Call parameters dtor for non trivial types

include/silk/fibers/fiber.h

@@ -27,6 +27,12 @@ static constexpr uint64_t FIBER_PARAMETERS_SIZE = 64;
  */
 using FiberMain = int(void * parameters) noexcept;
 
+/**
+ * Destructor for the fiber's parameter buffer. Called after the entry point returns.
+ * Null for trivially destructible parameter types.
+ */
+using ParametersDtor = void(void * parameters) noexcept;
+
 /**
  * Cooperative fiber scheduler with per-CPU threads, async IO, and work-stealing.
  */
@@ -57,7 +63,8 @@ class FiberScheduler
     [[nodiscard]] static int run(int (*fiberMain)(T *) noexcept, T && parameters, FiberFuture * future) noexcept
     {
         static_assert(sizeof(T) <= FIBER_PARAMETERS_SIZE);
-        Fiber * fiber = allocateFiber(reinterpret_cast<FiberMain *>(fiberMain), future);
+        Fiber * fiber = allocateFiber(
+            reinterpret_cast<FiberMain *>(fiberMain), std::is_trivially_destructible_v<T> ? nullptr : destroyParameters<T>, future);
         if (fiber)
         {
             std::construct_at(static_cast<T *>(getFiberParameters(fiber)), std::forward<T>(parameters));
@@ -355,9 +362,15 @@ class FiberScheduler
     // Helpers.
     //
 
+    template <typename T>
+    static void destroyParameters(void * p) noexcept
+    {
+        std::destroy_at(static_cast<T *>(p));
+    }
+
     static void buildStealCandidates() noexcept;
     static void * getFiberParameters(Fiber * fiber) noexcept;
-    static Fiber * allocateFiber(FiberMain * fiberMain, FiberFuture * future) noexcept;
+    static Fiber * allocateFiber(FiberMain * fiberMain, ParametersDtor * parametersDtor, FiberFuture * future) noexcept;
     static void freeFiber(Fiber * fiber) noexcept;
     static void enqueueReady(Fiber * fiber) noexcept;
     static void yieldSuspendCallback(Fiber * fiber, void * context) noexcept;

src/fibers/fiber.cpp

@@ -117,7 +117,7 @@ class Fiber
     Fiber(bool isProxyFiber = false) noexcept;
     ~Fiber() noexcept;
 
-    bool initialize(FiberMain * fiberMain, FiberFuture * waitingFuture) noexcept;
+    bool initialize(FiberMain * fiberMain, ParametersDtor * parametersDtor, FiberFuture * waitingFuture) noexcept;
     void deinitialize() noexcept;
 
     void switchToFiberContext() noexcept;
@@ -193,8 +193,11 @@ class Fiber
     // dummy is stored here so it can be reused.
     QueueBase::QueueNode queueNode;
 
-    // Entry point and parameters buffer.
+    // Entry point, parameters buffer, and optional parameters destructor.
+    // parametersDtor is set by run<T> for non-trivially-destructible T and
+    // called by fiberContextMain immediately after fiberMain returns.
     FiberMain * fiberMain = nullptr;
+    ParametersDtor * parametersDtor = nullptr;
     uint8_t parameters[FIBER_PARAMETERS_SIZE];
 
 #if defined(__SANITIZE_ADDRESS__)
@@ -250,7 +253,7 @@ Fiber::~Fiber() noexcept
     }
 }
 
-bool Fiber::initialize(FiberMain * fiberMain_, FiberFuture * waitingFuture_) noexcept
+bool Fiber::initialize(FiberMain * fiberMain_, ParametersDtor * parametersDtor_, FiberFuture * waitingFuture_) noexcept
 {
     state.store(FiberState::SUSPENDED, std::memory_order_relaxed);
 
@@ -289,6 +292,7 @@ bool Fiber::initialize(FiberMain * fiberMain_, FiberFuture * waitingFuture_) noe
 #endif
 
     fiberMain = fiberMain_;
+    parametersDtor = parametersDtor_;
     fiberContext = boost::context::detail::make_fcontext(
         static_cast<uint8_t *>(stack) + PAGE_SIZE + FIBER_STACK_SIZE, FIBER_STACK_SIZE, fiberContextMain);
 
@@ -299,6 +303,11 @@ void Fiber::deinitialize() noexcept
 {
     ASSERT(!suspendedEntry.is_linked());
 
+    if (parametersDtor)
+    {
+        parametersDtor(parameters);
+    }
+
 #if defined(__SANITIZE_THREAD__)
     TSAN_FIBER_DESTROY(tsanFiber);
     tsanFiber = nullptr;
@@ -1034,12 +1043,12 @@ void * FiberScheduler::getFiberParameters(Fiber * fiber) noexcept
     return fiber->parameters;
 }
 
-Fiber * FiberScheduler::allocateFiber(FiberMain * fiberMain, FiberFuture * future) noexcept
+Fiber * FiberScheduler::allocateFiber(FiberMain * fiberMain, ParametersDtor * parametersDtor, FiberFuture * future) noexcept
 {
     Fiber * fiber = scheduler->fiberPool.allocate();
     if (fiber)
     {
-        if (fiber->initialize(fiberMain, future))
+        if (fiber->initialize(fiberMain, parametersDtor, future))
         {
             Perf::getSimpleCounter(simpleCounters[FIBER_STARTED]).increment();
             return fiber;