FEX-Emu--FEX/FEXCore/Source/Interface/Context/Context.h

// SPDX-License-Identifier: MIT
#pragma once

#include "Common/JitSymbols.h"
#include "Interface/Core/CPUBackend.h"
#include "Interface/Core/CPUID.h"
#include "Interface/Core/SharedCodeBufferManager.h"
#include <Interface/IR/IntrusiveIRList.h>
#include <FEXCore/Config/Config.h>
#include <FEXCore/Core/Context.h>
#include <FEXCore/Core/CoreState.h>
#include <FEXCore/Core/HostFeatures.h>
#include <FEXCore/Core/DiskCache.h>
#include <FEXCore/IR/IR.h>
#include <FEXCore/Utils/CompilerDefs.h>
#include <FEXCore/Utils/SignalScopeGuards.h>
#include <FEXCore/fextl/memory.h>
#include <FEXCore/fextl/set.h>
#include <FEXCore/fextl/string.h>
#include <FEXCore/fextl/unordered_map.h>
#include <FEXCore/fextl/vector.h>

#include <atomic>
#include <cstddef>
#include <cstdint>
#include <mutex>
#include <optional>
#include <shared_mutex>

namespace FEXCore {
class SignalDelegator;
class ThunkHandler;
struct LookupCacheWriteLockToken;

namespace Core {
  struct DebugData;
  struct InternalThreadState;
} // namespace Core

namespace CPU {
  class Dispatcher;
} // namespace CPU

namespace HLE {
  class SourcecodeResolver;
  class SyscallHandler;
} // namespace HLE
} // namespace FEXCore

namespace FEXCore::Context {
struct FEX_PACKED ExitFunctionLinkData {
  uint64_t HostCode;
  uint64_t GuestRIP;
  int64_t CallerOffset;
};

struct CustomIRResult {
  void* Creator;
  void* Data;

  CustomIRResult(void* Creator, void* Data)
    : Creator(Creator)
    , Data(Data) {}
};

using BlockDelinkerFunc = void (*)(FEXCore::Context::ExitFunctionLinkData* Record);
constexpr uint32_t TSC_SCALE_MAXIMUM = 1'000'000'000; ///< 1Ghz

constexpr static bool BLOCK_DEBUGGING = false;

class CodeCache : public AbstractCodeCache {
public:
  CodeCache(ContextImpl&);
  ~CodeCache();

  ContextImpl& CTX;
  fextl::unique_ptr<ContextImpl> ValidationCTX;
  fextl::unique_ptr<Core::InternalThreadState> ValidationThread;
  FEXCore::Core::CPUState::gdt_segment ValidationGDT[32] {};
  bool IsGeneratingCache = false;

  FEX_CONFIG_OPT(EnableCodeCaching, ENABLECODECACHINGWIP);
  FEX_CONFIG_OPT(EnableLazyCodeCaching, ENABLELAZYCODECACHINGWIP);
  FEX_CONFIG_OPT(EnableCodeCacheValidation, ENABLECODECACHEVALIDATION);

  uint64_t ComputeCodeMapId(std::string_view Filename, int FD) override;
  bool SaveData(Core::InternalThreadState&, int TargetFD, const ExecutableFileSectionInfo&, uint64_t SerializedBaseAddress) override;

  fextl::unique_ptr<MappedCodeCacheFile> LoadCache(std::span<std::byte> CacheFile, const ExecutableFileInfo&, uint64_t FileStartVA) override;

  bool EnableLoadedSection(Core::InternalThreadState*, MappedCodeCacheFile&, const ExecutableFileSectionInfo&) override;

  void FinalizeCodePages(MappedCodeCacheFile&, std::span<std::byte> CodeRange) override;

  /**
   * Performs expensive extra validation on the loaded code cache data.
   *
   * This kicks off an in-process recompile of all cached blocks and compares
   * them with the cached data. Differences will be reported as fatal errors,
   * which can uncover bugs like for example:
   * - mismatches of the JIT configuration used during cache generation
   * - hidden position dependencies due to missing FEX relocations
   * - incorrect instruction padding
   */
  void Validate(const ExecutableFileSectionInfo&, fextl::set<uint64_t> GuestBlocks, const fextl::set<uint64_t>& HostBlocks,
                std::span<std::byte> CachedCode);

  void InitiateCacheGeneration() override {
    IsGeneratingCache = true;
  }

  /**
   * Applies a set of FEX relocations to the given code section.
   *
   * FEX relocations describe runtime-dependencies of FEX-generated code.
   * When loading a code cache, they are used to move cached code to the
   * dynamically chosen base address of the guest binary.
   *
   * Conversely, relocations are applied in reverse when writing code caches
   * to ensure consistency across generation runs.
   *
   * Note that FEX relocations are unrelated to ELF/PE relocations.
   *
   * @param GuestDelta Guest address offset to apply to RIP-relative data
   * @param ForStorage True for serializing data (producing deterministic output); false for de-serializing it (resolving dynamic symbols)
   *
   * @return Returns true on success
   */
  [[nodiscard]]
  bool ApplyCodeRelocations(uint64_t GuestDelta, std::span<std::byte> Code, std::span<const CPU::Relocation> Relocations, bool ForStorage);
};

class ContextImpl final : public FEXCore::Context::Context, public CPU::SharedCodeBufferManager {
public:
  // Context base class implementation.
  bool InitCore() override;

  void ExecuteThread(FEXCore::Core::InternalThreadState* Thread) override;

  bool CheckIfBlockIsCacheable(FEXCore::Core::InternalThreadState&, uint64_t GuestRIP, uint64_t MaxInst) override;
  void CompileRIP(FEXCore::Core::InternalThreadState* Thread, uint64_t GuestRIP) override;
  void CompileRIPCount(FEXCore::Core::InternalThreadState* Thread, uint64_t GuestRIP, uint64_t MaxInst) override;

  void HandleCallback(FEXCore::Core::InternalThreadState* Thread, uint64_t RIP) override;

  bool IsAddressInCurrentBlock(FEXCore::Core::InternalThreadState* Thread, uint64_t Address, uint64_t Size) override;
  bool IsCurrentBlockSingleInst(FEXCore::Core::InternalThreadState* Thread) override;
  uint64_t GetGuestBlockEntry(FEXCore::Core::InternalThreadState* Thread) override;

  uint64_t RestoreRIPFromHostPC(FEXCore::Core::InternalThreadState* Thread, uint64_t HostPC) override;
  uint32_t ReconstructCompactedEFLAGS(FEXCore::Core::InternalThreadState* Thread, bool WasInJIT, const uint64_t* HostGPRs, uint64_t PSTATE) override;
  void SetFlagsFromCompactedEFLAGS(FEXCore::Core::InternalThreadState* Thread, uint32_t EFLAGS) override;

  void ReconstructXMMRegisters(const FEXCore::Core::InternalThreadState* Thread, __uint128_t* XMM_Low, __uint128_t* YMM_High) override;
  void SetXMMRegistersFromState(FEXCore::Core::InternalThreadState* Thread, const __uint128_t* XMM_Low, const __uint128_t* YMM_High) override;

  /**
   * @brief Used to create FEX thread objects in preparation for creating a true OS thread.
   *
   * @param NewThreadState The initial thread state to setup for our state, if inheriting.
   *
   * @return The InternalThreadState object that tracks all of the emulated thread's state
   *
   * Usecases:
   *  Parent thread Creation:
   *    - Thread = CreateThread();
   *    - Thread->CurrentFrame->State.rip = InitialRIP;
   *    - Thread->CurrentFrame->State.gregs[FEXCore::X86State::REG_RSP] = InitialStack;
   *    - CTX->ExecuteThread(Thread);
   *  OS thread Creation:
   *    - Thread = CreateThread(NewState);
   *    - Thread->ExecutionThread = FEXCore::Threads::Thread::Create(ThreadHandler, Arg);
   *    - ThreadHandler calls `CTX->ExecuteThread(Thread)`
   *  OS fork (New thread created with a clone of thread state):
   *    - clone{2, 3}
   *    - Thread = CreateThread(CopyOfThreadState);
   *    - ExecuteThread(Thread); // Starts executing without creating another host thread
   *  Thunk callback executing guest code from native host thread
   *    - Thread = CreateThread(NewState);
   *    - HandleCallback(Thread, RIP);
   */

  FEXCore::Core::InternalThreadState* CreateThread(const FEXCore::Core::CPUState* NewThreadState) override;

  /**
   * @brief Destroys this FEX thread object and stops tracking it internally
   *
   * @param Thread The internal FEX thread state object
   */
  void DestroyThread(FEXCore::Core::InternalThreadState* Thread) override;

#ifndef _WIN32
  void LockBeforeFork(FEXCore::Core::InternalThreadState* Thread) override;
  void UnlockAfterFork(FEXCore::Core::InternalThreadState* Thread, bool Child) override;
#endif
  void SetSignalDelegator(FEXCore::SignalDelegator* SignalDelegation) override;
  void SetSyscallHandler(FEXCore::HLE::SyscallHandler* Handler) override;
  void SetThunkHandler(FEXCore::ThunkHandler* Handler) override;

  FEXCore::CPUID::FunctionResults RunCPUIDFunction(uint32_t Function, uint32_t Leaf) override;
  FEXCore::CPUID::XCRResults RunXCRFunction(uint32_t Function) override;
  FEXCore::CPUID::FunctionResults RunCPUIDFunctionName(uint32_t Function, uint32_t Leaf, uint32_t CPU) override;

  virtual void InitDiskCache() override {}

  CodeCache& GetCodeCache() override {
    return CodeCache;
  }

  void SetCodeMapWriter(fextl::unique_ptr<CodeMapWriter> Writer) override {
    CodeMapWriter = std::move(Writer);
  }

  void FlushAndCloseCodeMap() override {
    if (CodeMapWriter) {
      CodeMapWriter.reset();
    }
  }

  void OnCodeBufferAllocated(const std::shared_ptr<CPU::CodeBuffer>&) override;
  void ClearCodeCache(FEXCore::Core::InternalThreadState* Thread, bool NewCodeBuffer = true) override;
  void InvalidateCodeBuffersCodeRange(uint64_t Start, uint64_t Length) override;
  void InvalidateThreadCachedCodeRange(FEXCore::Core::InternalThreadState* Thread, uint64_t Start, uint64_t Length) override;
  FEXCore::Utils::WritePriorityMutex::Mutex& GetCodeInvalidationMutex() override {
    return CodeInvalidationMutex;
  }

  void ConfigureAOTGen(FEXCore::Core::InternalThreadState* Thread, fextl::set<uint64_t>* ExternalBranches, uint64_t SectionMaxAddress) override;

  bool IsAddressInCodeBuffer(FEXCore::Core::InternalThreadState* Thread, uintptr_t Address) const override;

  // returns false if a handler was already registered
  std::optional<CustomIRResult>
  AddCustomIREntrypoint(uintptr_t Entrypoint, CustomIREntrypointHandler Handler, void* Creator = nullptr, void* Data = nullptr);

  void AddThunkTrampolineIRHandler(uintptr_t Entrypoint, uintptr_t GuestThunkEntrypoint) override;

  void AddForceTSOInformation(const IntervalList<uint64_t>& ValidRanges, fextl::set<uint64_t>&& Instructions) override;

  void RemoveForceTSOInformation(uint64_t Address, uint64_t Size) override;

  void MarkMonoDetected() override {
    MonoDetected = true;
  }

  void MarkMonoBackpatcherBlock(uint64_t BlockEntry) override;

  // Manual debugging tooling which is useful for developers.
  struct TrackingEmpty {
    // RIP stepping handling
    virtual void AddSingleStepTarget(uint64_t GuestRIP) {}
    virtual void AddSingleStepTargetRange(uint64_t RIPBegin, uint64_t RipEnd) {}
    virtual void AllTargetSingleStep() {}
    virtual void RemoveSingleStepTarget(uint64_t GuestRIP) {}
    virtual bool IsSingleStepTarget(uint64_t GuestRIP) {
      return false;
    }

    // Watchpoints
    virtual void AddWriteWatchPoint(uint64_t Ptr) {}
    virtual void AddReadWatchPoint(uint64_t Ptr) {}
    virtual bool ContainsWriteWatchPoint(uint64_t Ptr, size_t Size) {
      return false;
    }
    virtual bool ContainsReadWatchPoint(uint64_t Ptr, size_t Size) {
      return false;
    }
  };

  struct TrackingPossible final : public TrackingEmpty {
    void AddSingleStepTarget(uint64_t GuestRIP) override {
      SingleStepTargets.emplace(GuestRIP);
    }

    virtual void AddSingleStepTargetRange(uint64_t RIPBegin, uint64_t RIPEnd) override {
      SingleStepRanges.emplace_back(Range {RIPBegin, RIPEnd});
    }

    void RemoveSingleStepTarget(uint64_t GuestRIP) override {
      SingleStepTargets.erase(GuestRIP);
    }

    void AllTargetSingleStep() override {
      SingleStepEverything = true;
    }

    bool IsSingleStepTarget(uint64_t GuestRIP) override {
      return SingleStepEverything || SingleStepTargets.contains(GuestRIP) || IsInRange(GuestRIP);
    }

    void AddWriteWatchPoint(uint64_t Ptr) override {
      WatchWriteTargets.emplace(Ptr);
    }

    void AddReadWatchPoint(uint64_t Ptr) override {
      WatchReadTargets.emplace(Ptr);
    }

    bool ContainsWriteWatchPoint(uint64_t Ptr, size_t Size) override {
      return ContainsRange(WatchWriteTargets, Ptr, Size);
    }

    bool ContainsReadWatchPoint(uint64_t Ptr, size_t Size) override {
      return ContainsRange(WatchReadTargets, Ptr, Size);
    }

  private:
    bool SingleStepEverything {};
    fextl::set<uint64_t> SingleStepTargets {};
    fextl::set<uint64_t> WatchWriteTargets {};
    fextl::set<uint64_t> WatchReadTargets {};
    struct Range {
      uint64_t Begin, End;
    };
    fextl::vector<Range> SingleStepRanges {};

    bool IsInRange(uint64_t RIP) const {
      return std::ranges::any_of(SingleStepRanges, [RIP](const auto& range) { return RIP >= range.Begin && RIP <= range.End; });
    }

    static bool ContainsRange(const fextl::set<uint64_t>& Set, uint64_t Ptr, size_t Size) {
      for (auto it = Set.lower_bound(Ptr); it != Set.end(); --it) {
        auto Watch = *it;
        if (Watch < Ptr) {
          break;
        }
        if (Watch >= Ptr && Watch < (Ptr + Size)) {
          return true;
        }
      }

      return false;
    }
  };
  using TrackingStructure = std::conditional<BLOCK_DEBUGGING, TrackingPossible, TrackingEmpty>::type;

  TrackingStructure BlockDebuggerTracker {};
public:
  struct {
    uint64_t VirtualMemSize {1ULL << 36};
    uint64_t TSCScale = 0;

    // Used if the JIT needs to have its interrupt fault code emitted.
    bool NeedsPendingInterruptFaultCheck {false};

    FEX_CONFIG_OPT(Multiblock, MULTIBLOCK);
    FEX_CONFIG_OPT(SingleStepConfig, SINGLESTEP);
    FEX_CONFIG_OPT(GdbServer, GDBSERVER);
    FEX_CONFIG_OPT(Is64BitMode, IS64BIT_MODE);
    FEX_CONFIG_OPT(TSOEnabled, TSOENABLED);
    FEX_CONFIG_OPT(VectorTSOEnabled, VECTORTSOENABLED);
    FEX_CONFIG_OPT(MemcpySetTSOEnabled, MEMCPYSETTSOENABLED);
    FEX_CONFIG_OPT(SMCChecks, SMCCHECKS);
    FEX_CONFIG_OPT(MaxInstPerBlock, MAXINST);
    FEX_CONFIG_OPT(RootFSPath, ROOTFS);
    FEX_CONFIG_OPT(GlobalJITNaming, GLOBALJITNAMING);
    FEX_CONFIG_OPT(LibraryJITNaming, LIBRARYJITNAMING);
    FEX_CONFIG_OPT(BlockJITNaming, BLOCKJITNAMING);
    FEX_CONFIG_OPT(GDBSymbols, GDBSYMBOLS);
    FEX_CONFIG_OPT(x87ReducedPrecision, X87REDUCEDPRECISION);
    FEX_CONFIG_OPT(DisableTelemetry, DISABLETELEMETRY);
    FEX_CONFIG_OPT(DisableVixlIndirectCalls, DISABLE_VIXL_INDIRECT_RUNTIME_CALLS);
    FEX_CONFIG_OPT(SmallTSCScale, SMALLTSCSCALE);
    FEX_CONFIG_OPT(StrictInProcessSplitLocks, STRICTINPROCESSSPLITLOCKS);
    FEX_CONFIG_OPT(MonoHacks, MONOHACKS);
  } Config;

  FEXCore::Utils::WritePriorityMutex::Mutex CodeInvalidationMutex {};

  uint32_t StrictSplitLockMutex {};

  FEXCore::HostFeatures HostFeatures;
  // CPUID depends on HostFeatures so needs to be initialized after that.
  FEXCore::CPUIDEmu CPUID;
  FEXCore::HLE::SyscallHandler* SyscallHandler {};
  FEXCore::HLE::SourcecodeResolver* SourcecodeResolver {};
  FEXCore::ThunkHandler* ThunkHandler {};
  fextl::unique_ptr<FEXCore::CPU::Dispatcher> Dispatcher;
  DiskCache::DiskCache DiskCache;
  CodeCache CodeCache;
  fextl::unique_ptr<CodeMapWriter> CodeMapWriter;

  SignalDelegator* SignalDelegation {};

  ContextImpl(const FEXCore::HostFeatures& Features);

  static void ThreadRemoveCodeEntryFromJit(FEXCore::Core::CpuStateFrame* Frame, uint64_t GuestRIP);

  // This is used as a replacement for the SMC writes in the mono callsite backpatcher that avoids atomic operations
  // (safe as the invalidation mutex is locked) and manually invalidates the modified range. Allowing SMC to be detected
  // even if faulting is disabled.
  static void MonoBackpatcherWrite(FEXCore::Core::CpuStateFrame* Frame, uint8_t Size, uint64_t Address, uint64_t Value);

  void RemoveCustomIREntrypoint(FEXCore::Core::InternalThreadState* Thread, uintptr_t Entrypoint);

  struct GenerateIRResult {
    std::optional<IR::IRListView> IRView;
    uint64_t TotalInstructions;
    uint64_t TotalInstructionsLength;
    uint64_t StartAddr;
    uint64_t Length;
    bool NeedsAddGuestCodeRanges;
  };
  [[nodiscard]]
  GenerateIRResult GenerateIR(FEXCore::Core::InternalThreadState* Thread, uint64_t GuestRIP, bool ExtendedDebugInfo, uint64_t MaxInst);

  struct CompileCodeResult {
    CPU::CPUBackend::CompiledCode CompiledCode;
    fextl::unique_ptr<FEXCore::Core::DebugData> DebugData;
    uint64_t StartAddr;
    uint64_t Length;
    bool NeedsAddGuestCodeRanges;
  };
  [[nodiscard]]
  CompileCodeResult CompileCode(FEXCore::Core::InternalThreadState* Thread, uint64_t GuestRIP, uint64_t MaxInst = 0);
  uintptr_t CompileBlock(FEXCore::Core::CpuStateFrame* Frame, uint64_t GuestRIP, uint64_t MaxInst = 0);
  uintptr_t CompileSingleStep(FEXCore::Core::CpuStateFrame* Frame, uint64_t GuestRIP);

  FEXCore::JITSymbols Symbols;

  FEXCore::Utils::PooledAllocatorVirtual OpDispatcherAllocator {"FEXMem_OpDispatcher"};
  FEXCore::Utils::PooledAllocatorVirtual FrontendAllocator {"FEXMem_Frontend"};
  FEXCore::Utils::PooledAllocatorVirtualWithGuard CPUBackendAllocator {"FEXMem_CPUBackend"};

  // If Atomic-based TSO emulation is enabled or not.
  bool IsAtomicTSOEnabled() const {
    return AtomicTSOEmulationEnabled;
  }

  // If atomic-based TSO emulation is enabled for vector operations.
  bool IsVectorAtomicTSOEnabled() const {
    return VectorAtomicTSOEmulationEnabled;
  }

  // If atomic-based TSO emulation is enabled for memcpy operations.
  bool IsMemcpyAtomicTSOEnabled() const {
    return MemcpyAtomicTSOEmulationEnabled;
  }

  void SetHardwareTSOSupport(bool HardwareTSOSupported) override {
    SupportsHardwareTSO = HardwareTSOSupported;
    UpdateAtomicTSOEmulationConfig();
  }

  void EnableExitOnHLT() override {
    ExitOnHLT = true;
  }

  bool ExitOnHLTEnabled() const {
    return ExitOnHLT;
  }

  bool AreMonoHacksActive() const {
    return Config.MonoHacks && MonoDetected;
  }

  bool RequiresRelocatableConstants() const;

protected:
  void UpdateAtomicTSOEmulationConfig() {
    if (SupportsHardwareTSO) {
      // If the hardware supports TSO then we don't need to emulate it through atomics.
      AtomicTSOEmulationEnabled = false;
      VectorAtomicTSOEmulationEnabled = false;
      MemcpyAtomicTSOEmulationEnabled = false;
    } else {
      AtomicTSOEmulationEnabled = Config.TSOEnabled;
      VectorAtomicTSOEmulationEnabled = Config.TSOEnabled && Config.VectorTSOEnabled;
      MemcpyAtomicTSOEmulationEnabled = Config.TSOEnabled && Config.MemcpySetTSOEnabled;
    }
  }

private:
  /**
   * @brief Initializes the JIT compilers for the thread
   *
   * @param State The internal FEX thread state object
   *
   * InitializeCompiler is called inside of CreateThread, so you likely don't need this
   */
  void InitializeCompiler(FEXCore::Core::InternalThreadState* Thread);

  bool SupportsHardwareTSO = false;
  bool AtomicTSOEmulationEnabled = true;
  bool VectorAtomicTSOEmulationEnabled = false;
  bool MemcpyAtomicTSOEmulationEnabled = false;

  bool ExitOnHLT = false;
  FEX_CONFIG_OPT(AppFilename, APP_FILENAME);

  std::shared_mutex CustomIRMutex;
  std::atomic<bool> HasCustomIRHandlers {};
  struct CustomIRHandlerEntry final {
    CustomIREntrypointHandler Handler;
    void* Creator;
    void* Data;
  };
  fextl::unordered_map<uint64_t, CustomIRHandlerEntry> CustomIRHandlers;
  IntervalList<uint64_t> ForceTSOValidRanges; // The ranges for which ForceTSOInstructions has populated data
  fextl::set<uint64_t> ForceTSOInstructions;

  bool MonoDetected = false;
  std::atomic<uint64_t> MonoBackpatcherBlock;

  std::mutex CodeBufferListLock;
  fextl::vector<std::weak_ptr<CPU::CodeBuffer>> CodeBufferList;
};
} // namespace FEXCore::Context