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# Any copyright is dedicated to the Public Domain.
import lldb
from lldbutils import utils
def summarize_string(valobj, internal_dict):
data = valobj.GetChildMemberWithName("mData")
length = valobj.GetChildMemberWithName("mLength").GetValueAsUnsigned(0)
return utils.format_string(data, length)
def summarize_atom(valobj, internal_dict):
target = lldb.debugger.GetSelectedTarget()
length = valobj.GetChildMemberWithName("mLength").GetValueAsUnsigned()
string = target.EvaluateExpression(
"(char16_t*)%s.GetUTF16String()" % valobj.GetName()
)
return utils.format_string(string, length)
class TArraySyntheticChildrenProvider:
def __init__(self, valobj, internal_dict):
self.valobj = valobj
self.header = self.valobj.GetChildMemberWithName("mHdr")
self.element_type = self.valobj.GetType().GetTemplateArgumentType(0)
self.element_size = self.element_type.GetByteSize()
header_size = self.header.GetType().GetPointeeType().GetByteSize()
self.element_base_addr = self.header.GetValueAsUnsigned(0) + header_size
def num_children(self):
return (
self.header.Dereference()
.GetChildMemberWithName("mLength")
.GetValueAsUnsigned(0)
)
def get_child_index(self, name):
try:
index = int(name)
if index >= self.num_children():
return None
# Ideally we'd use the exception type, but it's unclear what that is
# without knowing how to trigger the original exception.
except: # NOQA: E501, E722
pass
return None
def get_child_at_index(self, index):
if index >= self.num_children():
return None
addr = self.element_base_addr + index * self.element_size
return self.valobj.CreateValueFromAddress(
"[%d]" % index, addr, self.element_type
)
def prefcnt(debugger, command, result, dict):
"""Displays the refcount of an object."""
# We handled regular nsISupports-like refcounted objects and cycle collected
# objects.
target = debugger.GetSelectedTarget()
process = target.GetProcess()
thread = process.GetSelectedThread()
frame = thread.GetSelectedFrame()
obj = frame.EvaluateExpression(command)
if obj.GetError().Fail():
print("could not evaluate expression")
return
obj = utils.dereference(obj)
field = obj.GetChildMemberWithName("mRefCnt")
if field.GetError().Fail():
field = obj.GetChildMemberWithName("refCnt")
if field.GetError().Fail():
print("not a refcounted object")
return
refcnt_type = field.GetType().GetCanonicalType().GetName()
if refcnt_type == "nsAutoRefCnt":
print(field.GetChildMemberWithName("mValue").GetValueAsUnsigned(0))
elif refcnt_type == "nsCycleCollectingAutoRefCnt":
print(
field.GetChildMemberWithName("mRefCntAndFlags").GetValueAsUnsigned(0) >> 2
)
elif refcnt_type == "mozilla::ThreadSafeAutoRefCnt":
print(
field.GetChildMemberWithName("mValue")
.GetChildMemberWithName("mValue")
.GetValueAsUnsigned(0)
)
elif refcnt_type == "int": # non-atomic mozilla::RefCounted object
print(field.GetValueAsUnsigned(0))
elif refcnt_type == "mozilla::Atomic<int>": # atomic mozilla::RefCounted object
print(field.GetChildMemberWithName("mValue").GetValueAsUnsigned(0))
else:
print("unknown mRefCnt type " + refcnt_type)
def callfunc(debugger, command, result, dict):
"""Calls a function for which debugger information is unavailable by getting its address
from the symbol table. The function is assumed to return void."""
if "(" not in command:
print("Usage: callfunc your_function(args)")
return
command_parts = command.split("(")
funcname = command_parts[0].strip()
args = command_parts[1]
target = debugger.GetSelectedTarget()
symbols = target.FindFunctions(funcname).symbols
if not symbols:
print('Could not find a function symbol for a function called "%s"' % funcname)
return
sym = symbols[0]
arg_types = "()"
if sym.name and sym.name.startswith(funcname + "("):
arg_types = sym.name[len(funcname) :]
debugger.HandleCommand(
"print ((void(*)%s)0x%0x)(%s"
% (arg_types, sym.addr.GetLoadAddress(target), args)
)
def init(debugger):
debugger.HandleCommand(
"type summary add nsAString -F lldbutils.general.summarize_string"
)
debugger.HandleCommand(
"type summary add nsACString -F lldbutils.general.summarize_string"
)
debugger.HandleCommand(
"type summary add nsFixedString -F lldbutils.general.summarize_string"
)
debugger.HandleCommand(
"type summary add nsFixedCString -F lldbutils.general.summarize_string"
)
debugger.HandleCommand(
"type summary add nsAutoString -F lldbutils.general.summarize_string"
)
debugger.HandleCommand(
"type summary add nsAutoCString -F lldbutils.general.summarize_string"
)
debugger.HandleCommand(
"type summary add nsAtom -F lldbutils.general.summarize_atom"
)
debugger.HandleCommand(
'type synthetic add -x "nsTArray<" -l lldbutils.general.TArraySyntheticChildrenProvider'
)
debugger.HandleCommand(
'type synthetic add -x "AutoTArray<" -l lldbutils.general.TArraySyntheticChildrenProvider' # NOQA: E501
)
debugger.HandleCommand(
'type synthetic add -x "FallibleTArray<" -l lldbutils.general.TArraySyntheticChildrenProvider' # NOQA: E501
)
debugger.HandleCommand(
"command script add -f lldbutils.general.prefcnt -f lldbutils.general.prefcnt prefcnt"
)
debugger.HandleCommand(
"command script add -f lldbutils.general.callfunc -f lldbutils.general.callfunc callfunc"
)