FEX-Emu--FEX/FEXCore/include/FEXCore/Debug/InternalThreadState.h

// SPDX-License-Identifier: MIT
#pragma once
#include <FEXCore/Core/Context.h>
#include <FEXCore/Core/CoreState.h>
#include <FEXCore/Core/SignalDelegator.h>
#include <FEXCore/Utils/Event.h>
#include <FEXCore/Utils/InterruptableConditionVariable.h>
#include <FEXCore/Utils/Threads.h>
#include <FEXCore/Utils/TypeDefines.h>
#include <FEXCore/fextl/memory.h>
#include <FEXCore/fextl/vector.h>

#include <chrono>
#include <shared_mutex>
#include <type_traits>

namespace FEXCore {
class LookupCache;
class CompileService;
} // namespace FEXCore

namespace FEXCore::Context {
class Context;
}

namespace FEXCore::CPU {
class CPUBackend;
union Relocation;
} // namespace FEXCore::CPU

namespace FEXCore::Frontend {
class Decoder;
}

namespace FEXCore::IR {
class OpDispatchBuilder;
class PassManager;
} // namespace FEXCore::IR

namespace FEXCore::Core {
struct DebugDataSubblock {
  uint32_t HostCodeOffset;
  uint32_t HostCodeSize;
};

struct DebugDataGuestOpcode {
  uint64_t GuestEntryOffset;
  ptrdiff_t HostEntryOffset;
};

/**
 * @brief Contains debug data for a block of code for later debugger analysis
 *
 * Needs to remain around for as long as the code could be executed at least
 */
struct DebugData : public FEXCore::Allocator::FEXAllocOperators {
  uint64_t HostCodeSize; ///< The size of the code generated in the host JIT
  fextl::vector<DebugDataSubblock> Subblocks;
  fextl::vector<DebugDataGuestOpcode> GuestOpcodes;
  fextl::vector<FEXCore::CPU::Relocation>* Relocations;
};

// Buffered JIT symbol tracking.
struct JITSymbolBuffer {
  // Maximum buffer size to ensure we are a page in size.
  constexpr static size_t BUFFER_SIZE = 4096 - (8 * 2);
  // Maximum distance until the end of the buffer to do a write.
  constexpr static size_t NEEDS_WRITE_DISTANCE = BUFFER_SIZE - 64;
  // Maximum time threshhold to wait before a buffer write occurs.
  constexpr static std::chrono::milliseconds MAXIMUM_THRESHOLD {100};

  JITSymbolBuffer()
    : LastWrite {std::chrono::steady_clock::now()} {}
  // stead_clock to ensure a monotonic increasing clock.
  // In highly stressed situations this can still cause >2% CPU time in vdso_clock_gettime.
  // If we need lower CPU time when JIT symbols are enabled then FEX can read the cycle counter directly.
  std::chrono::steady_clock::time_point LastWrite {};
  size_t Offset {};
  char Buffer[BUFFER_SIZE] {};
};
static_assert(sizeof(JITSymbolBuffer) == 4096, "Ensure this is one page in size");

struct InternalThreadState : public FEXCore::Allocator::FEXAllocOperators {
  FEXCore::Core::CpuStateFrame* const CurrentFrame = &BaseFrameState;

  struct {
    std::atomic_bool Running {false};
    std::atomic_bool WaitingToStart {true};
    std::atomic_bool EarlyExit {false};
    std::atomic_bool ThreadSleeping {false};
  } RunningEvents;

  FEXCore::Context::Context* CTX;
  std::atomic<SignalEvent> SignalReason {SignalEvent::Nothing};

  fextl::unique_ptr<FEXCore::Threads::Thread> ExecutionThread;
  bool StartPaused {false};
  InterruptableConditionVariable StartRunning;
  Event ThreadWaiting;

  fextl::unique_ptr<FEXCore::IR::OpDispatchBuilder> OpDispatcher;

  fextl::unique_ptr<FEXCore::CPU::CPUBackend> CPUBackend;
  fextl::unique_ptr<FEXCore::LookupCache> LookupCache;

  fextl::unique_ptr<FEXCore::Frontend::Decoder> FrontendDecoder;
  fextl::unique_ptr<FEXCore::IR::PassManager> PassManager;
  FEXCore::HLE::ThreadManagement ThreadManager;
  fextl::unique_ptr<JITSymbolBuffer> SymbolBuffer;

  int StatusCode {};
  FEXCore::Context::ExitReason ExitReason {FEXCore::Context::ExitReason::EXIT_WAITING};
  std::shared_ptr<FEXCore::CompileService> CompileService;

  std::shared_mutex ObjectCacheRefCounter {};

  struct DeferredSignalState {
#ifndef _WIN32
    siginfo_t Info;
#endif
    int Signal;
  };

  // Queue of thread local signal frames that have been deferred.
  // Async signals aren't guaranteed to be delivered in any particular order, but FEX treats them as FILO.
  fextl::vector<DeferredSignalState> DeferredSignalFrames;

  ///< Data pointer for exclusive use by the frontend
  void* FrontendPtr;

  // BaseFrameState should always be at the end, directly before the interrupt fault page
  alignas(16) FEXCore::Core::CpuStateFrame BaseFrameState {};

  // Can be reprotected as RO to trigger an interrupt at generated code block entrypoints
  alignas(FEXCore::Utils::FEX_PAGE_SIZE) uint8_t InterruptFaultPage[FEXCore::Utils::FEX_PAGE_SIZE];
};
static_assert(
  (offsetof(FEXCore::Core::InternalThreadState, InterruptFaultPage) - offsetof(FEXCore::Core::InternalThreadState, BaseFrameState)) < 4096,
  "Fault page is outside of immediate range from CPU state");
// static_assert(std::is_standard_layout<InternalThreadState>::value, "This needs to be standard layout");
} // namespace FEXCore::Core