(self):
+        return 'array'
+
+class StdAtomicPrinter:
+    "Print a std:atomic"
+
+    def __init__(self, typename, val):
+        self.typename = strip_versioned_namespace(typename)
+        self.val = val
+        self.shptr_printer = None
+        self.value_type = self.val.type.template_argument(0)
+        if self.value_type.tag is not None:
+            typ = strip_versioned_namespace(self.value_type.tag)
+            if typ.startswith('std::shared_ptr<') or typ.startswith('std::weak_ptr<'):
+                impl = val['_M_impl']
+                self.shptr_printer = SharedPointerPrinter(typename, impl)
+                self.children = self._shptr_children
+
+    def _shptr_children(self):
+        return SmartPtrIterator(self.shptr_printer.pointer)
+
+    def to_string(self):
+        if self.shptr_printer is not None:
+            return self.shptr_printer.to_string()
+
+        if self.value_type.code == gdb.TYPE_CODE_INT:
+            val = self.val['_M_i']
+        elif self.value_type.code == gdb.TYPE_CODE_FLT:
+            val = self.val['_M_fp']
+        elif self.value_type.code == gdb.TYPE_CODE_PTR:
+            val = self.val['_M_b']['_M_p']
+        elif self.value_type.code == gdb.TYPE_CODE_BOOL:
+            val = self.val['_M_base']['_M_i']
+        else:
+            val = self.val['_M_i']
+        return '%s<%s> = { %s }' % (self.typename, str(self.value_type), val)
+
+# A "regular expression" printer which conforms to the
+# "SubPrettyPrinter" protocol from gdb.printing.
+class RxPrinter(object):
+    def __init__(self, name, function):
+        super(RxPrinter, self).__init__()
+        self.name = name
+        self.function = function
+        self.enabled = True
+
+    def invoke(self, value):
+        if not self.enabled:
+            return None
+
+        if value.type.code == gdb.TYPE_CODE_REF:
+            if hasattr(gdb.Value,"referenced_value"):
+                value = value.referenced_value()
+
+        return self.function(self.name, value)
+
+# A pretty-printer that conforms to the "PrettyPrinter" protocol from
+# gdb.printing.  It can also be used directly as an old-style printer.
+class Printer(object):
+    def __init__(self, name):
+        super(Printer, self).__init__()
+        self.name = name
+        self.subprinters = []
+        self.lookup = {}
+        self.enabled = True
+        self.compiled_rx = re.compile('^([a-zA-Z0-9_:]+)(<.*>)?$')
+
+    def add(self, name, function):
+        # A small sanity check.
+        # FIXME
+        if not self.compiled_rx.match(name):
+            raise ValueError('libstdc++ programming error: "%s" does not match' % name)
+        printer = RxPrinter(name, function)
+        self.subprinters.append(printer)
+        self.lookup[name] = printer
+
+    # Add a name using _GLIBCXX_BEGIN_NAMESPACE_VERSION.
+    def add_version(self, base, name, function):
+        self.add(base + name, function)
+        if _versioned_namespace and not '__cxx11' in base:
+            vbase = re.sub('^(std|__gnu_cxx)::', r'\g<0>%s' % _versioned_namespace, base)
+            self.add(vbase + name, function)
+
+    # Add a name using _GLIBCXX_BEGIN_NAMESPACE_CONTAINER.
+    def add_container(self, base, name, function):
+        self.add_version(base, name, function)
+        self.add_version(base + '__cxx1998::', name, function)
+
+    @staticmethod
+    def get_basic_type(type):
+        # If it points to a reference, get the reference.
+        if type.code == gdb.TYPE_CODE_REF:
+            type = type.target ()
+
+        # Get the unqualified type, stripped of typedefs.
+        type = type.unqualified ().strip_typedefs ()
+
+        return type.tag
+
+    def __call__(self, val):
+        typename = self.get_basic_type(val.type)
+        if not typename:
+            return None
+
+        # All the types we match are template types, so we can use a
+        # dictionary.
+        match = self.compiled_rx.match(typename)
+        if not match:
+            return None
+
+        basename = match.group(1)
+
+        if val.type.code == gdb.TYPE_CODE_REF:
+            if hasattr(gdb.Value,"referenced_value"):
+                val = val.referenced_value()
+
+        if basename in self.lookup:
+            return self.lookup[basename].invoke(val)
+
+        # Cannot find a pretty printer.  Return None.
+        return None
+
+libstdcxx_printer = None
+
+class TemplateTypePrinter(object):
+    r"""
+    A type printer for class templates with default template arguments.
+
+    Recognizes specializations of class templates and prints them without
+    any template arguments that use a default template argument.
+    Type printers are recursively applied to the template arguments.
+
+    e.g. replace "std::vector<T, std::allocator<T> >" with "std::vector<T>".
+    """
+
+    def __init__(self, name, defargs):
+        self.name = name
+        self.defargs = defargs
+        self.enabled = True
+
+    class _recognizer(object):
+        "The recognizer class for TemplateTypePrinter."
+
+        def __init__(self, name, defargs):
+            self.name = name
+            self.defargs = defargs
+            # self.type_obj = None
+
+        def recognize(self, type_obj):
+            """
+            If type_obj is a specialization of self.name that uses all the
+            default template arguments for the class template, then return
+            a string representation of the type without default arguments.
+            Otherwise, return None.
+            """
+
+            if type_obj.tag is None:
+                return None
+
+            if not type_obj.tag.startswith(self.name):
+                return None
+
+            template_args = get_template_arg_list(type_obj)
+            displayed_args = []
+            require_defaulted = False
+            for n in range(len(template_args)):
+                # The actual template argument in the type:
+                targ = template_args[n]
+                # The default template argument for the class template:
+                defarg = self.defargs.get(n)
+                if defarg is not None:
+                    # Substitute other template arguments into the default:
+                    defarg = defarg.format(*template_args)
+                    # Fail to recognize the type (by returning None)
+                    # unless the actual argument is the same as the default.
+                    try:
+                        if targ != gdb.lookup_type(defarg):
+                            return None
+                    except gdb.error:
+                        # Type lookup failed, just use string comparison:
+                        if targ.tag != defarg:
+                            return None
+                    # All subsequent args must have defaults:
+                    require_defaulted = True
+                elif require_defaulted:
+                    return None
+                else:
+                    # Recursively apply recognizers to the template argument
+                    # and add it to the arguments that will be displayed:
+                    displayed_args.append(self._recognize_subtype(targ))
+
+            # This assumes no class templates in the nested-name-specifier:
+            template_name = type_obj.tag[0:type_obj.tag.find('<')]
+            template_name = strip_inline_namespaces(template_name)
+
+            return template_name + '<' + ', '.join(displayed_args) + '>'
+
+        def _recognize_subtype(self, type_obj):
+            """Convert a gdb.Type to a string by applying recognizers,
+            or if that fails then simply converting to a string."""
+
+            if type_obj.code == gdb.TYPE_CODE_PTR:
+                return self._recognize_subtype(type_obj.target()) + '*'
+            if type_obj.code == gdb.TYPE_CODE_ARRAY:
+                type_str = self._recognize_subtype(type_obj.target())
+                if str(type_obj.strip_typedefs()).endswith('[]'):
+                    return type_str + '[]' # array of unknown bound
+                return "%s[%d]" % (type_str, type_obj.range()[1] + 1)
+            if type_obj.code == gdb.TYPE_CODE_REF:
+                return self._recognize_subtype(type_obj.target()) + '&'
+            if hasattr(gdb, 'TYPE_CODE_RVALUE_REF'):
+                if type_obj.code == gdb.TYPE_CODE_RVALUE_REF:
+                    return self._recognize_subtype(type_obj.target()) + '&&'
+
+            type_str = gdb.types.apply_type_recognizers(
+                    gdb.types.get_type_recognizers(), type_obj)
+            if type_str:
+                return type_str
+            return str(type_obj)
+
+    def instantiate(self):
+        "Return a recognizer object for this type printer."
+        return self._recognizer(self.name, self.defargs)
+
+def add_one_template_type_printer(obj, name, defargs):
+    r"""
+    Add a type printer for a class template with default template arguments.
+
+    Args:
+        name (str): The template-name of the class template.
+        defargs (dict int:string) The default template arguments.
+
+    Types in defargs can refer to the Nth template-argument using {N}
+    (with zero-based indices).
+
+    e.g. 'unordered_map' has these defargs:
+    { 2: 'std::hash<{0}>',
+      3: 'std::equal_to<{0}>',
+      4: 'std::allocator<std::pair<const {0}, {1}> >' }
+
+    """
+    printer = TemplateTypePrinter('std::'+name, defargs)
+    gdb.types.register_type_printer(obj, printer)
+
+    # Add type printer for same type in debug namespace:
+    printer = TemplateTypePrinter('std::__debug::'+name, defargs)
+    gdb.types.register_type_printer(obj, printer)
+
+    if _versioned_namespace and not '__cxx11' in name:
+        # Add second type printer for same type in versioned namespace:
+        ns = 'std::' + _versioned_namespace
+        # PR 86112 Cannot use dict comprehension here:
+        defargs = dict((n, d.replace('std::', ns)) for (n,d) in defargs.items())
+        printer = TemplateTypePrinter(ns+name, defargs)
+        gdb.types.register_type_printer(obj, printer)
+
+class FilteringTypePrinter(object):
+    r"""
+    A type printer that uses typedef names for common template specializations.
+
+    Args:
+        template (str): The class template to recognize.
+        name (str): The typedef-name that will be used instead.
+        targ1 (str): The first template argument.
+            If arg1 is provided (not None), match only template specializations
+            with this type as the first template argument,
+            e.g. if template='basic_string<targ1'
+
+    Checks if a specialization of the class template 'template' is the same type
+    as the typedef 'name', and prints it as 'name' instead.
+
+    e.g. if an instantiation of std::basic_istream<C, T> is the same type as
+    std::istream then print it as std::istream.
+    """
+
+    def __init__(self, template, name, targ1):
+        self.template = template
+        self.name = name
+        self.targ1 = targ1
+        self.enabled = True
+
+    class _recognizer(object):
+        "The recognizer class for FilteringTypePrinter."
+
+        def __init__(self, template, name, targ1):
+            self.template = template
+            self.name = name
+            self.targ1 = targ1
+            self.type_obj = None
+
+        def recognize(self, type_obj):
+            """
+            If type_obj starts with self.template and is the same type as
+            self.name then return self.name, otherwise None.
+            """
+            if type_obj.tag is None:
+                return None
+
+            if self.type_obj is None:
+                if self.targ1 is not None:
+                    if not type_obj.tag.startswith('{}<{}'.format(self.template, self.targ1)):
+                        # Filter didn't match.
+                        return None
+                elif not type_obj.tag.startswith(self.template):
+                    # Filter didn't match.
+                    return None
+
+                try:
+                    self.type_obj = gdb.lookup_type(self.name).strip_typedefs()
+                except:
+                    pass
+
+            if self.type_obj is None:
+                return None
+
+            if gdb.types.get_basic_type(self.type_obj) == gdb.types.get_basic_type(type_obj):
+                return strip_inline_namespaces(self.name)
+
+            # Workaround ambiguous typedefs matching both std:: and std::__cxx11:: symbols.
+            if self.template.split('::')[-1] == 'basic_string':
+                if self.type_obj.tag.replace('__cxx11::', '') == type_obj.tag.replace('__cxx11::', ''):
+                    return strip_inline_namespaces(self.name)
+
+            return None
+
+    def instantiate(self):
+        "Return a recognizer object for this type printer."
+        return self._recognizer(self.template, self.name, self.targ1)
+
+def add_one_type_printer(obj, template, name, targ1 = None):
+    printer = FilteringTypePrinter('std::' + template, 'std::' + name, targ1)
+    gdb.types.register_type_printer(obj, printer)
+    if _versioned_namespace and not '__cxx11' in template:
+        ns = 'std::' + _versioned_namespace
+        printer = FilteringTypePrinter(ns + template, ns + name, targ1)
+        gdb.types.register_type_printer(obj, printer)
+
+def register_type_printers(obj):
+    global _use_type_printing
+
+    if not _use_type_printing:
+        return
+
+    # Add type printers for typedefs std::string, std::wstring etc.
+    for ch in (('', 'char'),
+               ('w', 'wchar_t'),
+               ('u8', 'char8_t'),
+               ('u16', 'char16_t'),
+               ('u32', 'char32_t')):
+        add_one_type_printer(obj, 'basic_string', ch[0] + 'string', ch[1])
+        add_one_type_printer(obj, '__cxx11::basic_string', ch[0] + 'string', ch[1])
+        # Typedefs for __cxx11::basic_string used to be in namespace __cxx11:
+        add_one_type_printer(obj, '__cxx11::basic_string',
+                             '__cxx11::' + ch[0] + 'string', ch[1])
+        add_one_type_printer(obj, 'basic_string_view', ch[0] + 'string_view', ch[1])
+
+    # Add type printers for typedefs std::istream, std::wistream etc.
+    for ch in (('', 'char'), ('w', 'wchar_t')):
+        for x in ('ios', 'streambuf', 'istream', 'ostream', 'iostream',
+                  'filebuf', 'ifstream', 'ofstream', 'fstream'):
+            add_one_type_printer(obj, 'basic_' + x, ch[0] + x, ch[1])
+        for x in ('stringbuf', 'istringstream', 'ostringstream',
+                  'stringstream'):
+            add_one_type_printer(obj, 'basic_' + x, ch[0] + x, ch[1])
+            # <sstream> types are in __cxx11 namespace, but typedefs aren't:
+            add_one_type_printer(obj, '__cxx11::basic_' + x, ch[0] + x, ch[1])
+
+    # Add type printers for typedefs regex, wregex, cmatch, wcmatch etc.
+    for abi in ('', '__cxx11::'):
+        for ch in (('', 'char'), ('w', 'wchar_t')):
+            add_one_type_printer(obj, abi + 'basic_regex', abi + ch[0] + 'regex', ch[1])
+        for ch in ('c', 's', 'wc', 'ws'):
+            add_one_type_printer(obj, abi + 'match_results', abi + ch + 'match')
+            for x in ('sub_match', 'regex_iterator', 'regex_token_iterator'):
+                add_one_type_printer(obj, abi + x, abi + ch + x)
+
+    # Note that we can't have a printer for std::wstreampos, because
+    # it is the same type as std::streampos.
+    add_one_type_printer(obj, 'fpos', 'streampos')
+
+    # Add type printers for <chrono> typedefs.
+    for dur in ('nanoseconds', 'microseconds', 'milliseconds',
+                'seconds', 'minutes', 'hours'):
+        add_one_type_printer(obj, 'duration', dur)
+
+    # Add type printers for <random> typedefs.
+    add_one_type_printer(obj, 'linear_congruential_engine', 'minstd_rand0')
+    add_one_type_printer(obj, 'linear_congruential_engine', 'minstd_rand')
+    add_one_type_printer(obj, 'mersenne_twister_engine', 'mt19937')
+    add_one_type_printer(obj, 'mersenne_twister_engine', 'mt19937_64')
+    add_one_type_printer(obj, 'subtract_with_carry_engine', 'ranlux24_base')
+    add_one_type_printer(obj, 'subtract_with_carry_engine', 'ranlux48_base')
+    add_one_type_printer(obj, 'discard_block_engine', 'ranlux24')
+    add_one_type_printer(obj, 'discard_block_engine', 'ranlux48')
+    add_one_type_printer(obj, 'shuffle_order_engine', 'knuth_b')
+
+    # Add type printers for experimental::basic_string_view typedefs.
+    ns = 'experimental::fundamentals_v1::'
+    for ch in (('', 'char'),
+               ('w', 'wchar_t'),
+               ('u8', 'char8_t'),
+               ('u16', 'char16_t'),
+               ('u32', 'char32_t')):
+        add_one_type_printer(obj, ns + 'basic_string_view',
+                             ns + ch[0] + 'string_view', ch[1])
+
+    # Do not show defaulted template arguments in class templates.
+    add_one_template_type_printer(obj, 'unique_ptr',
+            { 1: 'std::default_delete<{0}>' })
+    add_one_template_type_printer(obj, 'deque', { 1: 'std::allocator<{0}>'})
+    add_one_template_type_printer(obj, 'forward_list', { 1: 'std::allocator<{0}>'})
+    add_one_template_type_printer(obj, 'list', { 1: 'std::allocator<{0}>'})
+    add_one_template_type_printer(obj, '__cxx11::list', { 1: 'std::allocator<{0}>'})
+    add_one_template_type_printer(obj, 'vector', { 1: 'std::allocator<{0}>'})
+    add_one_template_type_printer(obj, 'map',
+            { 2: 'std::less<{0}>',
+              3: 'std::allocator<std::pair<{0} const, {1}>>' })
+    add_one_template_type_printer(obj, 'multimap',
+            { 2: 'std::less<{0}>',
+              3: 'std::allocator<std::pair<{0} const, {1}>>' })
+    add_one_template_type_printer(obj, 'set',
+            { 1: 'std::less<{0}>', 2: 'std::allocator<{0}>' })
+    add_one_template_type_printer(obj, 'multiset',
+            { 1: 'std::less<{0}>', 2: 'std::allocator<{0}>' })
+    add_one_template_type_printer(obj, 'unordered_map',
+            { 2: 'std::hash<{0}>',
+              3: 'std::equal_to<{0}>',
+              4: 'std::allocator<std::pair<{0} const, {1}>>'})
+    add_one_template_type_printer(obj, 'unordered_multimap',
+            { 2: 'std::hash<{0}>',
+              3: 'std::equal_to<{0}>',
+              4: 'std::allocator<std::pair<{0} const, {1}>>'})
+    add_one_template_type_printer(obj, 'unordered_set',
+            { 1: 'std::hash<{0}>',
+              2: 'std::equal_to<{0}>',
+              3: 'std::allocator<{0}>'})
+    add_one_template_type_printer(obj, 'unordered_multiset',
+            { 1: 'std::hash<{0}>',
+              2: 'std::equal_to<{0}>',
+              3: 'std::allocator<{0}>'})
+
+def register_libstdcxx_printers (obj):
+    "Register libstdc++ pretty-printers with objfile Obj."
+
+    global _use_gdb_pp
+    global libstdcxx_printer
+
+    if _use_gdb_pp:
+        gdb.printing.register_pretty_printer(obj, libstdcxx_printer)
+    else:
+        if obj is None:
+            obj = gdb
+        obj.pretty_printers.append(libstdcxx_printer)
+
+    register_type_printers(obj)
+
+def build_libstdcxx_dictionary ():
+    global libstdcxx_printer
+
+    libstdcxx_printer = Printer("libstdc++-v6")
+
+    # libstdc++ objects requiring pretty-printing.
+    # In order from:
+    # http://gcc.gnu.org/onlinedocs/libstdc++/latest-doxygen/a01847.html
+    libstdcxx_printer.add_version('std::', 'basic_string', StdStringPrinter)
+    libstdcxx_printer.add_version('std::__cxx11::', 'basic_string', StdStringPrinter)
+    libstdcxx_printer.add_container('std::', 'bitset', StdBitsetPrinter)
+    libstdcxx_printer.add_container('std::', 'deque', StdDequePrinter)
+    libstdcxx_printer.add_container('std::', 'list', StdListPrinter)
+    libstdcxx_printer.add_container('std::__cxx11::', 'list', StdListPrinter)
+    libstdcxx_printer.add_container('std::', 'map', StdMapPrinter)
+    libstdcxx_printer.add_container('std::', 'multimap', StdMapPrinter)
+    libstdcxx_printer.add_container('std::', 'multiset', StdSetPrinter)
+    libstdcxx_printer.add_version('std::', 'pair', StdPairPrinter)
+    libstdcxx_printer.add_version('std::', 'priority_queue',
+                                  StdStackOrQueuePrinter)
+    libstdcxx_printer.add_version('std::', 'queue', StdStackOrQueuePrinter)
+    libstdcxx_printer.add_version('std::', 'tuple', StdTuplePrinter)
+    libstdcxx_printer.add_container('std::', 'set', StdSetPrinter)
+    libstdcxx_printer.add_version('std::', 'stack', StdStackOrQueuePrinter)
+    libstdcxx_printer.add_version('std::', 'unique_ptr', UniquePointerPrinter)
+    libstdcxx_printer.add_container('std::', 'vector', StdVectorPrinter)
+    # vector<bool>
+
+    if hasattr(gdb.Value, 'dynamic_type'):
+        libstdcxx_printer.add_version('std::', 'error_code',
+                                      StdErrorCodePrinter)
+        libstdcxx_printer.add_version('std::', 'error_condition',
+                                      StdErrorCodePrinter)
+
+    # Printer registrations for classes compiled with -D_GLIBCXX_DEBUG.
+    libstdcxx_printer.add('std::__debug::bitset', StdBitsetPrinter)
+    libstdcxx_printer.add('std::__debug::deque', StdDequePrinter)
+    libstdcxx_printer.add('std::__debug::list', StdListPrinter)
+    libstdcxx_printer.add('std::__debug::map', StdMapPrinter)
+    libstdcxx_printer.add('std::__debug::multimap', StdMapPrinter)
+    libstdcxx_printer.add('std::__debug::multiset', StdSetPrinter)
+    libstdcxx_printer.add('std::__debug::set', StdSetPrinter)
+    libstdcxx_printer.add('std::__debug::vector', StdVectorPrinter)
+
+    # These are the TR1 and C++11 printers.
+    # For array - the default GDB pretty-printer seems reasonable.
+    libstdcxx_printer.add_version('std::', 'shared_ptr', SharedPointerPrinter)
+    libstdcxx_printer.add_version('std::', 'weak_ptr', SharedPointerPrinter)
+    libstdcxx_printer.add_container('std::', 'unordered_map',
+                                    Tr1UnorderedMapPrinter)
+    libstdcxx_printer.add_container('std::', 'unordered_set',
+                                    Tr1UnorderedSetPrinter)
+    libstdcxx_printer.add_container('std::', 'unordered_multimap',
+                                    Tr1UnorderedMapPrinter)
+    libstdcxx_printer.add_container('std::', 'unordered_multiset',
+                                    Tr1UnorderedSetPrinter)
+    libstdcxx_printer.add_container('std::', 'forward_list',
+                                    StdForwardListPrinter)
+
+    libstdcxx_printer.add_version('std::tr1::', 'shared_ptr', SharedPointerPrinter)
+    libstdcxx_printer.add_version('std::tr1::', 'weak_ptr', SharedPointerPrinter)
+    libstdcxx_printer.add_version('std::tr1::', 'unordered_map',
+                                  Tr1UnorderedMapPrinter)
+    libstdcxx_printer.add_version('std::tr1::', 'unordered_set',
+                                  Tr1UnorderedSetPrinter)
+    libstdcxx_printer.add_version('std::tr1::', 'unordered_multimap',
+                                  Tr1UnorderedMapPrinter)
+    libstdcxx_printer.add_version('std::tr1::', 'unordered_multiset',
+                                  Tr1UnorderedSetPrinter)
+
+    libstdcxx_printer.add_version('std::', 'initializer_list',
+                                  StdInitializerListPrinter)
+    libstdcxx_printer.add_version('std::', 'atomic', StdAtomicPrinter)
+
+    # std::regex components
+    libstdcxx_printer.add_version('std::__detail::', '_State',
+                                  StdRegexStatePrinter)
+
+    # These are the C++11 printer registrations for -D_GLIBCXX_DEBUG cases.
+    # The tr1 namespace containers do not have any debug equivalents,
+    # so do not register printers for them.
+    libstdcxx_printer.add('std::__debug::unordered_map',
+                          Tr1UnorderedMapPrinter)
+    libstdcxx_printer.add('std::__debug::unordered_set',
+                          Tr1UnorderedSetPrinter)
+    libstdcxx_printer.add('std::__debug::unordered_multimap',
+                          Tr1UnorderedMapPrinter)
+    libstdcxx_printer.add('std::__debug::unordered_multiset',
+                          Tr1UnorderedSetPrinter)
+    libstdcxx_printer.add('std::__debug::forward_list',
+                          StdForwardListPrinter)
+
+    # Library Fundamentals TS components
+    libstdcxx_printer.add_version('std::experimental::fundamentals_v1::',
+                                  'any', StdExpAnyPrinter)
+    libstdcxx_printer.add_version('std::experimental::fundamentals_v1::',
+                                  'optional', StdExpOptionalPrinter)
+    libstdcxx_printer.add_version('std::experimental::fundamentals_v1::',
+                                  'basic_string_view', StdExpStringViewPrinter)
+    # Filesystem TS components
+    libstdcxx_printer.add_version('std::experimental::filesystem::v1::',
+                                  'path', StdExpPathPrinter)
+    libstdcxx_printer.add_version('std::experimental::filesystem::v1::__cxx11::',
+                                  'path', StdExpPathPrinter)
+    libstdcxx_printer.add_version('std::filesystem::',
+                                  'path', StdPathPrinter)
+    libstdcxx_printer.add_version('std::filesystem::__cxx11::',
+                                  'path', StdPathPrinter)
+
+    # C++17 components
+    libstdcxx_printer.add_version('std::',
+                                  'any', StdExpAnyPrinter)
+    libstdcxx_printer.add_version('std::',
+                                  'optional', StdExpOptionalPrinter)
+    libstdcxx_printer.add_version('std::',
+                                  'basic_string_view', StdExpStringViewPrinter)
+    libstdcxx_printer.add_version('std::',
+                                  'variant', StdVariantPrinter)
+    libstdcxx_printer.add_version('std::',
+                                  '_Node_handle', StdNodeHandlePrinter)
+
+    # C++20 components
+    libstdcxx_printer.add_version('std::', 'partial_ordering', StdCmpCatPrinter)
+    libstdcxx_printer.add_version('std::', 'weak_ordering', StdCmpCatPrinter)
+    libstdcxx_printer.add_version('std::', 'strong_ordering', StdCmpCatPrinter)
+    libstdcxx_printer.add_version('std::', 'span', StdSpanPrinter)
+
+    # Extensions.
+    libstdcxx_printer.add_version('__gnu_cxx::', 'slist', StdSlistPrinter)
+
+    if True:
+        # These shouldn't be necessary, if GDB "print *i" worked.
+        # But it often doesn't, so here they are.
+        libstdcxx_printer.add_container('std::', '_List_iterator',
+                                        StdListIteratorPrinter)
+        libstdcxx_printer.add_container('std::', '_List_const_iterator',
+                                        StdListIteratorPrinter)
+        libstdcxx_printer.add_version('std::', '_Rb_tree_iterator',
+                                      StdRbtreeIteratorPrinter)
+        libstdcxx_printer.add_version('std::', '_Rb_tree_const_iterator',
+                                      StdRbtreeIteratorPrinter)
+        libstdcxx_printer.add_container('std::', '_Deque_iterator',
+                                        StdDequeIteratorPrinter)
+        libstdcxx_printer.add_container('std::', '_Deque_const_iterator',
+                                        StdDequeIteratorPrinter)
+        libstdcxx_printer.add_version('__gnu_cxx::', '__normal_iterator',
+                                      StdVectorIteratorPrinter)
+        libstdcxx_printer.add_container('std::', '_Bit_iterator',
+                                      StdBitIteratorPrinter)
+        libstdcxx_printer.add_container('std::', '_Bit_const_iterator',
+                                      StdBitIteratorPrinter)
+        libstdcxx_printer.add_container('std::', '_Bit_reference',
+                                      StdBitReferencePrinter)
+        libstdcxx_printer.add_version('__gnu_cxx::', '_Slist_iterator',
+                                      StdSlistIteratorPrinter)
+        libstdcxx_printer.add_container('std::', '_Fwd_list_iterator',
+                                        StdFwdListIteratorPrinter)
+        libstdcxx_printer.add_container('std::', '_Fwd_list_const_iterator',
+                                        StdFwdListIteratorPrinter)
+
+        # Debug (compiled with -D_GLIBCXX_DEBUG) printer
+        # registrations.
+        libstdcxx_printer.add('__gnu_debug::_Safe_iterator',
+                              StdDebugIteratorPrinter)
+
+build_libstdcxx_dictionary ()
-- 
2.40.1


                 reply	other threads:[~2023-06-19 11:47 UTC|newest]

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