MobileGL/docs/archive/notes/recovered/wf4/part2.md

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2. The non-pGLContext paths by which a backend reaches frontend objects

pGLContext is the only MG_State:: global the backends touch (§0, "other MG_State globals: 0"). Every other reach is one of the five shapes below. P1 cannot succeed by rewriting only the 278 arrow sites: the accessors return references to live frontend objects, and the backends then call ~200 distinct methods on those objects.

2.1 The one static cache of a frontend pointer

MobileGL/MG_Backend/DirectGLES/DirectGLES.cpp:142-155 — the only place a raw GLContext* is stored across calls:

142:    using FbBindingSlot =
143:        std::remove_reference_t<decltype(MG_State::pGLContext->GetFramebufferBindingSlot(FramebufferTarget::Draw))>;
144:    static const MG_State::GLState::GLContext* g_fbSlotCacheContext = nullptr;
145:    static Array<FbBindingSlot*, SizeT(FramebufferTarget::FramebufferTargetCount)> g_fbSlotCache = {};
146:    static inline FbBindingSlot& GetFramebufferBindingSlotFast(FramebufferTarget target) {
147:        MG_State::GLState::GLContext* ctx = MG_State::pGLContext.get();
148:        if (ctx != g_fbSlotCacheContext) { ... &ctx->GetFramebufferBindingSlot(...) ... }

It caches interior pointers into the GLContext object (the by-value binding-slot members), keyed on the raw context address. Under P1 this cache has no meaning across a pipe boundary — the slots are not addressable from the backend at all. Its five call sites are the hot framebuffer path and each is a GetFramebufferBindingSlot read that the arrow-site table does not list (they read through the cache, not through pGLContext):

call site	enclosing function	verb path	what it reads
DirectGLES/DirectGLES.cpp:1611	SyncNeccessaryTextures	texture op (draw/dispatch)	draw FBO binding slot
DirectGLES/DirectGLES.cpp:1905	SyncCurrentFBO	framebuffer sync	slot for target
DirectGLES/DirectGLES.cpp:2743	SyncCurrentProgram	program/uniform sync	draw FBO binding slot
DirectGLES/DirectGLES.cpp:2858	BindCurrentFBO	framebuffer sync	slot for target
DirectGLES/DirectGLES.cpp:2933	ForceBindCurrentFBO	framebuffer sync	slot for target

Each of those five also reads the slot's version (BindingSlot::GetVersion()) at DirectGLES.cpp:1614, 1917, 2745, 2936 — a value block P1 must carry alongside the handle.

There are no other GLContext&/GLContext* parameters or local aliases anywhere in MG_Backend: grep -rn 'GLContext\s*[&*]' --include=*.cpp --include=*.h returns exactly the one line 144 above once pGLContext matches are excluded.

2.2 SharedPtr<MG_State::GLState::…> in signatures and members (the "handle-ify" surface)

177 lines. The ones that matter structurally are the table-level ones (they are the verb signatures themselves) and the member-level ones (backend containers that own or weakly hold frontend objects across frames).

Table-level (these five GLFunctionsTable entries take frontend objects by handle today):

declaration	file:line
ClearNamedFramebufferfv(const SharedPtr<FramebufferObject>&, …)	BackendObject.h:158
ClearNamedFramebufferfi(const SharedPtr<FramebufferObject>&, …)	BackendObject.h:160
ClearNamedFramebufferiv(const SharedPtr<FramebufferObject>&, …)	BackendObject.h:162
ClearNamedFramebufferuiv(const SharedPtr<FramebufferObject>&, …)	BackendObject.h:164
BlitNamedFramebuffer(const SharedPtr<FramebufferObject>& read, const SharedPtr<FramebufferObject>& draw, …)	BackendObject.h:168-169
GetTextureImage(const SharedPtr<ITextureObject>&, …)	BackendObject.h:186
CopyImageSubData(const CopyImageEndpoint& src, …, const CopyImageEndpoint& dst, …) where CopyImageEndpoint is {SharedPtr<ITextureObject> Texture; SharedPtr<RenderbufferObject> Renderbuffer;}	BackendObject.h:33-38, BackendObject.h:176-180

Their per-backend mirrors: DirectGLES/DirectGLES.h:60,62,64,66,70,71; DirectVulkan/DirectVulkan.h:36,38,40,42,76,77,101; DirectVulkan/Renderer/VulkanRenderer.h:184,186,188,190,195,196,256,1400.

Member-level (backend state that outlives a verb and holds frontend objects):

holder	file:line	what it holds
UniformManager::m_fallbackTexture2D	Renderer/UniformManager.h:305	SharedPtr<ITextureObject> — a synthesised frontend texture the backend itself created
UniformManager::m_fallbackMultisampleTextures	Renderer/UniformManager.h:308	UnorderedMap<Uint32, SharedPtr<ITextureObject>>
UniformManager::m_unboundStorageImageTextures	Renderer/UniformManager.h:317	UnorderedMap<Uint64, SharedPtr<ITextureObject>>
VkClearManager::m_aliveObjects	Renderer/VkClearManager.h:167	unordered_map<TextureIdentity, WeakPtr<ITextureObject>>
VkTextureManager::m_aliveObjects	Renderer/VkTextureManager.h:725	unordered_map<TextureIdentity, WeakPtr<ITextureObject>>
VkRenderPassManager attachment records	Renderer/VkRenderPassManager.h:45,51,330,359	WeakPtr<ITextureObject> / WeakPtr<RenderbufferObject>
VulkanRenderer blit/clear helper programs	Renderer/VulkanRenderer.h:378,379,380,388	SharedPtr<ProgramObject> + two SharedPtr<SamplerObject> the backend constructs itself
DirectGLES raw-depth-fetch sampler	DirectGLES/DirectGLES.cpp:55 (static SharedPtr<SamplerObject> g_rawDepthFetchSamplerState), built at DirectGLES.cpp:150-160	same pattern: backend-authored frontend object

The last two rows are the P1 trap: these are frontend objects created by the backend, so under disaggregation the server has no frontend to create them in. They need either a server-local equivalent or a client-side create call.

2.3 The twin registries and the owner-keyed memos

DirectGLES/Managers.h:271 template <typename StateObject, typename BackendObject> class StateBackendObjectRegistry — hash map keyed on the raw frontend object pointer (using BackendMap = UnorderedMap<StateObject*, Entry>;, Managers.h:284), each Entry holding {BackendPtr backend; StateWeakPtr stateRef;} (Managers.h:280-283). Liveness is decided by entry.stateRef.expired() (Managers.h:318, Managers.h:339).

Six instances, all reached by the draw path:

registry	declared	keyed on
VertexArrayImpl::g_backendVertexArrayObjects	Managers.h:803-804	VertexArrayObject*
TextureImpl::g_backendTextureObjects	Managers.h:1124-1125	ITextureObject*
FramebufferImpl::g_backendFramebufferObjects	Managers.h:1215-1216	FramebufferObject*
PrgramImpl::g_backendProgramObjects	Managers.h:1733-1734	ProgramObject*
SamplerImpl::g_backendSamplerObjects	Managers.h:1833-1834	SamplerObject*
RenderbufferImpl::g_backendRenderbufferObjects	Managers.h:1860-1861	RenderbufferObject*

On top of them, DirectGLES/DirectGLES.cpp:83-115 class TwinLookupMemo — a direct-mapped memo whose slot is {StateObject* key; WeakPtr<StateObject> owner; BackendObject* twin;} (DirectGLES.cpp:100-104), indexed by Fibonacci-hashing the frontend heap address (DirectGLES.cpp:108-112), validated by OwnerEquals (DirectGLES.cpp:62-65, a weak_ptr::owner_before pair test). Three instances: g_vaoTwinLookupMemo (DirectGLES.cpp:122-123), g_programTwinLookupMemo (DirectGLES.cpp:124-125), g_fboTwinLookupMemo (DirectGLES.cpp:130-131); looked up at DirectGLES.cpp:1204, 2767, 2872 and stored at 1212, 2775, 2877.

Both mechanisms are pointer-identity based and cannot survive a process/thread split. P1 has to replace "frontend heap address + weak_ptr owner equality" with the wire handle plus a lifetime id. The good news is that the frontend already exposes exactly that: GetLifetimeId() (§2.4).

2.4 Lifetime-id and version reads (the memo keys P1 must carry over the wire)

39 GetLifetimeId() reads:

object kind	sites
program	DirectGLES/DirectGLES.cpp:3333, 3349; DirectVulkan/DirectVulkan.cpp:163; Renderer/UniformManager.cpp:482, 696, 2272, 2384, 2732; Renderer/VulkanRenderer.cpp:6044, 6484, 6524, 6577, 6648, 6962
texture	Renderer/UniformManager.cpp:656, 1746, 1792; Renderer/VkClearManager.cpp:155, 197, 251, 368, 459; Renderer/VkRenderPassManager.cpp:642; Renderer/VkTextureManager.cpp:235, 733
sampler	Renderer/UniformManager.cpp:654, 1747, 1793
VAO	Renderer/VertexInputStateFactory.cpp:48 (via attr.Buffer, actually a buffer); Renderer/VulkanRenderer.cpp:3552, 6107, 6384, 6965
FBO	Renderer/VkRenderPassManager.cpp:844, 869; Renderer/VulkanRenderer.cpp:6112, 6968
buffer	DirectGLES/Managers.cpp:2678; Renderer/VertexInputStateFactory.cpp:48

36 version reads:

version	sites	what it gates
BindingSlot::GetVersion() (framebuffer slot)	DirectGLES/DirectGLES.cpp:1614, 1917, 2745, 2936	the FBO-sync short-circuit (g_fboSyncedSlotVersions)
BindingSlot::GetVersion() (VAO index-buffer slot)	DirectGLES/Managers.cpp:2307	element-array rebind
BufferObject::GetChangeSerial()	DirectGLES/Managers.cpp:794, 1078, 1151, 1163, 1203, 1238, 1245, 1283, 1468, 1553, 1580, 1581, 2679; Renderer/VkBufferManager.cpp:697; Renderer/VulkanRenderer.cpp:3849	every buffer upload/re-upload decision on both backends
ITextureObject::GetContentVersion()	DirectGLES/Managers.cpp:3649, 3776, 3826, 4731; Managers.h:1012; Renderer/VkTextureManager.cpp:1646, 1755; Renderer/VulkanRenderer.cpp:6293, 7016	texture upload short-circuit + the draw-time content-sum memo
SamplerObject::GetVersion()	DirectGLES/Managers.cpp:4756, 8534; Managers.h:1016; Renderer/UniformManager.cpp:655; Renderer/VkSamplerManager.cpp:401	sampler twin re-sync
ITextureObject::GetShapeVersion()	Renderer/VkTextureManager.cpp:1647, 1756	image recreate decision
ITextureObject::GetTextureParamsVersion()	14 sites, e.g. DirectGLES/Managers.cpp:3647, 3777, 3847	texture-parameter re-push
ProgramObject::GetBackendStateVersion() / GetLinkVersion() / GetImageUnitVersion() / GetUBOContentVersion() / GetBlockBindingVersion()	DirectGLES/DirectGLES.cpp:3335, 3350, 3540, 2798, 2799, 3715, 3401; Renderer/UniformManager.cpp:2273; DirectVulkan/DirectVulkan.cpp:165	program twin re-sync + UBO re-upload
VertexArrayObject::GetConfigVersion()	DirectGLES/DirectGLES.cpp:1258, 2962; DirectGLES/Managers.cpp:2306	VAO re-emit
FramebufferObject::GetObjectVersion()	DirectGLES/DirectGLES.cpp:1615, 1918, 2937	FBO twin re-sync

2.5 BufferBackendOps — the reverse (frontend → backend) immediate-op table

Declared MobileGL/MG_State/GLState/BufferState/BufferObject.h:76-123; seven function pointers: Respecify, SubData, ResidentSubData, FlushMappedRange, OnDestroy, AcquirePersistentMap, ReadbackFromGpu. Every one takes BufferObject& — a frontend object by reference, and the callee reads the frontend shadow through it.

backend	table	registered	unregistered
DirectGLES	g_glesBufferBackendOps (DirectGLES/Managers.cpp:1351-1361, all seven filled, each wrapped in a …Tracked shim that bumps the buffer-mutation epoch)	Managers.cpp:1374-1379 RegisterBufferBackendOps(), called from DirectGLES/BackendObject_DirectGLES.cpp:849 and DirectGLES/DirectGLES.cpp:10063	Managers.cpp:1381-1392, also from OnBackendContextDestroyed (Managers.cpp:1397)
DirectVulkan	g_vulkanBufferBackendOps (Renderer/VkBufferManager.cpp:106-113, six filled — ResidentSubData is left null)	Renderer/VkBufferManager.cpp:132 inside VkBufferManager::Initialize	Renderer/VkBufferManager.cpp:139-141 inside Shutdown

The epoch the GLES shims maintain (Managers.cpp:1362-1372, CurrentBufferMutationEpoch / BumpBufferMutationEpoch) is itself a frontend-write-visibility signal the draw path memos read.

2.6 Backend → frontend writes (not pulls, but the same coupling, and P1 must not miss them)

These are calls the backend makes that mutate a frontend object. They are the mirror image of the pull sites and a pipe with only a pull direction will silently drop them:

method on frontend object	sites
BufferObject::MarkGpuWritten()	DirectGLES/DirectGLES.cpp:510, 1828; Renderer/UniformManager.cpp:1074, 1230
BufferObject::SetBackendResource()	DirectGLES/Managers.cpp:1015, 1482; Renderer/VkBufferManager.cpp:297 (+1)
BufferObject::EnsureGpuResidentStorage()	Renderer/UniformManager.cpp:1072, 1228; Renderer/VulkanRenderer.cpp:11326
BufferObject::WritebackFromBackend()	DirectGLES/Managers.cpp:1279
ITextureObject::AllocateStorage() / MarkStorageDirty() / TruncateMipmapLevels() / SetInternalFormat() / SetSamples() / SetFixedSampleLocations()	DirectGLES/DirectGLES.cpp:6326, 6327; Renderer/UniformManager.cpp:1484, 1489, 1490, 1496, 1497, 1498, 1625, 1628, 1635
ProgramObject::SetDrawID() / SetBaseVertex() / SetBaseInstance() / SetViewportPassMask()	DirectGLES/DirectGLES.cpp:3683, 3689, 3677, 3813
ProgramObject::AttachShader() / Link() / MarkUBOContentDirty() / SetBackendHashMemo()	Renderer/VulkanRenderer.cpp:4233, 4234, 4235, 4313, 4315, 4665, 8564; Renderer/ProgramFactory.cpp:3448
VertexArrayObject::SetBackendHashMemo() / SetBackendStateMemo() / SetBackendAuxMemo()	Renderer/VertexInputStateFactory.cpp:60, 78, 83
SamplerObject::SetWrapS/T/R, SetMinFilter, SetMagFilter, SetMipmapMode, SetLodRange	Renderer/VulkanRenderer.cpp:4270-4276
GLContext::RecordError()	6 sites, §3 accessor RecordError
GLContext::InvalidateCompileEnv()	2 sites, §3 accessor InvalidateCompileEnv

2.7 Frontend-object method surface reached through the pulled references

Counted by receiver-name heuristic over MG_Backend/** (excludes comment lines). This is the size of the "handle + value block" problem P1 inherits once the arrow sites are replaced:

frontend class	distinct methods called	call sites	top methods
BufferObject	16	169	GetSize 50, MappedData 42, SyncPersistentMappedRange 20, GetChangeSerial 15, GetBackendResource 11, SyncGpuWrites 6
ITextureObject	38	411	GetExternalIndex 147, GetTarget 48, GetFormat 47, GetTextureParamsVersion 14, GetStorageType 11, IsTextureView 11, GetLifetimeId 10
ProgramObject	56	275	GetExternalIndex 69, GetLifetimeId 14, GetLinkStatus 14, GetUBOSize 14, GetUniformLocation 12, GetUniformSamplerOrImageUnitIndex 10
FramebufferObject	9	115	GetAttachment 39, GetExternalIndex 19, IsDefaultFramebuffer 18, GetDrawBuffers 16, GetReadBuffer 8, GetObjectVersion 7
SamplerObject	26	52	GetVersion 5, GetAllSamplerParameters 3, then one-per-parameter getters (GetWrapS/T/R, GetMinFilter, …)
VertexArrayObject	12	40	GetIndexBufferBindingSlot 11, GetAttribute 6, GetConfigVersion 6, GetBackendHashMemo 4, GetLifetimeId 4

Total ≈ 1062 method calls on frontend objects across 157 distinct methods. MGPResourceDesc, MGPProgramDesc, MGPSamplerDesc, MGPFramebufferState and MGPVertexElements in MG_Pipe/PipeFields.def are the intended replacements; the field lists there are visibly narrower than this surface, which is the second thing P1 has to reconcile.

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3. (a) The PipeInputs accessor surface

Return types are from MobileGL/MG_State/GLState/Core.h (the GLContext class body starts at Core.h:61). "sites" is the count from §0.2; full site lists are in §1.

3.1 Accessors that return a handle to a frontend object (must become an MGPipeHandle)

accessor	signature (Core.h)	sites	verb paths served
GetBufferBindingSlot	BindingSlot<BufferObject>& GetBufferBindingSlot(BufferTarget) — Core.h:78	29	draw (indirect/parameter), dispatch (indirect), readback (PixelPack), buffer op (SyncBoundBuffer)
GetBufferBindingPoint	BindingSlotRange1D<BufferObject>& GetBufferBindingPoint(BufferTarget, Uint) — Core.h:79	9	buffer op (SSBO/UBO/atomic), xfb, program/uniform sync (descriptor)
GetFramebufferBindingSlot	BindingSlot<FramebufferObject>& GetFramebufferBindingSlot(FramebufferTarget) — Core.h:473	19 (+5 via the fast cache, §2.1)	framebuffer sync, clear, blit, readback, draw, pipeline build
GetTextureUnitObject	TextureUnit& GetTextureUnitObject(Int) — Core.h:120	19	texture op, program/uniform sync (descriptor)
GetImageTextureBinding	ImageTextureBinding& GetImageTextureBinding(Int) (+ const overload) — Core.h:121-122	7	texture op (image unit), program/uniform sync (storage image/texel)
GetBoundVertexArray	const SharedPtr<VertexArrayObject>& GetBoundVertexArray() — Core.h:102	12	vertex sync, draw
GetProgramForDraw	const SharedPtr<ProgramObject>& GetProgramForDraw() — Core.h:174	7	draw, program/uniform sync
GetProgramForDispatch	const SharedPtr<ProgramObject>& GetProgramForDispatch() — Core.h:179	3	dispatch
GetProgramObject	const SharedPtr<ProgramObject>& GetProgramObject(Uint) — Core.h:159	3	program/uniform sync (ShaderStorageBlockBinding, GetBackendProgramId)
GetTextureObject	const SharedPtr<ITextureObject>& GetTextureObject(Uint) — Core.h:110	1	texture op (VkTextureManager::SyncTextureAndGetDescriptor liveness check)
GetTransformFeedbackProgram	const SharedPtr<ProgramObject>& GetTransformFeedbackProgram() const — Core.h:329	3	xfb
GetCurrentVertexAttribute	const CurrentVertexAttributeValue& GetCurrentVertexAttribute(Uint) — Core.h:106	2	vertex sync

The four in bold below return a reference to a mutable slot, not a value, so a PipeInputs accessor cannot simply copy them: GetBufferBindingSlot, GetBufferBindingPoint, GetFramebufferBindingSlot, GetTextureUnitObject. Every call site immediately follows with .GetBoundObject(), .GetRange(), .GetVersion() or .GetSamplerObject(); those are the value blocks P1 must materialise. PipeFields.def already models them as MGPVertexBuffer, MGPIndexBuffer, MGPIndirectBuffers, MGPBufferRange, MGPShaderBuffers, MGPBoundView, MGPSamplerViews, MGPImageView, MGPFramebufferState.

3.2 Accessors that return a plain value (a PipeInputs field can hold them verbatim)

accessor	return type (Core.h line)	sites
GetActiveTextureUnit	Int (146)	8
GetBlendColor	const FloatVec4& (278)	1
GetBlendEquationIndexed	void(Uint, BlendEquation&, BlendEquation&) — out-params (255)	1
GetBlendFuncIndexed	void(Uint, BlendFactor&×4) — out-params (250)	1
GetBufferBindingPointCount	constexpr SizeT(BufferTarget) (80)	3
GetTouchedBufferBindingPointCount	SizeT(BufferTarget) (86)	2
GetClampReadColor	GLenum (235)	1
GetClearColor	const FloatVec4& (272)	1
GetClearDepth	Float (274)	1
GetClearStencil	Uint32 (276)	1
GetColorMaskIndexed	BoolVec4(Uint) (270)	6
GetCullFaceMode	CullFaceMode (294)	1
GetDepthFunc	DepthTestFunc (259)	1
GetDepthMask	Bool (261)	5
GetDepthRangeIndexed	const FloatVec2&(Uint) (282)	1
GetLineWidth	Float (211)	1
GetLogicOp	LogicOperation (257)	1
GetMaxTouchedTextureUnit	Int (126)	1
GetMinSampleShadingValue	Float (289)	1
GetPatchDefaultInnerLevel	const FloatVec2& (219)	3
GetPatchDefaultOuterLevel	const FloatVec4& (217)	3
GetPatchVertices	Uint (215)	3
GetPixelStoreParameters	PixelStoreParameters(Bool isUnpack) (292)	6 (all with isUnpack=false)
GetPolygonModeFront	GLenum (237)	1
GetPolygonOffsetFactor	Float (222)	1
GetPolygonOffsetUnits	Float (223)	1
GetPrimitiveRestartIndex	Uint32 (240)	3
GetProvokingVertexMode	ProvokingVertexMode (298)	1
GetRenderStateParameters	const RenderStateParameters& (205)	11
GetScissorBox	const IntVec4& (300)	3
GetStencilState	const StencilFaceState&(StencilFace) (266)	8
GetViewport	IntVec4 (207)	1
GetViewportIndexed	const FloatVec4&(Uint) (209)	1
IsCapabilityEnabled	Bool(CapabilityInput) (242)	29
IsCapabilityEnabledIndexed	Bool(CapabilityInput, Uint) (244)	1
IsTransformFeedbackActive	Bool (325)	5
IsTransformFeedbackPaused	Bool (326)	2
HasOpenTransformFeedbackSpan	Bool(Uint64 lifetimeId) (450) — NOT in PipeFilled.inc	1
ValidateProgramName	Bool(Uint) const (157) — pseudo-call kClientResolved	3

The 14 distinct CapabilityInput values the 30 capability reads ask for (P1's CapabilityBits block, which PipeFields.def already names in MGP_FIELDS_ResidualValueBlock): FramebufferSrgb, RasterizerDiscard, PrimitiveRestart, PrimitiveRestartFixedIndex, Multisample, SampleMask, CullFace, DepthTest, PolygonOffsetFill, ColorLogicOp, StencilTest, SampleShading, ScissorTest, Blend (only via IsCapabilityEnabledIndexed).

3.3 Accessors that return a version / generation counter (memo keys)

accessor	return type (Core.h line)	sites	memo it keys
GetPipelineStateVersion	Uint (204)	3	Vulkan pipeline cache + fast-path snapshot
GetRenderStateParametersVersion	Uint (202)	2	GLES render-state shadow, Vulkan dynamic-state tail
GetTextureBindGeneration	Uint64 (130)	5	per-draw sampled-texture set
GetSamplingResolutionGeneration	Uint64 (136)	9	mipmap-completeness re-resolve
GetTextureContextId	Uint64 (143)	6	disambiguates a recreated context at the same address
GetTransformFeedbackGeneration	Uint64 (334)	1	xfb counter-buffer rebind
GetTransformFeedbackCapturedVertices	Uint64 (357)	1	GLES scatter-capture record count
GetTransformFeedbackPausedPrimitiveCounter	Uint64 (349)	2	xfb primitives-written query
GetBoundTransformFeedbackLifetimeId	Uint64 (441) — NOT in PipeFilled.inc	1	Vulkan xfb counter-slot ownership

3.4 Non-read accessors (reverse channel / client-resolved)

accessor	signature	sites	Coverage.def classification
RecordError	void(ErrorCode, UniquePtr<ErrorInfo>) — Core.h:66	6	kReverseChannel
InvalidateCompileEnv	void() — Core.h:506	2	kClientResolved
ValidateProgramName	Bool(Uint) const — Core.h:157	3	kClientResolved

3.5 Reconciliation with PipeFilled.inc's 61 fields

fields in PipeFilled.inc (generated/PipeFilled.inc:28-90, asserted at :92)	61
distinct accessors read by the backends on this tree	61 (+.get())
in PipeFilled.inc but never read by a backend	1 — GetBoundTransformFeedbackName (PipeFilled.inc:32)
read by a backend but absent from PipeFilled.inc	2 — GetBoundTransformFeedbackLifetimeId, HasOpenTransformFeedbackSpan
corrected field count for P1	62

Additional structural gaps that PipeInputs-as-generated does not model, all of which have real sites:

1. .get() on the context itself (DirectGLES.cpp:147) has no accessor to map to; the whole GetFramebufferBindingSlotFast cache (DirectGLES.cpp:142-155, 5 call sites) must be deleted or rebuilt on handles.
2. Slot version reads (BindingSlot::GetVersion(), 5 sites, §2.4) ride on GetFramebufferBindingSlot/GetBoundVertexArray and are not separate fields today; MGP_FIELDS_MGPBindRenderState has a Version and MGP_FIELDS_MGPFramebufferState has a ContentHash, but no field carries a framebuffer binding-slot version.
3. GetBufferBindingSlot is polymorphic over BufferTarget — Coverage.def:37-42 already flags this ("its rows split across set_vertex_buffers, set_index_buffer, set_indirect_buffers and set_shader_buffers once the inventory carries the target argument (P1)"). The five targets actually asked for are DrawIndirect (13 sites), Parameter (4), PixelPack (7), DispatchIndirect (1), plus a runtime target parameter at DirectGLES.cpp:518 (SyncBoundBuffer, called with DrawIndirect @:664 and DispatchIndirect @:691).
4. GetBufferBindingPoint is likewise polymorphic: TransformFeedback (3), ShaderStorage (1), AtomicCounter (1), Uniform (2), plus a runtime target/bufferTarget at DirectGLES.cpp:370 and UniformManager.cpp:1194.