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godot-cpp.natvis debug visualizers #1977

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3d0ad91
copy of godot.natvis from master
van800 Apr 28, 2026
da3c4a3
Remove unused entries (godotengine original types)
van800 Apr 28, 2026
8a9a174
add support for evaluating godot::Variant, godot::Array and godot::Di…
van800 Apr 28, 2026
8648636
improve dictionary presentation
van800 Apr 29, 2026
4d1b17e
update developer notes and reformat file
van800 Apr 29, 2026
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159 changes: 159 additions & 0 deletions natvis/godot-cpp.natvis
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Original file line number Diff line number Diff line change
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<?xml version="1.0" encoding="utf-8"?>
<AutoVisualizer xmlns="http://schemas.microsoft.com/vstudio/debugger/natvis/2010">
<Type Name="godot::String">
<DisplayString>{*reinterpret_cast&lt;void**&gt;(opaque),s32}</DisplayString>
<Expand>
<Item Name="opaque_ptr">*reinterpret_cast&lt;void**&gt;(opaque)</Item>
<Item Name="string">*reinterpret_cast&lt;void**&gt;(opaque),s32</Item>
</Expand>
</Type>

<Type Name="godot::StringName">
<Intrinsic Name="get_data_ptr" Expression="(*reinterpret_cast&lt;const char32_t***&gt;(opaque))[1]" />
<DisplayString Condition="get_data_ptr()">{get_data_ptr(),s32}</DisplayString>
<Expand>
<Item Name="opaque_ptr">*reinterpret_cast&lt;void**&gt;(opaque)</Item>
<Item Name="cname">get_data_ptr(),s32</Item>
</Expand>
</Type>

<!-- Development notes: At the current state no AI can directly generate a natvis entry for each `godot::` type.
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The testdata used for evaluation https://github.com/JetBrains/godot-support/wiki/Developing-godot%E2%80%90cpp.natvis
The change of the memory layout would require adjustments of the natvis

Approach:
1. For each type, inspect `opaque` bytes in LLDB using `memory read -size 8 -count N -format address` on
the address stored in opaque (e.g. `*(void**)demo_type.opaque`) to map the actual field layout.
2. Verify specific field values match known test data (e.g. array size=1, int value=42, string content).
3. Write natvis expressions only after the field offsets are confirmed.

Evaluator constraints (JetBrains natvis engine, I haven't checked anything else):
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- Supports: reinterpret_cast, pointer arithmetic on built-in types, array indexing ([n]), Intrinsics
- Does NOT support: calling member functions (e.g. size())
- Nested type visualizers work: `{*(godot::String*)(opaque+8)}` delegates to the String natvis entry

Patterns used:
- Opaque wrapper types (String, StringName, Array, Dictionary, ...): cast opaque slice to the
godot-cpp type pointer — `*(godot::TypeName*)(opaque+N)` — and let that type's natvis handle display
- Engine heap-allocated types stored as pointer (Transform2D, AABB, Basis, ...): double-deref —
`**(godot::TypeName**)(opaque+N)`
- Engine internals without a godot-cpp wrapper (ArrayPrivate, CowData, HashMap): use raw
reinterpret_cast + index arithmetic, document offsets with a comment verified by LLDB

Future upcomming improvements:
- JetBrains natvis support is going to become x-plat https://youtrack.jetbrains.com/issue/CPP-35297
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-->

<!-- opaque[0..7] holds ArrayPrivate*. Dereference as unsigned long long* to read ArrayPrivate
fields as 8-byte slots: [0]=refcount, [1]=unknown, [2]=_cowdata._ptr, [3]=read_only, ...
Index [2] reaches _cowdata._ptr at offset +16 (verified by LLDB memory dump).
Cast _ptr to unsigned long long* so [-1] reads the CowData element count 8 bytes before data. -->
<Type Name="godot::Array">
<Intrinsic Name="_cow" Expression="(unsigned long long*)(*reinterpret_cast&lt;unsigned long long**&gt;(opaque))[2]" />
<DisplayString Condition="!*reinterpret_cast&lt;void**&gt;(opaque) || !_cow()">{{empty}}</DisplayString>
<DisplayString>{{size={_cow()[-1]}}}</DisplayString>
<Expand>
<Item Name="[size]">_cow()[-1]</Item>
<ArrayItems>
<Size>_cow()[-1]</Size>
<ValuePointer>(godot::Variant*)_cow()</ValuePointer>
</ArrayItems>
</Expand>
</Type>

<!-- DictionaryPrivate layout (verified by LLDB console):
[refcount(4)][unknown(4)][read_only(8)][HashMap at +16]
HashMap: [_elements(8)][unknown(8)][_head(8)][_last(8)][_capacity_index(4)][_num_elements(4)]
HashMapElement: [next(8)][prev(8)][key:Variant(24)][value:Variant(24)] -->
<Type Name="godot::Dictionary">
<Intrinsic Name="_p" Expression="*reinterpret_cast&lt;unsigned char**&gt;(opaque)" />
<Intrinsic Name="_size" Expression="*(unsigned int*)(_p() + 52)" />
<Intrinsic Name="_head" Expression="*reinterpret_cast&lt;unsigned char**&gt;(_p() + 32)" />
<DisplayString Condition="!_p()">{{empty}}</DisplayString>
<DisplayString>{{size={_size()}}}</DisplayString>
<Expand>
<Item Name="[size]">_size()</Item>
<CustomListItems MaxItemsPerView="5000">
<Variable Name="elem" InitialValue="(unsigned char*)_head()"/>
<Variable Name="idx" InitialValue="0"/>
<Loop Condition="elem != 0">
<Item Name="[{idx}].key">*(godot::Variant*)(elem + 16)</Item>
<Item Name="[{idx}].value">*(godot::Variant*)(elem + 40)</Item>
<Exec>elem = *(unsigned char**)elem</Exec>
<Exec>idx++</Exec>
</Loop>
</CustomListItems>
</Expand>
</Type>

<!-- Variant::Type enum:
NIL=0 BOOL=1 INT=2 FLOAT=3 STRING=4 VECTOR2=5 VECTOR2I=6 RECT2=7 RECT2I=8
VECTOR3=9 VECTOR3I=10 TRANSFORM2D=11 VECTOR4=12 VECTOR4I=13 PLANE=14
QUATERNION=15 AABB=16 BASIS=17 TRANSFORM3D=18 PROJECTION=19 COLOR=20
STRING_NAME=21 NODE_PATH=22 RID=23 OBJECT=24 CALLABLE=25 SIGNAL=26
DICTIONARY=27 ARRAY=28
Layout: opaque[0..3]=type(int32), opaque[4..7]=pad, opaque[8..23]=_data union -->
<Type Name="godot::Variant">
<Intrinsic Name="_type" Expression="*reinterpret_cast&lt;int*&gt;(opaque)" />
<DisplayString Condition="_type() == 0">nil</DisplayString>
<DisplayString Condition="_type() == 1">{*reinterpret_cast&lt;bool*&gt;(opaque+8)}</DisplayString>
<DisplayString Condition="_type() == 2">{*reinterpret_cast&lt;long long*&gt;(opaque+8)}</DisplayString>
<DisplayString Condition="_type() == 3">{*reinterpret_cast&lt;double*&gt;(opaque+8)}</DisplayString>
<!-- inline types: stored directly in _data._mem at opaque+8 -->
<DisplayString Condition="_type() == 4">{*(godot::String*)(opaque+8)}</DisplayString>
<DisplayString Condition="_type() == 5">{*(godot::Vector2*)(opaque+8)}</DisplayString>
<DisplayString Condition="_type() == 6">{*(godot::Vector2i*)(opaque+8)}</DisplayString>
<DisplayString Condition="_type() == 7">{*(godot::Rect2*)(opaque+8)}</DisplayString>
<DisplayString Condition="_type() == 8">{*(godot::Rect2i*)(opaque+8)}</DisplayString>
<DisplayString Condition="_type() == 9">{*(godot::Vector3*)(opaque+8)}</DisplayString>
<DisplayString Condition="_type() == 10">{*(godot::Vector3i*)(opaque+8)}</DisplayString>
<DisplayString Condition="_type() == 12">{*(godot::Vector4*)(opaque+8)}</DisplayString>
<DisplayString Condition="_type() == 13">{*(godot::Vector4i*)(opaque+8)}</DisplayString>
<DisplayString Condition="_type() == 14">{*(godot::Plane*)(opaque+8)}</DisplayString>
<DisplayString Condition="_type() == 15">{*(godot::Quaternion*)(opaque+8)}</DisplayString>
<DisplayString Condition="_type() == 20">{*(godot::Color*)(opaque+8)}</DisplayString>
<DisplayString Condition="_type() == 21">{*(godot::StringName*)(opaque+8)}</DisplayString>
<DisplayString Condition="_type() == 22">{*(godot::NodePath*)(opaque+8)}</DisplayString>
<DisplayString Condition="_type() == 23">{*(godot::RID*)(opaque+8)}</DisplayString>
<DisplayString Condition="_type() == 25">{*(godot::Callable*)(opaque+8)}</DisplayString>
<DisplayString Condition="_type() == 26">{*(godot::Signal*)(opaque+8)}</DisplayString>
<DisplayString Condition="_type() == 27">{*(godot::Dictionary*)(opaque+8)}</DisplayString>
<DisplayString Condition="_type() == 28">{*(godot::Array*)(opaque+8)}</DisplayString>
<!-- heap-allocated types: opaque+8 holds a pointer, double-deref required -->
<DisplayString Condition="_type() == 11">{**(godot::Transform2D**)(opaque+8)}</DisplayString>
<DisplayString Condition="_type() == 16">{**(godot::AABB**)(opaque+8)}</DisplayString>
<DisplayString Condition="_type() == 17">{**(godot::Basis**)(opaque+8)}</DisplayString>
<DisplayString Condition="_type() == 18">{**(godot::Transform3D**)(opaque+8)}</DisplayString>
<DisplayString Condition="_type() == 19">{**(godot::Projection**)(opaque+8)}</DisplayString>
<!-- OBJECT: opaque+8=ObjectID, opaque+16=Object* -->
<DisplayString Condition="_type() == 24">Object(id={*reinterpret_cast&lt;unsigned long long*&gt;(opaque+8)})</DisplayString>
<DisplayString>{{type={_type()}}}</DisplayString>
<Expand>
<Item Name="[type]">_type()</Item>
<ExpandedItem Condition="_type() == 4">*(godot::String*)(opaque+8)</ExpandedItem>
<ExpandedItem Condition="_type() == 5">*(godot::Vector2*)(opaque+8)</ExpandedItem>
<ExpandedItem Condition="_type() == 6">*(godot::Vector2i*)(opaque+8)</ExpandedItem>
<ExpandedItem Condition="_type() == 7">*(godot::Rect2*)(opaque+8)</ExpandedItem>
<ExpandedItem Condition="_type() == 8">*(godot::Rect2i*)(opaque+8)</ExpandedItem>
<ExpandedItem Condition="_type() == 9">*(godot::Vector3*)(opaque+8)</ExpandedItem>
<ExpandedItem Condition="_type() == 10">*(godot::Vector3i*)(opaque+8)</ExpandedItem>
<ExpandedItem Condition="_type() == 11">**(godot::Transform2D**)(opaque+8)</ExpandedItem>
<ExpandedItem Condition="_type() == 12">*(godot::Vector4*)(opaque+8)</ExpandedItem>
<ExpandedItem Condition="_type() == 13">*(godot::Vector4i*)(opaque+8)</ExpandedItem>
<ExpandedItem Condition="_type() == 14">*(godot::Plane*)(opaque+8)</ExpandedItem>
<ExpandedItem Condition="_type() == 15">*(godot::Quaternion*)(opaque+8)</ExpandedItem>
<ExpandedItem Condition="_type() == 16">**(godot::AABB**)(opaque+8)</ExpandedItem>
<ExpandedItem Condition="_type() == 17">**(godot::Basis**)(opaque+8)</ExpandedItem>
<ExpandedItem Condition="_type() == 18">**(godot::Transform3D**)(opaque+8)</ExpandedItem>
<ExpandedItem Condition="_type() == 19">**(godot::Projection**)(opaque+8)</ExpandedItem>
<ExpandedItem Condition="_type() == 20">*(godot::Color*)(opaque+8)</ExpandedItem>
<ExpandedItem Condition="_type() == 21">*(godot::StringName*)(opaque+8)</ExpandedItem>
<ExpandedItem Condition="_type() == 22">*(godot::NodePath*)(opaque+8)</ExpandedItem>
<ExpandedItem Condition="_type() == 23">*(godot::RID*)(opaque+8)</ExpandedItem>
<ExpandedItem Condition="_type() == 25">*(godot::Callable*)(opaque+8)</ExpandedItem>
<ExpandedItem Condition="_type() == 26">*(godot::Signal*)(opaque+8)</ExpandedItem>
<ExpandedItem Condition="_type() == 27">*(godot::Dictionary*)(opaque+8)</ExpandedItem>
<ExpandedItem Condition="_type() == 28">*(godot::Array*)(opaque+8)</ExpandedItem>
</Expand>
</Type>
</AutoVisualizer>
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