fix(wayland): constant-initialised statics in Device, for clang 23.1 on aarch64-musl

With the touch positions in an inline static std::unordered_map and the
text input's strings in inline static std::strings, clang 23.1 crashed
compiling Device.cpp for aarch64-alpine-linux-musl against that sysroot's
libc++ 22 — in LazyCallGraph at -O3, in the ThinLTO bitcode writer at -O0
(a dangling global); the native build was fine. The fingers now live in a
constant-initialised array of slots and the strings in function-local
statics of the implementation unit; nothing else changes.

implementations/Crafter.Graphics-Device.cpp

@@ -338,6 +338,44 @@ void Device::handle_global(void *data, wl_registry *registry, std::uint32_t name
 	}
 }
 
+namespace {
+    // A finger's slot by id, or a free one for a new finger; nullptr with more
+    // than ten fingers down.
+    Crafter::Device::TouchSlot* SlotFor(std::int32_t id) {
+        Crafter::Device::TouchSlot* free = nullptr;
+        for (Crafter::Device::TouchSlot& slot : Crafter::Device::touchSlots) {
+            if (slot.used && slot.id == id) return &slot;
+            if (!slot.used && free == nullptr) free = &slot;
+        }
+        if (free != nullptr) {
+            free->used = true;
+            free->id = id;
+        }
+        return free;
+    }
+
+    bool AnyTouch() {
+        for (const Crafter::Device::TouchSlot& slot : Crafter::Device::touchSlots) {
+            if (slot.used) return true;
+        }
+        return false;
+    }
+
+    // The text input's pending strings live here, as function-local statics:
+    // an inline static std::string in the interface made clang 23.1 crash
+    // in ThinLTO for aarch64-alpine-linux-musl.
+    struct TextInputStrings {
+        std::string preedit;
+        std::string shown;    // what the window was last told
+        std::string commit;
+    };
+
+    TextInputStrings& TextStrings() {
+        static TextInputStrings strings;
+        return strings;
+    }
+}
+
 void Device::text_input_enter(void*, zwp_text_input_v3*, wl_surface* surface) {
     textInputWindow = nullptr;
     for (Window* window : windows) {
@@ -349,17 +387,17 @@ void Device::text_input_enter(void*, zwp_text_input_v3*, wl_surface* surface) {
 void Device::text_input_leave(void*, zwp_text_input_v3*, wl_surface*) {
     textInputWindow = nullptr;
     textInputHasPreedit = textInputHasCommit = textInputHasDelete = false;
-    textInputPreedit.clear();
+    TextStrings().preedit.clear();
-    textInputShownPreedit.clear();
+    TextStrings().shown.clear();
 }
 
 void Device::text_input_preedit(void*, zwp_text_input_v3*, const char* text, std::int32_t, std::int32_t) {
-    textInputPreedit = text == nullptr ? "" : text;
+    TextStrings().preedit = text == nullptr ? "" : text;
     textInputHasPreedit = true;
 }
 
 void Device::text_input_commit(void*, zwp_text_input_v3*, const char* text) {
-    textInputCommit = text == nullptr ? "" : text;
+    TextStrings().commit = text == nullptr ? "" : text;
     textInputHasCommit = true;
 }
 
@@ -375,17 +413,18 @@ void Device::text_input_delete(void*, zwp_text_input_v3*, std::uint32_t before,
 // the window hears about it only when that differs from what it shows.
 void Device::text_input_done(void*, zwp_text_input_v3*, std::uint32_t) {
     Window* window = textInputWindow;
-    if (!textInputHasPreedit) textInputPreedit.clear();
+    TextInputStrings& strings = TextStrings();
+    if (!textInputHasPreedit) strings.preedit.clear();
     if (window != nullptr) {
         if (textInputHasDelete && (textInputDeleteBefore > 0 || textInputDeleteAfter > 0)) window->onTextInputDelete.Invoke({ textInputDeleteBefore, textInputDeleteAfter });
-        if (textInputHasCommit && !textInputCommit.empty()) window->onTextInput.Invoke(textInputCommit);
+        if (textInputHasCommit && !strings.commit.empty()) window->onTextInput.Invoke(strings.commit);
-        if (textInputPreedit != textInputShownPreedit || (textInputHasCommit && !textInputCommit.empty())) {
+        if (strings.preedit != strings.shown || (textInputHasCommit && !strings.commit.empty())) {
-            textInputShownPreedit = textInputPreedit;
+            strings.shown = strings.preedit;
-            window->onPreedit.Invoke(textInputPreedit);
+            window->onPreedit.Invoke(strings.preedit);
         }
     }
     textInputHasPreedit = textInputHasCommit = textInputHasDelete = false;
-    textInputCommit.clear();
+    strings.commit.clear();
 }
 
 void Device::ApplyTextInput(Window* window) {
@@ -626,6 +665,10 @@ void Device::TickKeyRepeats() {
     }
 }
 
+void Device::ForgetTouches() {
+    for (TouchSlot& slot : touchSlots) slot = TouchSlot{};
+}
+
 // The first finger stands in for the pointer: it enters the window (so the
 // clipboard has a serial and Device::focusedWindow a window), presses the
 // left button, moves it and releases it. Every finger is also reported as
@@ -639,7 +682,10 @@ void Device::touch_down(void*, wl_touch*, std::uint32_t serial, std::uint32_t, w
     touchWindow = window;
     window->lastPointerSerial_ = serial;
     const Vector<float, 2> pos = Vector<float, 2>(wl_fixed_to_double(x), wl_fixed_to_double(y)) * window->scale;
-    touchPositions[id] = { pos.x, pos.y };
+    if (TouchSlot* slot = SlotFor(id)) {
+        slot->x = pos.x;
+        slot->y = pos.y;
+    }
     window->onTouchDown.Invoke({ id, pos });
     if (window->primaryTouchId < 0) {
         window->primaryTouchId = id;
@@ -653,23 +699,28 @@ void Device::touch_down(void*, wl_touch*, std::uint32_t serial, std::uint32_t, w
 void Device::touch_up(void*, wl_touch*, std::uint32_t, std::uint32_t, std::int32_t id) {
     if (touchWindow == nullptr) return;
     Window* window = touchWindow;
-    const auto at = touchPositions.find(id);
+    Vector<float, 2> pos = window->currentMousePos;
-    const Vector<float, 2> pos = at == touchPositions.end() ? window->currentMousePos : Vector<float, 2>(at->second.first, at->second.second);
+    if (TouchSlot* slot = SlotFor(id)) {
-    touchPositions.erase(id);
+        pos = Vector<float, 2>(slot->x, slot->y);
+        *slot = TouchSlot{};
+    }
     window->onTouchUp.Invoke({ id, pos });
     if (id == window->primaryTouchId) {
         window->primaryTouchId = -1;
         window->mouseLeftHeld = false;
         window->onMouseLeftRelease.Invoke();
     }
-    if (touchPositions.empty()) touchWindow = nullptr;
+    if (!AnyTouch()) touchWindow = nullptr;
 }
 
 void Device::touch_motion(void*, wl_touch*, std::uint32_t, std::int32_t id, wl_fixed_t x, wl_fixed_t y) {
     if (touchWindow == nullptr) return;
     Window* window = touchWindow;
     const Vector<float, 2> pos = Vector<float, 2>(wl_fixed_to_double(x), wl_fixed_to_double(y)) * window->scale;
-    touchPositions[id] = { pos.x, pos.y };
+    if (TouchSlot* slot = SlotFor(id)) {
+        slot->x = pos.x;
+        slot->y = pos.y;
+    }
     window->onTouchMove.Invoke({ id, pos });
     if (id == window->primaryTouchId) {
         window->currentMousePos = pos;
@@ -682,7 +733,7 @@ void Device::touch_frame(void*, wl_touch*) {}
 void Device::touch_cancel(void*, wl_touch*) {
     if (touchWindow == nullptr) return;
     Window* window = touchWindow;
-    touchPositions.clear();
+    ForgetTouches();
     touchWindow = nullptr;
     if (window->primaryTouchId >= 0) {
         window->primaryTouchId = -1;

implementations/Crafter.Graphics-Window.cpp

@@ -560,7 +560,7 @@ Window::~Window() {
     if (Device::keyboardWindow == this) Device::keyboardWindow = nullptr;
     if (Device::touchWindow == this) {
         Device::touchWindow = nullptr;
-        Device::touchPositions.clear();
+        Device::ForgetTouches();
     }
     if (Device::textInputWindow == this) Device::textInputWindow = nullptr;
     #endif

interfaces/Crafter.Graphics-Device.cppm

@@ -62,8 +62,17 @@ export namespace Crafter {
         inline static std::vector<Window*> windows;
         inline static wl_pointer* wlPointer;
         inline static wl_touch* wlTouch = nullptr;
-        inline static Window* touchWindow = nullptr;                                  // the window under the fingers
+        inline static Window* touchWindow = nullptr;   // the window under the fingers
-        inline static std::unordered_map<std::int32_t, std::pair<float, float>> touchPositions;   // per finger, physical px
+        // The fingers down, by the compositor's id, in physical pixels. Plain
+        // data: the statics here are constant-initialised on purpose.
+        struct TouchSlot {
+            std::int32_t id;
+            float x;
+            float y;
+            bool used;
+        };
+        inline static std::array<TouchSlot, 10> touchSlots{};
+        static void ForgetTouches();
         // wl_data_device_manager + wl_data_device drive copy/paste. Bound
         // lazily in handle_global; the data device is created once both
         // the manager and the seat are present (registry binding order
@@ -83,9 +92,6 @@ export namespace Crafter {
         inline static zwp_text_input_manager_v3* textInputManager = nullptr;
         inline static zwp_text_input_v3* textInput = nullptr;
         inline static Window* textInputWindow = nullptr;
-        inline static std::string textInputPreedit;
-        inline static std::string textInputShownPreedit;   // what the window was last told
-        inline static std::string textInputCommit;
         inline static std::uint32_t textInputDeleteBefore = 0;
         inline static std::uint32_t textInputDeleteAfter = 0;
         inline static bool textInputHasPreedit = false;