SERVER-26634 GDB Pretty-Printers and Commands

2 files changed, 73 insertions, 67 deletions

diff --git a/.gdbinit b/.gdbinit
index bda63f0b508..d82d81f02ba 100644
--- a/.gdbinit
+++ b/.gdbinit
@@ -1,4 +1,3 @@
-
 # Print the full stack trace on python exceptions to aid debugging
 set python print-stack full
 
diff --git a/buildscripts/gdb/mongo.py b/buildscripts/gdb/mongo.py
index 54578d1da58..e6f4209bb5e 100644
--- a/buildscripts/gdb/mongo.py
+++ b/buildscripts/gdb/mongo.py
@@ -25,6 +25,8 @@ def get_unique_ptr(obj):
 # Pretty-Printers
 #
 ###################################################################################################
+
+
 class StatusPrinter(object):
     """Pretty-printer for mongo::Status"""
     OK = 0  # ErrorCodes::OK
@@ -33,10 +35,10 @@ class StatusPrinter(object):
         self.val = val
 
     def to_string(self):
-        code = self.code()
-        if code == StatusPrinter.OK:
+        if not self.val['_error']:
             return 'Status::OK()'
 
+        code = self.val['_error']['code']
         # Remove the mongo::ErrorCodes:: prefix. Does nothing if not a real ErrorCode.
         code = str(code).split('::')[-1]
 
@@ -44,47 +46,37 @@ class StatusPrinter(object):
         location = info['location']
         reason = info['reason']
         if location:
-            return 'Status(%s, %s, %s)'%(code, reason, location)
+            return 'Status(%s, %s, %s)' % (code, reason, location)
         else:
-            return 'Status(%s, %s)'%(code, reason)
-
-    def code(self):
-        if not self.val['_error']:
-            return StatusPrinter.OK
-        return self.val['_error'].dereference()['code']
+            return 'Status(%s, %s)' % (code, reason)
 
 
 class StatusWithPrinter:
     """Pretty-printer for mongo::StatusWith<>"""
-    OK = 0  # ErrorCodes::OK
-
     def __init__(self, val):
         self.val = val
 
     def to_string(self):
-        code = self.code()
-        if code == StatusPrinter.OK:
-            return 'StatusWith(%s, %s)'%(code, self.val['_t'])
+        if not self.val['_status']['_error']:
+            return 'StatusWith(OK, %s)' % (self.val['_t'])
+
+        code = self.val['_status']['_error']['code']
 
         # Remove the mongo::ErrorCodes:: prefix. Does nothing if not a real ErrorCode.
         code = str(code).split('::')[-1]
 
         info = self.val['_status']['_error'].dereference()
-        location = info['_status']['location']
-        reason = info['_status']['reason']
+        location = info['location']
+        reason = info['reason']
         if location:
-            return 'StatusWith(%s, %s, %s)'%(code, reason, location)
+            return 'StatusWith(%s, %s, %s)' % (code, reason, location)
         else:
-            return 'StatusWith(%s, %s)'%(code, reason)
-
-    def code(self):
-        if not self.val['_status']['_error']:
-            return StatusWithPrinter.OK
-        return self.val['_status'].dereference()['code']
+            return 'StatusWith(%s, %s)' % (code, reason)
 
 
 class StringDataPrinter:
     """Pretty-printer for mongo::StringData"""
+
     def __init__(self, val):
         self.val = val
 
@@ -96,11 +88,12 @@ class StringDataPrinter:
         if size == -1:
             return self.val['_data'].lazy_string()
         else:
-            return self.val['_data'].lazy_string(length = size)
+            return self.val['_data'].lazy_string(length=size)
 
 
 class BSONObjPrinter:
     """Pretty-printer for mongo::BSONObj"""
+
     def __init__(self, val):
         self.val = val
         self.ptr = self.val['_objdata'].cast(gdb.lookup_type('void').pointer())
@@ -110,6 +103,9 @@ class BSONObjPrinter:
         return 'map'
 
     def children(self):
+        if not bson:
+            return
+
         inferior = gdb.selected_inferior()
         buf = bytes(inferior.read_memory(self.ptr, self.size))
         options = CodecOptions(document_class=collections.OrderedDict)
@@ -123,14 +119,13 @@ class BSONObjPrinter:
         ownership = "owned" if self.val['_ownedBuffer']['_buffer']['_holder']['px'] else "unowned"
 
         size = self.size
-        if size < 5 or size > 17*1024*1024:
-            # TODO: print invalid sizes in hex as they may be sentinel bytes.
+        if size < 5 or size > 17 * 1024 * 1024:
             size = hex(size)
 
         if size == 5:
-            return "%s empty BSONObj @ %s"%(ownership, self.ptr)
+            return "%s empty BSONObj @ %s" % (ownership, self.ptr)
         else:
-            return "%s BSONObj %s bytes @ %s"%(ownership, size, self.ptr)
+            return "%s BSONObj %s bytes @ %s" % (ownership, size, self.ptr)
 
 
 class UnorderedFastKeyTablePrinter:
@@ -144,12 +139,12 @@ class UnorderedFastKeyTablePrinter:
         valueType = gdb.lookup_type(valueTypeName).target()
         self.valueTypePtr = valueType.pointer()
 
-    def display_hint (self):
+    def display_hint(self):
         return 'map'
 
     def to_string(self):
         return "UnorderedFastKeyTablePrinter<%s> with %s elems " % (
-                self.val.type.template_argument(0), self.val["_size"])
+            self.val.type.template_argument(0), self.val["_size"])
 
     def children(self):
         cap = self.val["_area"]["_hashMask"] + 1
@@ -182,17 +177,16 @@ class DecorablePrinter:
         self.start = decl_vector["_M_impl"]["_M_start"]
         finish = decl_vector["_M_impl"]["_M_finish"]
         decinfo_t = gdb.lookup_type('mongo::DecorationRegistry::DecorationInfo')
-        self.count = int( (int(finish) - int(self.start)) / decinfo_t.sizeof )
+        self.count = int((int(finish) - int(self.start)) / decinfo_t.sizeof)
 
-    def display_hint (self):
+    def display_hint(self):
         return 'map'
 
     def to_string(self):
         return "Decorable<%s> with %s elems " % (self.val.type.template_argument(0),
-                                               self.count)
+                                                 self.count)
 
     def children(self):
-
         decorationData = get_unique_ptr(self.val["_decorations"]["_decorationData"])
 
         for index in range(self.count):
@@ -216,13 +210,13 @@ class DecorablePrinter:
             type_t = gdb.lookup_type(type_name)
             obj = decorationData[dindex].cast(type_t)
 
-            yield ('key', type_name)
-            yield ('value', obj.address)
+            yield ('key', "%d:%s:%s" % (index, obj.address, type_name))
+            yield ('value', obj)
 
 
 def find_match_brackets(search, opening='<', closing='>'):
     """Returns the index of the closing bracket that matches the first opening bracket.
-       Returns -1 if no last matching bracket is found, i.e. not a a template.
+       Returns -1 if no last matching bracket is found, i.e. not a template.
 
        Example:
          'Foo<T>::iterator<U>''
@@ -232,41 +226,43 @@ def find_match_brackets(search, opening='<', closing='>'):
     if index == -1:
         return -1
 
-    index = index + 1
+    start = index + 1
     count = 1
     str_len = len(search)
-    while index < str_len and count > 0:
+    for index in range(start, str_len):
         c = search[index]
 
-        index = index + 1
         if c == opening:
-            count = count + 1
+            count += 1
         elif c == closing:
-            count = count - 1
+            count -= 1
 
         if count == 0:
-            return index - 1
+            return index
 
     return -1
 
 
 class MongoSubPrettyPrinter(gdb.printing.SubPrettyPrinter):
     """Sub pretty printer managed by the pretty-printer collection"""
-    def __init__(self, name, prefix, printer):
+
+    def __init__(self, name, prefix, is_template, printer):
         super(MongoSubPrettyPrinter, self).__init__(name)
         self.prefix = prefix
         self.printer = printer
+        self.is_template = is_template
 
 
 class MongoPrettyPrinterCollection(gdb.printing.PrettyPrinter):
     """MongoDB-specific printer printer collection that ignores subtypes.
-    It will match 'HashTable<T> but not 'HashTable<T>::iterator' when asked for 'HashTable'
+    It will match 'HashTable<T> but not 'HashTable<T>::iterator' when asked for 'HashTable'.
     """
+
     def __init__(self):
         super(MongoPrettyPrinterCollection, self).__init__("mongo", [])
 
-    def add(self, name, prefix, printer):
-        self.subprinters.append(MongoSubPrettyPrinter(name, prefix, printer))
+    def add(self, name, prefix, is_template, printer):
+        self.subprinters.append(MongoSubPrettyPrinter(name, prefix, is_template, printer))
 
     def __call__(self, val):
 
@@ -283,7 +279,9 @@ class MongoPrettyPrinterCollection(gdb.printing.PrettyPrinter):
         # We do not want HashTable<T>::iterator as an example, just HashTable<T>
         if index == -1 or index + 1 == len(lookup_tag):
             for printer in self.subprinters:
-                if printer.enabled and lookup_tag.find(printer.prefix) == 0:
+                if printer.enabled and (
+                   (printer.is_template and lookup_tag.find(printer.prefix) == 0) or
+                   (not printer.is_template and lookup_tag == printer.prefix)):
                     return printer.printer(val)
 
         return None
@@ -291,13 +289,12 @@ class MongoPrettyPrinterCollection(gdb.printing.PrettyPrinter):
 
 def build_pretty_printer():
     pp = MongoPrettyPrinterCollection()
-    if bson is not None:
-        pp.add('BSONObj', 'mongo::BSONObj', BSONObjPrinter)
-    pp.add('Decorable', 'mongo::Decorable', DecorablePrinter)
-    pp.add('Status', 'mongo::Status', StatusPrinter)
-    pp.add('StatusWith', 'mongo::StatusWith', StatusWithPrinter)
-    pp.add('StringData', 'mongo::StringData', StringDataPrinter)
-    pp.add('UnorderedFastKeyTable', 'mongo::UnorderedFastKeyTable', UnorderedFastKeyTablePrinter)
+    pp.add('BSONObj', 'mongo::BSONObj', False, BSONObjPrinter)
+    pp.add('Decorable', 'mongo::Decorable', True, DecorablePrinter)
+    pp.add('Status', 'mongo::Status', False, StatusPrinter)
+    pp.add('StatusWith', 'mongo::StatusWith', True, StatusWithPrinter)
+    pp.add('StringData', 'mongo::StringData', False, StringDataPrinter)
+    pp.add('UnorderedFastKeyTable', 'mongo::UnorderedFastKeyTable', True, UnorderedFastKeyTablePrinter)
     return pp
 
 ###################################################################################################
@@ -308,6 +305,7 @@ def build_pretty_printer():
 # Dictionary of commands so we can write a help function that describes the MongoDB commands.
 mongo_commands = {}
 
+
 def register_mongo_command(obj, name, command_class):
     """Register a command with no completer as a mongo command"""
     global mongo_commands
@@ -315,15 +313,19 @@ def register_mongo_command(obj, name, command_class):
 
     mongo_commands[name] = obj.__doc__
 
+
 class DumpGlobalServiceContext(gdb.Command):
     """Dump the Global Service Context"""
 
     def __init__(self):
-        register_mongo_command(self, "mongodb-services", gdb.COMMAND_DATA)
+        register_mongo_command(self, "mongodb-service-context", gdb.COMMAND_DATA)
 
     def invoke(self, arg, _from_tty):
         gdb.execute("print *('mongo::(anonymous namespace)::globalServiceContext')")
 
+# Register command
+DumpGlobalServiceContext()
+
 
 class MongoDBAnalyze(gdb.Command):
     """Analyze MongoDB process"""
@@ -347,10 +349,17 @@ class MongoDBAnalyze(gdb.Command):
     def analyze_mongod(self):
         """GDB in-process python supplement"""
 
-        # Call into mongod, and dump the state of lock manager
-        # Note that output will go to mongod's standard output, not the debugger output window
-        gdb.execute("call ('mongo::(anonymous namespace)::globalLockManager').dump()",
-                    from_tty=False, to_string=False)
+        try:
+
+            # Call into mongod, and dump the state of lock manager
+            # Note that output will go to mongod's standard output, not the debugger output window
+            gdb.execute("call ('mongo::(anonymous namespace)::globalLockManager').dump()",
+                        from_tty=False, to_string=False)
+        except gdb.Error as gdberr:
+            print("Ignoring error '%s'" % str(gdberr))
+
+# Register command
+MongoDBAnalyze()
 
 
 class MongoDBHelp(gdb.Command):
@@ -364,9 +373,7 @@ class MongoDBHelp(gdb.Command):
         for key in mongo_commands:
             print("%s - %s" % (key, mongo_commands[key]))
 
-# Initialize Commands
-DumpGlobalServiceContext()
-MongoDBAnalyze()
+# Register command
 MongoDBHelp()
 
 ###################################################################################################
@@ -377,8 +384,8 @@ MongoDBHelp()
 
 # Register pretty-printers, replace existing mongo printers
 gdb.printing.register_pretty_printer(
-        gdb.current_objfile(),
-        build_pretty_printer(),
-        True)
+    gdb.current_objfile(),
+    build_pretty_printer(),
+    True)
 
 print("MongoDB GDB pretty-printers and commands loaded, run 'mongodb-help' for list of commands")