core/debugger: Improved stepping mechanism and misc fixes

5 files changed, 134 insertions, 42 deletions

diff --git a/src/core/debugger/debugger.cpp b/src/core/debugger/debugger.cpp
index 7a2012d3c..a73f2279d 100644
--- a/src/core/debugger/debugger.cpp
+++ b/src/core/debugger/debugger.cpp
@@ -1,6 +1,7 @@
 // SPDX-FileCopyrightText: Copyright 2022 yuzu Emulator Project
 // SPDX-License-Identifier: GPL-2.0-or-later
 
+#include <algorithm>
 #include <mutex>
 #include <thread>
 
@@ -84,31 +85,31 @@ public:
         return active_thread;
     }
 
-    bool IsStepping() const {
-        return stepping;
-    }
-
 private:
     void InitializeServer(u16 port) {
         using boost::asio::ip::tcp;
 
         LOG_INFO(Debug_GDBStub, "Starting server on port {}...", port);
 
-        // Initialize the listening socket and accept a new client.
-        tcp::endpoint endpoint{boost::asio::ip::address_v4::loopback(), port};
-        tcp::acceptor acceptor{io_context, endpoint};
-        client_socket = acceptor.accept();
-
         // Run the connection thread.
-        connection_thread = std::jthread([&](std::stop_token stop_token) {
+        connection_thread = std::jthread([&, port](std::stop_token stop_token) {
             try {
+                // Initialize the listening socket and accept a new client.
+                tcp::endpoint endpoint{boost::asio::ip::address_v4::loopback(), port};
+                tcp::acceptor acceptor{io_context, endpoint};
+
+                acceptor.async_accept(client_socket, [](const auto&) {});
+                io_context.run_one();
+                io_context.restart();
+
+                if (stop_token.stop_requested()) {
+                    return;
+                }
+
                 ThreadLoop(stop_token);
             } catch (const std::exception& ex) {
                 LOG_CRITICAL(Debug_GDBStub, "Stopping server: {}", ex.what());
             }
-
-            client_socket.shutdown(client_socket.shutdown_both);
-            client_socket.close();
         });
     }
 
@@ -129,8 +130,7 @@ private:
         AllCoreStop();
 
         // Set the active thread.
-        active_thread = ThreadList()[0];
-        active_thread->Resume(Kernel::SuspendType::Debug);
+        UpdateActiveThread();
 
         // Set up the frontend.
         frontend->Connected();
@@ -142,7 +142,7 @@ private:
 
     void PipeData(std::span<const u8> data) {
         AllCoreStop();
-        active_thread->Resume(Kernel::SuspendType::Debug);
+        UpdateActiveThread();
         frontend->Stopped(active_thread);
     }
 
@@ -156,18 +156,22 @@ private:
                     stopped = true;
                 }
                 AllCoreStop();
-                active_thread = ThreadList()[0];
-                active_thread->Resume(Kernel::SuspendType::Debug);
+                UpdateActiveThread();
                 frontend->Stopped(active_thread);
                 break;
             }
             case DebuggerAction::Continue:
-                stepping = false;
+                active_thread->SetStepState(Kernel::StepState::NotStepping);
                 ResumeInactiveThreads();
                 AllCoreResume();
                 break;
-            case DebuggerAction::StepThread:
-                stepping = true;
+            case DebuggerAction::StepThreadUnlocked:
+                active_thread->SetStepState(Kernel::StepState::StepPending);
+                ResumeInactiveThreads();
+                AllCoreResume();
+                break;
+            case DebuggerAction::StepThreadLocked:
+                active_thread->SetStepState(Kernel::StepState::StepPending);
                 SuspendInactiveThreads();
                 AllCoreResume();
                 break;
@@ -212,10 +216,20 @@ private:
         for (auto* thread : ThreadList()) {
             if (thread != active_thread) {
                 thread->Resume(Kernel::SuspendType::Debug);
+                thread->SetStepState(Kernel::StepState::NotStepping);
             }
         }
     }
 
+    void UpdateActiveThread() {
+        const auto& threads{ThreadList()};
+        if (std::find(threads.begin(), threads.end(), active_thread) == threads.end()) {
+            active_thread = threads[0];
+        }
+        active_thread->Resume(Kernel::SuspendType::Debug);
+        active_thread->SetStepState(Kernel::StepState::NotStepping);
+    }
+
     const std::vector<Kernel::KThread*>& ThreadList() {
         return system.GlobalSchedulerContext().GetThreadList();
     }
@@ -233,7 +247,6 @@ private:
 
     Kernel::KThread* active_thread;
     bool stopped;
-    bool stepping;
 
     std::array<u8, 4096> client_data;
 };
@@ -252,8 +265,4 @@ bool Debugger::NotifyThreadStopped(Kernel::KThread* thread) {
     return impl && impl->NotifyThreadStopped(thread);
 }
 
-bool Debugger::IsStepping() const {
-    return impl && impl->IsStepping();
-}
-
 } // namespace Core
diff --git a/src/core/debugger/debugger.h b/src/core/debugger/debugger.h
index 7acd11815..ea36c6ab2 100644
--- a/src/core/debugger/debugger.h
+++ b/src/core/debugger/debugger.h
@@ -35,11 +35,6 @@ public:
      */
     bool NotifyThreadStopped(Kernel::KThread* thread);
 
-    /**
-     * Returns whether a step is in progress.
-     */
-    bool IsStepping() const;
-
 private:
     std::unique_ptr<DebuggerImpl> impl;
 };
diff --git a/src/core/debugger/debugger_interface.h b/src/core/debugger/debugger_interface.h
index 0b357fcb5..6ae3dc091 100644
--- a/src/core/debugger/debugger_interface.h
+++ b/src/core/debugger/debugger_interface.h
@@ -16,10 +16,11 @@ class KThread;
 namespace Core {
 
 enum class DebuggerAction {
-    Interrupt,         // Stop emulation as soon as possible.
-    Continue,          // Resume emulation.
-    StepThread,        // Step the currently-active thread.
-    ShutdownEmulation, // Shut down the emulator.
+    Interrupt,          ///< Stop emulation as soon as possible.
+    Continue,           ///< Resume emulation.
+    StepThreadLocked,   ///< Step the currently-active thread without resuming others.
+    StepThreadUnlocked, ///< Step the currently-active thread and resume others.
+    ShutdownEmulation,  ///< Shut down the emulator.
 };
 
 class DebuggerBackend {
diff --git a/src/core/debugger/gdbstub.cpp b/src/core/debugger/gdbstub.cpp
index 718c45952..44ebbe3e0 100644
--- a/src/core/debugger/gdbstub.cpp
+++ b/src/core/debugger/gdbstub.cpp
@@ -6,8 +6,7 @@
 #include <optional>
 #include <thread>
 
-#include <boost/asio.hpp>
-#include <boost/process/async_pipe.hpp>
+#include <boost/algorithm/string.hpp>
 
 #include "common/hex_util.h"
 #include "common/logging/log.h"
@@ -114,6 +113,11 @@ void GDBStub::ExecuteCommand(std::string_view packet, std::vector<DebuggerAction
         return;
     }
 
+    if (packet.starts_with("vCont")) {
+        HandleVCont(packet.substr(5), actions);
+        return;
+    }
+
     std::string_view command{packet.substr(1, packet.size())};
 
     switch (packet[0]) {
@@ -122,6 +126,8 @@ void GDBStub::ExecuteCommand(std::string_view packet, std::vector<DebuggerAction
         s64 thread_id{strtoll(command.data() + 1, nullptr, 16)};
         if (thread_id >= 1) {
             thread = GetThreadByID(thread_id);
+        } else {
+            thread = backend.GetActiveThread();
         }
 
         if (thread) {
@@ -141,6 +147,7 @@ void GDBStub::ExecuteCommand(std::string_view packet, std::vector<DebuggerAction
         }
         break;
     }
+    case 'Q':
     case 'q':
         HandleQuery(command);
         break;
@@ -204,7 +211,7 @@ void GDBStub::ExecuteCommand(std::string_view packet, std::vector<DebuggerAction
         break;
     }
     case 's':
-        actions.push_back(DebuggerAction::StepThread);
+        actions.push_back(DebuggerAction::StepThreadLocked);
         break;
     case 'C':
     case 'c':
@@ -248,12 +255,47 @@ void GDBStub::ExecuteCommand(std::string_view packet, std::vector<DebuggerAction
     }
 }
 
+static std::string_view GetThreadWaitReason(const Kernel::KThread* thread) {
+    switch (thread->GetWaitReasonForDebugging()) {
+    case Kernel::ThreadWaitReasonForDebugging::Sleep:
+        return "Sleep";
+    case Kernel::ThreadWaitReasonForDebugging::IPC:
+        return "IPC";
+    case Kernel::ThreadWaitReasonForDebugging::Synchronization:
+        return "Synchronization";
+    case Kernel::ThreadWaitReasonForDebugging::ConditionVar:
+        return "ConditionVar";
+    case Kernel::ThreadWaitReasonForDebugging::Arbitration:
+        return "Arbitration";
+    case Kernel::ThreadWaitReasonForDebugging::Suspended:
+        return "Suspended";
+    default:
+        return "Unknown";
+    }
+}
+
+static std::string GetThreadState(const Kernel::KThread* thread) {
+    switch (thread->GetState()) {
+    case Kernel::ThreadState::Initialized:
+        return "Initialized";
+    case Kernel::ThreadState::Waiting:
+        return fmt::format("Waiting ({})", GetThreadWaitReason(thread));
+    case Kernel::ThreadState::Runnable:
+        return "Runnable";
+    case Kernel::ThreadState::Terminated:
+        return "Terminated";
+    default:
+        return "Unknown";
+    }
+}
+
 void GDBStub::HandleQuery(std::string_view command) {
     if (command.starts_with("TStatus")) {
         // no tracepoint support
         SendReply("T0");
     } else if (command.starts_with("Supported")) {
-        SendReply("PacketSize=4000;qXfer:features:read+;qXfer:threads:read+;qXfer:libraries:read+");
+        SendReply("PacketSize=4000;qXfer:features:read+;qXfer:threads:read+;qXfer:libraries:read+;"
+                  "vContSupported+;QStartNoAckMode+");
     } else if (command.starts_with("Xfer:features:read:target.xml:")) {
         const auto offset{command.substr(30)};
         const auto amount{command.substr(command.find(',') + 1)};
@@ -297,18 +339,57 @@ void GDBStub::HandleQuery(std::string_view command) {
 
         const auto& threads = system.GlobalSchedulerContext().GetThreadList();
         for (const auto& thread : threads) {
-            buffer +=
-                fmt::format(R"(<thread id="{:x}" core="{:d}" name="Thread {:d}"/>)",
-                            thread->GetThreadID(), thread->GetActiveCore(), thread->GetThreadID());
+            buffer += fmt::format(R"(<thread id="{:x}" core="{:d}" name="Thread {:d}">{}</thread>)",
+                                  thread->GetThreadID(), thread->GetActiveCore(),
+                                  thread->GetThreadID(), GetThreadState(thread));
         }
 
         buffer += "</threads>";
         SendReply(buffer);
+    } else if (command.starts_with("Attached")) {
+        SendReply("0");
+    } else if (command.starts_with("StartNoAckMode")) {
+        no_ack = true;
+        SendReply(GDB_STUB_REPLY_OK);
     } else {
         SendReply(GDB_STUB_REPLY_EMPTY);
     }
 }
 
+void GDBStub::HandleVCont(std::string_view command, std::vector<DebuggerAction>& actions) {
+    if (command == "?") {
+        // Continuing and stepping are supported
+        // (signal is ignored, but required for GDB to use vCont)
+        SendReply("vCont;c;C;s;S");
+        return;
+    }
+
+    Kernel::KThread* stepped_thread{nullptr};
+    bool lock_execution{true};
+
+    std::vector<std::string> entries;
+    boost::split(entries, command.substr(1), boost::is_any_of(";"));
+    for (const auto& thread_action : entries) {
+        std::vector<std::string> parts;
+        boost::split(parts, thread_action, boost::is_any_of(":"));
+
+        if (parts.size() == 1 && (parts[0] == "c" || parts[0].starts_with("C"))) {
+            lock_execution = false;
+        }
+        if (parts.size() == 2 && (parts[0] == "s" || parts[0].starts_with("S"))) {
+            stepped_thread = GetThreadByID(strtoll(parts[1].data(), nullptr, 16));
+        }
+    }
+
+    if (stepped_thread) {
+        backend.SetActiveThread(stepped_thread);
+        actions.push_back(lock_execution ? DebuggerAction::StepThreadLocked
+                                         : DebuggerAction::StepThreadUnlocked);
+    } else {
+        actions.push_back(DebuggerAction::Continue);
+    }
+}
+
 Kernel::KThread* GDBStub::GetThreadByID(u64 thread_id) {
     const auto& threads{system.GlobalSchedulerContext().GetThreadList()};
     for (auto* thread : threads) {
@@ -374,6 +455,10 @@ void GDBStub::SendReply(std::string_view data) {
 }
 
 void GDBStub::SendStatus(char status) {
+    if (no_ack) {
+        return;
+    }
+
     std::array<u8, 1> buf = {static_cast<u8>(status)};
     LOG_TRACE(Debug_GDBStub, "Writing status: {}", status);
     backend.WriteToClient(buf);
diff --git a/src/core/debugger/gdbstub.h b/src/core/debugger/gdbstub.h
index b93a3a511..6f8ac2263 100644
--- a/src/core/debugger/gdbstub.h
+++ b/src/core/debugger/gdbstub.h
@@ -28,6 +28,7 @@ public:
 private:
     void ProcessData(std::vector<DebuggerAction>& actions);
     void ExecuteCommand(std::string_view packet, std::vector<DebuggerAction>& actions);
+    void HandleVCont(std::string_view command, std::vector<DebuggerAction>& actions);
     void HandleQuery(std::string_view command);
     std::vector<char>::const_iterator CommandEnd() const;
     std::optional<std::string> DetachCommand();
@@ -42,6 +43,7 @@ private:
     std::unique_ptr<GDBStubArch> arch;
     std::vector<char> current_command;
     std::map<VAddr, u32> replaced_instructions;
+    bool no_ack{};
 };
 
 } // namespace Core