[Test] (P13 W3b): restore the borrowed-slot unit-memo probe, pinned to the mask whose sync body it observes

MobileGL/MG_Test/SanityTest.cpp

@@ -3040,6 +3040,156 @@ TEST(UnorderedMapSanity, ErasingTheOnlyElementReturnsEnd) {
     EXPECT_TRUE(map.empty());
 }
 
+namespace {
+    // Records what the per-unit texture sync actually pushed at the driver: which backend
+    // texture id was current when each glTexImage2D landed, and the shape it was given.
+    struct TexSpecCall {
+        GLuint texture;
+        GLsizei width;
+        GLsizei height;
+    };
+    MobileGL::Vector<TexSpecCall>* g_texSpecCalls = nullptr;
+    GLuint g_texSpecBoundTexture = 0;
+
+    void TS_BindTexture(GLenum, GLuint texture) { g_texSpecBoundTexture = texture; }
+    void TS_ActiveTexture(GLenum) {}
+    void TS_TexParameteri(GLenum, GLenum, GLint) {}
+    void TS_TexParameterf(GLenum, GLenum, GLfloat) {}
+    void TS_TexParameterfv(GLenum, GLenum, const GLfloat*) {}
+    void TS_PixelStorei(GLenum, GLint) {}
+    void TS_BindBuffer(GLenum, GLuint) {}
+    void TS_TexImage2D(GLenum, GLint level, GLint, GLsizei width, GLsizei height, GLint, GLenum, GLenum,
+                       const void*) {
+        if (g_texSpecCalls && level == 0) {
+            g_texSpecCalls->push_back({g_texSpecBoundTexture, width, height});
+        }
+    }
+
+    // Clears the recording hook even when a gtest assertion unwinds the test body.
+    struct ScopedTexSpecRecording {
+        explicit ScopedTexSpecRecording(MobileGL::Vector<TexSpecCall>& sink) {
+            g_texSpecCalls = &sink;
+            g_texSpecBoundTexture = 0;
+        }
+        ~ScopedTexSpecRecording() { g_texSpecCalls = nullptr; }
+        ScopedTexSpecRecording(const ScopedTexSpecRecording&) = delete;
+        ScopedTexSpecRecording& operator=(const ScopedTexSpecRecording&) = delete;
+    };
+
+    // Gives `name` a complete single-level 2D image of the requested size without going through
+    // the frontend upload path (the mock table below wires only the state-pushing entry points).
+    MobileGL::SharedPtr<MobileGL::MG_State::GLState::ITextureObject> MakeComplete2DTexture(GLuint name,
+                                                                                           MobileGL::Int size) {
+        using namespace MobileGL;
+        MG_Impl::GLImpl::BindTexture(GL_TEXTURE_2D, name);
+        auto object = MG_State::pGLContext->GetTextureUnitObject(0)
+                          .GetBindingSlot(TextureTarget::Texture2D)
+                          .GetBoundObject();
+        object->SetInternalFormat(TextureInternalFormat::RGBA8);
+        MG_State::GLState::AsMipmapTexture(object.get())
+            ->AllocateStorage(TextureUploadTarget::Texture2D, 0, {{size, size, 1}, 4});
+        return object;
+    }
+} // namespace
+
+// The per-unit texture sync memo BORROWS the binding slot: an entry holds a pointer to the
+// slot's shared_ptr plus the backend twin of whatever was in it when the entry was built. Its
+// keys (context id, bind-generation epoch, high-water mark, sampling generation) are the primary
+// guard, but they are all derived state - so the memo also has to survive a slot swap that never
+// reached them.
+//
+// It did not. The DSA by-name emulation swapped a slot silently, every key still matched, and
+// the replay drove texture A's backend twin from texture B's frontend object: A's backend
+// storage was re-specified with B's shape, destroying anything A only ever had on the GPU. On
+// Espryt + Iris/BSL that blanked Minecraft's 16x16 lightmap the moment a 2048x2048 shadow map
+// was uploaded through a by-name call, and since the text shader multiplies by the lightmap,
+// `if (color.a < 0.1) discard` then threw away every glyph in the process - HUD, menus and the
+// vanilla title screen alike.
+TEST(DirectGLESTextureSync, UnitMemoRefusesToDriveATwinFromAnotherTexture) {
+    using namespace MobileGL;
+    // P13 W3b: PINNED TO THE P2 MASK, in its own process (ctest runs every case in one). The code
+    // under test - the monolith arm's borrowed-slot unit list and PairingsIntact - does not depend
+    // on the mask and is live at the shipping mask (UnitTexturesByHandle() is false on monolith).
+    // The mask only picks the twin-sync body this probe OBSERVES: at 0x3fff that body reads
+    // applier records, and a unit-lane process cannot create them (MGPipeApplyResourceCreate
+    // declines under NoP4aConsumer), so there the probe would see nothing. The hazard itself is
+    // not reachable through public GL any more (the by-name emulation bumps the bind generation
+    // and restores the slot before any draw - measured: DsaUpdateKeepsTheBoundUnitScenario stays
+    // green with both defences removed), so this state-level construction is its only red.
+    const Uint64 savedMask = MG_Config::Features.PipePush;
+    MG_Config::Features.PipePush = MG_Pipe::kMGPipeSubsystemsMigratedAtP2;
+    ASSERT_FALSE(MG_Backend::DirectGLES::TextureResourceSubsystemEnabled())
+        << "the texture-resource family arm latched before this case pinned its mask; run the case "
+           "in its own process, as ctest does";
+    ScopedDirectGLESTextureBindings scoped; // fresh GLContext + registry + binding caches
+    Vector<TexSpecCall> specs;
+    ScopedTexSpecRecording recording(specs);
+
+    auto functions = MG_Backend::DirectGLES::g_GLESFuncs;
+    functions.glBindTexture = TS_BindTexture;
+    functions.glActiveTexture = TS_ActiveTexture;
+    functions.glTexImage2D = TS_TexImage2D;
+    functions.glTexParameteri = TS_TexParameteri;
+    functions.glTexParameterf = TS_TexParameterf;
+    functions.glTexParameterfv = TS_TexParameterfv;
+    functions.glPixelStorei = TS_PixelStorei;
+    functions.glBindBuffer = TS_BindBuffer;
+    MG_Backend::DirectGLES::SetGLESFuncsTable(functions);
+
+    GLuint names[2] = {};
+    MG_Impl::GLImpl::GenTextures(2, names);
+    // `foreign` stands in for the shadow map, `resident` for the lightmap. Both are fully
+    // specified BEFORE the first sync so that nothing between the two syncs can move the
+    // sampling-resolution generation and invalidate the memo for an unrelated reason.
+    const auto foreign = MakeComplete2DTexture(names[1], 32);
+    const auto resident = MakeComplete2DTexture(names[0], 16);
+    ASSERT_NE(foreign, nullptr);
+    ASSERT_NE(resident, nullptr);
+
+    // First sync: builds the memo with unit 0 -> `resident`, and gives `resident`'s twin its
+    // 16x16 backend storage. The unit walk is the per-draw one, so both syncs below stand in a
+    // draw - the fill is what a real glDraw* would have done before reaching this helper.
+    MG_Test::ScopedPipeVerb draw(MG_Pipe::MGPipeVerb::DrawArrays);
+    MG_Backend::DirectGLES::TextureImpl::SyncNeccessaryTextures();
+    auto* residentSlot = MG_Backend::DirectGLES::TextureImpl::g_backendTextureObjects.Find(resident.get());
+    ASSERT_NE(residentSlot, nullptr);
+    ASSERT_NE(*residentSlot, nullptr);
+    const GLuint residentBackendId = (*residentSlot)->GetBackendTextureId();
+    ASSERT_NE(residentBackendId, 0u);
+    ASSERT_FALSE(specs.empty());
+    EXPECT_EQ(specs.back().texture, residentBackendId);
+    EXPECT_EQ(specs.back().width, 16);
+
+    // The hazard, reproduced at the state level: put `foreign` on the slot the memo borrows
+    // WITHOUT telling the binding accounting, exactly as the by-name emulation used to.
+    MG_State::pGLContext->GetTextureUnitObject(0).GetBindingSlot(TextureTarget::Texture2D).Bind(foreign);
+
+    const SizeT specsBeforeReplay = specs.size();
+    // The second draw. Its fill re-reads the memo's keys off the live context, which is the
+    // premise being tested: the silent slot swap moved none of them.
+    draw.Renew();
+    MG_Backend::DirectGLES::TextureImpl::SyncNeccessaryTextures();
+
+    // Above all, nothing may have re-specified the RESIDENT texture's backend storage. That single
+    // call is what destroyed the lightmap. (Checked FIRST since P13 W3b, so a red names the damage
+    // rather than stopping at the twin assertions below.)
+    for (SizeT i = specsBeforeReplay; i < specs.size(); ++i) {
+        EXPECT_NE(specs[i].texture, residentBackendId)
+            << "the stale memo entry re-specified the resident texture's backend storage with "
+            << specs[i].width << "x" << specs[i].height;
+    }
+
+    // ...and `foreign` must have been synced through its OWN twin.
+    auto* foreignSlot = MG_Backend::DirectGLES::TextureImpl::g_backendTextureObjects.Find(foreign.get());
+    ASSERT_NE(foreignSlot, nullptr) << "the replay never reached the texture now in the slot";
+    ASSERT_NE(*foreignSlot, nullptr);
+    const GLuint foreignBackendId = (*foreignSlot)->GetBackendTextureId();
+    EXPECT_NE(foreignBackendId, residentBackendId);
+
+    MG_Impl::GLImpl::BindTexture(GL_TEXTURE_2D, 0);
+    MG_Config::Features.PipePush = savedMask;
+}
+
 // P5e (tx2), CONTRACT-P5E §4.3: THE HANDLE ARM'S SIBLING OF UnitMemoRefusesToDriveATwinFromAnotherTexture,
 // WITH ABA AS THE HAZARD INSTEAD OF A SILENT SLOT SWAP. (P13 W3b retired that case: it ran only at
 // the P2 mask, whose legacy unit arm is gone now that subsystem bits 0-13 are fixed on.)