From 087fbf08f600d061de7531a14c496145262e7319 Mon Sep 17 00:00:00 2001 From: David Mentler Date: Mon, 22 Sep 2025 12:20:15 +0200 Subject: [PATCH] Added type formatters for the LLDB debuggers (e.g. Xcode) (#8950) --- misc/debuggers/README.txt | 4 + misc/debuggers/imgui_lldb.py | 187 +++++++++++++++++++++++++++++++++++ 2 files changed, 191 insertions(+) create mode 100644 misc/debuggers/imgui_lldb.py diff --git a/misc/debuggers/README.txt b/misc/debuggers/README.txt index 3f4ba83e3..77a78b9e5 100644 --- a/misc/debuggers/README.txt +++ b/misc/debuggers/README.txt @@ -14,3 +14,7 @@ imgui.natvis With this, types like ImVector<> will be displayed nicely in the debugger. (read comments inside file for details) +imgui_lldb.py + LLDB: synthetic children provider and summaries for Dear ImGui types. + With this, types like ImVector<> will be displayed nicely in the debugger. + (read comments inside file for details) diff --git a/misc/debuggers/imgui_lldb.py b/misc/debuggers/imgui_lldb.py new file mode 100644 index 000000000..336d3f513 --- /dev/null +++ b/misc/debuggers/imgui_lldb.py @@ -0,0 +1,187 @@ +# This file implements synthetic children providers and summaries for various ImGui types for LLDB. +# +# Useful links/documentation related to the feature: +# - https://lldb.llvm.org/use/variable.html#summary-strings +# - https://lldb.llvm.org/use/variable.html#synthetic-children +# - https://lldb.llvm.org/python_reference/lldb-module.html +# +# To use it in a debug session: +# > (lldb) command script import +# +# Alternatively you may include the above command in your ~/.lldbinit file to have the formatters +# available in all future sessions + +import lldb + +class ArraySynthBase(object): + """ + Helper baseclass aimed to reduce the boilerplate needed for "array-like" containers + """ + + def __init__(self, valobj, internal_dict): + self.valobj = valobj + + def bind_to(self, pointer, size): + array_p = pointer.GetType().GetPointeeType().GetArrayType(size).GetPointerType() + self.array = pointer.Cast(array_p).Dereference() + + def update(self): + self.array = self.valobj + + def num_children(self, max_children): + return self.array.GetNumChildren(max_children) + + def get_child_index(self, name): + return self.array.GetIndexOfChildWithName(name) + + def get_child_at_index(self, index): + return self.array.GetChildAtIndex(index) + + def has_children(self): + return self.array.MightHaveChildren() + + def get_value(self): + return self.array + +class ImVectorSynth(ArraySynthBase): + def update(self): + self.size = self.valobj.GetChildMemberWithName("Size").GetValueAsUnsigned() + self.capacity = self.valobj.GetChildMemberWithName("Capacity").GetValueAsUnsigned() + + data = self.valobj.GetChildMemberWithName("Data") + + self.bind_to(data, self.size) + + def get_summary(self): + return f"Size={self.size} Capacity={self.capacity}" + +class ImSpanSynth(ArraySynthBase): + def update(self): + data = self.valobj.GetChildMemberWithName("Data") + end = self.valobj.GetChildMemberWithName("DataEnd") + + element_size = data.GetType().GetPointeeType().GetByteSize() + array_size = end.GetValueAsUnsigned() - data.GetValueAsUnsigned() + + self.size = int(array_size / element_size) + + self.bind_to(data, self.size) + + def get_summary(self): + return f"Size={self.size}" + +class ImRectSummary(object): + def __init__(self, valobj, internal_dict): + self.valobj = valobj + + def update(self): + pass + + def get_summary(self): + min = self.valobj.GetChildMemberWithName("Min") + max = self.valobj.GetChildMemberWithName("Max") + + minX = float(min.GetChildMemberWithName("x").GetValue()) + minY = float(min.GetChildMemberWithName("y").GetValue()) + + maxX = float(max.GetChildMemberWithName("x").GetValue()) + maxY = float(max.GetChildMemberWithName("y").GetValue()) + + return f"Min=({minX}, {minY}) Max=({maxX}, {maxY}) Size=({maxX - minX}, {maxY - minY})" + +def get_active_enum_flags(valobj): + flag_set = set() + + enum_name = valobj.GetType().GetName() + "_" + enum_type = valobj.GetTarget().FindFirstType(enum_name) + + if not enum_type.IsValid(): + return flag_set + + enum_members = enum_type.GetEnumMembers() + value = valobj.GetValueAsUnsigned() + + for i in range(0, enum_members.GetSize()): + member = enum_members.GetTypeEnumMemberAtIndex(i) + + if value & member.GetValueAsUnsigned(): + flag_set.add(member.GetName().removeprefix(enum_name)) + + return flag_set + +class ImGuiWindowSummary(object): + def __init__(self, valobj, internal_dict): + self.valobj = valobj + + def update(self): + pass + + def get_summary(self): + name = self.valobj.GetChildMemberWithName("Name").GetSummary() + + active = self.valobj.GetChildMemberWithName("Active").GetValueAsUnsigned() != 0 + was_active = self.valobj.GetChildMemberWithName("WasActive").GetValueAsUnsigned() != 0 + hidden = self.valobj.GetChildMemberWithName("Hidden") != 0 + + flags = get_active_enum_flags(self.valobj.GetChildMemberWithName("Flags")) + + active = 1 if active or was_active else 0 + child = 1 if "ChildWindow" in flags else 0 + popup = 1 if "Popup" in flags else 0 + hidden = 1 if hidden else 0 + + return f"Name {name} Active {active} Child {child} Popup {popup} Hidden {hidden}" + + +def __lldb_init_module(debugger, internal_dict): + """ + This function will be automatically called by LLDB when the module is loaded, here + we register the various synthetics/summaries we have build before + """ + + category_name = "imgui" + category = debugger.GetCategory(category_name) + + # Make sure we don't accidentally keep accumulating languages or override the user's + # category enablement in Xcode, where lldb-rpc-server loads this file once for eac + # debugging session + if not category.IsValid(): + category = debugger.CreateCategory(category_name) + category.AddLanguage(lldb.eLanguageTypeC_plus_plus) + category.SetEnabled(True) + + def add_summary(typename, impl): + summary = None + + if isinstance(impl, str): + summary = lldb.SBTypeSummary.CreateWithSummaryString(impl) + summary.SetOptions(lldb.eTypeOptionCascade) + else: + # Unfortunately programmatic summary string generation is an entirely different codepath + # in LLDB. Register a convenient trampoline function which makes it look like it's part + # of the SyntheticChildrenProvider contract + summary = lldb.SBTypeSummary.CreateWithScriptCode(f''' + synth = {impl.__module__}.{impl.__qualname__}(valobj.GetNonSyntheticValue(), internal_dict) + synth.update() + + return synth.get_summary() + ''') + summary.SetOptions(lldb.eTypeOptionCascade | lldb.eTypeOptionFrontEndWantsDereference) + + category.AddTypeSummary(lldb.SBTypeNameSpecifier(typename, True), summary) + + def add_synthetic(typename, impl): + add_summary(typename, impl) + + synthetic = lldb.SBTypeSynthetic.CreateWithClassName(f"{impl.__module__}.{impl.__qualname__}") + synthetic.SetOptions(lldb.eTypeOptionCascade | lldb.eTypeOptionFrontEndWantsDereference) + + category.AddTypeSynthetic(lldb.SBTypeNameSpecifier(typename, True), synthetic) + + add_synthetic("^ImVector<.+>$", ImVectorSynth) + add_synthetic("^ImSpan<.+>$", ImSpanSynth) + + add_summary("^ImVec2$", "x=${var.x} y=${var.y}") + add_summary("^ImVec4$", "x=${var.x} y=${var.y} z=${var.z} w=${var.w}") + add_summary("^ImRect$", ImRectSummary) + add_summary("^ImGuiWindow$", ImGuiWindowSummary)