Removed custom fibers implementation due to issues caused on Windows

Looks like the Windows ATL doesn't play along well at all. What a bummer.

.gitmodules

@@ -55,9 +55,6 @@
 [submodule "externals/SPIRV-Headers"]
 	path = externals/SPIRV-Headers
 	url = https://github.com/KhronosGroup/SPIRV-Headers.git
-[submodule "externals/boost-headers"]
-	path = externals/boost-headers
-	url = https://github.com/boostorg/headers.git
 [submodule "externals/SPIRV-Tools"]
 	path = externals/SPIRV-Tools
 	url = https://github.com/KhronosGroup/SPIRV-Tools.git

CMakeLists.txt

@@ -275,8 +275,17 @@ endif()
 # Configure C++ standard
 # ===========================
 
-set(CMAKE_CXX_STANDARD 20)
-set(CMAKE_CXX_STANDARD_REQUIRED ON)
+# boost asio's concept usage doesn't play nicely with some compilers yet.
+add_definitions(-DBOOST_ASIO_DISABLE_CONCEPTS)
+if (MSVC)
+    add_compile_options($<$<COMPILE_LANGUAGE:CXX>:/std:c++20>)
+
+    # boost still makes use of deprecated result_of.
+    add_definitions(-D_HAS_DEPRECATED_RESULT_OF)
+else()
+    set(CMAKE_CXX_STANDARD 20)
+    set(CMAKE_CXX_STANDARD_REQUIRED ON)
+endif()
 
 # Output binaries to bin/
 set(CMAKE_RUNTIME_OUTPUT_DIRECTORY ${PROJECT_BINARY_DIR}/bin)
@@ -285,6 +294,7 @@ set(CMAKE_RUNTIME_OUTPUT_DIRECTORY ${PROJECT_BINARY_DIR}/bin)
 # =======================================================================
 
 # Enforce the search mode of non-required packages for better and shorter failure messages
+find_package(Boost 1.79.0 REQUIRED context)
 find_package(enet 1.3 MODULE)
 find_package(fmt 9 REQUIRED)
 find_package(LLVM 17.0.2 MODULE COMPONENTS Demangle)
@@ -674,6 +684,8 @@ function(create_target_directory_groups target_name)
     endforeach()
 endfunction()
 
+# Prevent boost from linking against libs when building
+target_link_libraries(Boost::headers INTERFACE Boost::disable_autolinking)
 # Adjustments for MSVC + Ninja
 if (MSVC AND CMAKE_GENERATOR STREQUAL "Ninja")
     add_compile_options(

README.md

@@ -72,7 +72,7 @@ Alternatively, you can clone from the [GitHub mirror repository](https://github.
 
 Note that above repository may be taken down any time. Do not rely on its existence in production. In case the GitHub mirror goes down, a mirror will be set up on Gitlab.
 
-This project incorporates several commits from the [Suyu](https://suyu.dev) and [Sudachi](https://github.com/sudachi-emu/sudachi) forks (but cleaned up due to the typically mediocre code/commit quality from both projects) as well as some custom changes, including lowered minimum boost library version requirements and faster fibers.
+This project incorporates several commits from the [Suyu](https://suyu.dev) and [Sudachi](https://github.com/sudachi-emu/sudachi) forks (but cleaned up due to the typically mediocre code/commit quality from both projects) as well as changes listed in **Changes**.
 
 ## Building
 

externals/CMakeLists.txt

@@ -172,9 +172,6 @@ if (YUZU_USE_EXTERNAL_VULKAN_SPIRV_TOOLS)
     add_subdirectory(SPIRV-Tools)
 endif()
 
-# Boost headers
-add_subdirectory(boost-headers)
-
 # TZDB (Time Zone Database)
 add_subdirectory(nx_tzdb)
 

src/common/CMakeLists.txt

@@ -259,7 +259,7 @@ if (CMAKE_CXX_COMPILER_ID STREQUAL "Clang")
   )
 endif()
 
-target_link_libraries(common PUBLIC Boost::headers fmt::fmt microprofile stb::headers Threads::Threads)
+target_link_libraries(common PUBLIC Boost::context Boost::headers fmt::fmt microprofile stb::headers Threads::Threads)
 target_link_libraries(common PRIVATE lz4::lz4 zstd::zstd LLVM::Demangle)
 
 if (ANDROID)

src/common/fiber.cpp

@@ -5,46 +5,87 @@
 
 #include "common/assert.h"
 #include "common/fiber.h"
-#define MINICORO_IMPL
-#include "common/minicoro.h"
+#include "common/virtual_buffer.h"
+
+#include <boost/context/detail/fcontext.hpp>
 
 namespace Common {
 
+constexpr std::size_t default_stack_size = 512 * 1024;
+
 struct Fiber::FiberImpl {
-    FiberImpl() {}
+    FiberImpl() : stack{default_stack_size}, rewind_stack{default_stack_size} {}
+
+    VirtualBuffer<u8> stack;
+    VirtualBuffer<u8> rewind_stack;
 
     std::mutex guard;
-    bool released{};
-    bool is_thread_fiber{};
-    Fiber* next_fiber{};
-    Fiber** next_fiber_ptr;
     std::function<void()> entry_point;
+    std::function<void()> rewind_point;
+    std::shared_ptr<Fiber> previous_fiber;
+    bool is_thread_fiber{};
+    bool released{};
 
-    mco_coro* context;
+    u8* stack_limit{};
+    u8* rewind_stack_limit{};
+    boost::context::detail::fcontext_t context{};
+    boost::context::detail::fcontext_t rewind_context{};
 };
 
-Fiber::Fiber() : impl{std::make_unique<FiberImpl>()} {
-    impl->is_thread_fiber = true;
+void Fiber::SetRewindPoint(std::function<void()>&& rewind_func) {
+    impl->rewind_point = std::move(rewind_func);
+}
+
+void Fiber::Start(boost::context::detail::transfer_t& transfer) {
+    ASSERT(impl->previous_fiber != nullptr);
+    impl->previous_fiber->impl->context = transfer.fctx;
+    impl->previous_fiber->impl->guard.unlock();
+    impl->previous_fiber.reset();
+    impl->entry_point();
+    UNREACHABLE();
+}
+
+void Fiber::OnRewind([[maybe_unused]] boost::context::detail::transfer_t& transfer) {
+    ASSERT(impl->context != nullptr);
+    impl->context = impl->rewind_context;
+    impl->rewind_context = nullptr;
+    u8* tmp = impl->stack_limit;
+    impl->stack_limit = impl->rewind_stack_limit;
+    impl->rewind_stack_limit = tmp;
+    impl->rewind_point();
+    UNREACHABLE();
+}
+
+void Fiber::FiberStartFunc(boost::context::detail::transfer_t transfer) {
+    auto* fiber = static_cast<Fiber*>(transfer.data);
+    fiber->Start(transfer);
+}
+
+void Fiber::RewindStartFunc(boost::context::detail::transfer_t transfer) {
+    auto* fiber = static_cast<Fiber*>(transfer.data);
+    fiber->OnRewind(transfer);
 }
 
 Fiber::Fiber(std::function<void()>&& entry_point_func) : impl{std::make_unique<FiberImpl>()} {
     impl->entry_point = std::move(entry_point_func);
-    auto desc = mco_desc_init(
-        [](mco_coro* coro) { reinterpret_cast<Fiber*>(coro->user_data)->impl->entry_point(); }, 0);
-    desc.user_data = this;
-    mco_result res = mco_create(&impl->context, &desc);
-    ASSERT(res == MCO_SUCCESS);
+    impl->stack_limit = impl->stack.data();
+    impl->rewind_stack_limit = impl->rewind_stack.data();
+    u8* stack_base = impl->stack_limit + default_stack_size;
+    impl->context =
+        boost::context::detail::make_fcontext(stack_base, impl->stack.size(), FiberStartFunc);
 }
 
+Fiber::Fiber() : impl{std::make_unique<FiberImpl>()} {}
+
 Fiber::~Fiber() {
     if (impl->released) {
         return;
     }
-    DestroyPre();
-    if (impl->is_thread_fiber) {
-        DestroyThreadFiber();
-    } else {
-        DestroyWorkFiber();
+    // Make sure the Fiber is not being used
+    const bool locked = impl->guard.try_lock();
+    ASSERT_MSG(locked, "Destroying a fiber that's still running");
+    if (locked) {
+        impl->guard.unlock();
     }
 }
 
@@ -53,66 +94,42 @@ void Fiber::Exit() {
     if (!impl->is_thread_fiber) {
         return;
     }
-    DestroyPre();
-    DestroyThreadFiber();
-}
-
-void Fiber::DestroyPre() {
-    // Make sure the Fiber is not being used
-    const bool locked = impl->guard.try_lock();
-    ASSERT_MSG(locked, "Destroying a fiber that's still running");
-    if (locked) {
-        impl->guard.unlock();
-    }
+    impl->guard.unlock();
     impl->released = true;
 }
 
-void Fiber::DestroyWorkFiber() {
-    mco_result res = mco_destroy(impl->context);
-    ASSERT(res == MCO_SUCCESS);
-}
-
-void Fiber::DestroyThreadFiber() {
-    if (impl->next_fiber_ptr && *impl->next_fiber_ptr) {
-        *impl->next_fiber_ptr = nullptr;
-    }
+void Fiber::Rewind() {
+    ASSERT(impl->rewind_point);
+    ASSERT(impl->rewind_context == nullptr);
+    u8* stack_base = impl->rewind_stack_limit + default_stack_size;
+    impl->rewind_context =
+        boost::context::detail::make_fcontext(stack_base, impl->stack.size(), RewindStartFunc);
+    boost::context::detail::jump_fcontext(impl->rewind_context, this);
 }
 
 void Fiber::YieldTo(std::weak_ptr<Fiber> weak_from, Fiber& to) {
+    to.impl->guard.lock();
+    to.impl->previous_fiber = weak_from.lock();
+
+    auto transfer = boost::context::detail::jump_fcontext(to.impl->context, &to);
+
+    // "from" might no longer be valid if the thread was killed
     if (auto from = weak_from.lock()) {
-        if (!from->impl->is_thread_fiber) {
-            // Set next fiber
-            from->impl->next_fiber = &to;
-            // Yield from thread
-            if (!from->impl->released) {
-                from->impl->guard.unlock();
-                mco_yield(from->impl->context);
-            }
-        } else {
-            from->impl->guard.lock();
-            // Keep running next fiber until they've ran out
-            auto& next_fiber_ptr = from->impl->next_fiber_ptr;
-            next_fiber_ptr = &from->impl->next_fiber;
-            *next_fiber_ptr = &to;
-            while (*next_fiber_ptr) {
-                auto next = *next_fiber_ptr;
-                *next_fiber_ptr = nullptr;
-                next_fiber_ptr = &next->impl->next_fiber;
-                // Stop if new thread is thread fiber
-                if (next->impl->is_thread_fiber)
-                    break;
-                // Resume new thread
-                next->impl->guard.lock();
-                mco_result res = mco_resume(next->impl->context);
-                ASSERT(res == MCO_SUCCESS);
-            }
-            from->impl->guard.unlock();
+        if (from->impl->previous_fiber == nullptr) {
+            ASSERT_MSG(false, "previous_fiber is nullptr!");
+            return;
         }
+        from->impl->previous_fiber->impl->context = transfer.fctx;
+        from->impl->previous_fiber->impl->guard.unlock();
+        from->impl->previous_fiber.reset();
     }
 }
 
 std::shared_ptr<Fiber> Fiber::ThreadToFiber() {
-    return std::shared_ptr<Fiber>{new Fiber()};
+    std::shared_ptr<Fiber> fiber = std::shared_ptr<Fiber>{new Fiber()};
+    fiber->impl->guard.lock();
+    fiber->impl->is_thread_fiber = true;
+    return fiber;
 }
 
 } // namespace Common

src/common/fiber.h

@@ -6,7 +6,9 @@
 #include <functional>
 #include <memory>
 
-#include "common/minicoro.h"
+namespace boost::context::detail {
+struct transfer_t;
+}
 
 namespace Common {
 
@@ -36,18 +38,25 @@ public:
     Fiber(Fiber&&) = default;
     Fiber& operator=(Fiber&&) = default;
 
+    /// Yields control from Fiber 'from' to Fiber 'to'
+    /// Fiber 'from' must be the currently running fiber.
     static void YieldTo(std::weak_ptr<Fiber> weak_from, Fiber& to);
     [[nodiscard]] static std::shared_ptr<Fiber> ThreadToFiber();
 
+    void SetRewindPoint(std::function<void()>&& rewind_func);
+
+    void Rewind();
+
     /// Only call from main thread's fiber
     void Exit();
 
 private:
     Fiber();
 
-    void DestroyPre();
-    void DestroyWorkFiber();
-    void DestroyThreadFiber();
+    void OnRewind(boost::context::detail::transfer_t& transfer);
+    void Start(boost::context::detail::transfer_t& transfer);
+    static void FiberStartFunc(boost::context::detail::transfer_t transfer);
+    static void RewindStartFunc(boost::context::detail::transfer_t transfer);
 
     struct FiberImpl;
     std::unique_ptr<FiberImpl> impl;

src/tests/common/fibers.cpp

@@ -271,4 +271,43 @@ TEST_CASE("Fibers::StartRace", "[common]") {
     REQUIRE(test_control.value3 == 1);
 }
 
+class TestControl4;
+
+class TestControl4 {
+public:
+    TestControl4() {
+        fiber1 = std::make_shared<Fiber>([this] { DoWork(); });
+        goal_reached = false;
+        rewinded = false;
+    }
+
+    void Execute() {
+        thread_fiber = Fiber::ThreadToFiber();
+        Fiber::YieldTo(thread_fiber, *fiber1);
+        thread_fiber->Exit();
+    }
+
+    void DoWork() {
+        fiber1->SetRewindPoint([this] { DoWork(); });
+        if (rewinded) {
+            goal_reached = true;
+            Fiber::YieldTo(fiber1, *thread_fiber);
+        }
+        rewinded = true;
+        fiber1->Rewind();
+    }
+
+    std::shared_ptr<Common::Fiber> fiber1;
+    std::shared_ptr<Common::Fiber> thread_fiber;
+    bool goal_reached;
+    bool rewinded;
+};
+
+TEST_CASE("Fibers::Rewind", "[common]") {
+    TestControl4 test_control{};
+    test_control.Execute();
+    REQUIRE(test_control.goal_reached);
+    REQUIRE(test_control.rewinded);
+}
+
 } // namespace Common