// Protocol Buffers - Google's data interchange format

// Copyright 2008 Google Inc.  All rights reserved.

//

// Use of this source code is governed by a BSD-style

// license that can be found in the LICENSE file or at

// https://developers.google.com/open-source/licenses/bsd

// A common header that is included across all protobuf headers.  We do our best

// to avoid #defining any macros here; instead we generally put macros in

// port_def.inc and port_undef.inc so they are not visible from outside of

// protobuf.

#ifndef GOOGLE_PROTOBUF_PORT_H__

#define GOOGLE_PROTOBUF_PORT_H__

#include <cassert>

#include <cstddef>

#include <cstdint>

#include <new>

#include <string>

#include <type_traits>

#include <typeinfo>

#include "absl/base/config.h"

#include "absl/base/prefetch.h"

#include "absl/meta/type_traits.h"

#include "absl/strings/string_view.h"

#include "absl/types/optional.h"

// must be last

#include "google/protobuf/port_def.inc"

namespace google {

namespace protobuf {

class MessageLite;

namespace internal {

template <typename T>

inline PROTOBUF_ALWAYS_INLINE void StrongPointer(T* var) {

#if defined(__GNUC__)

  asm("" : : "r"(var));

#else

  auto volatile unused = var;

  (void)&unused;  // Use address to avoid an extra load of "unused".

#endif

}

// Similar to the overload above, but optimized for constant inputs.

template <typename T, T ptr>

inline PROTOBUF_ALWAYS_INLINE void StrongPointer() {

#if defined(__x86_64__) && defined(__linux__) && !defined(__APPLE__) &&     \

    !defined(__ANDROID__) && defined(__clang__) && __clang_major__ >= 19 && \

    !defined(PROTOBUF_INTERNAL_TEMPORARY_STRONG_POINTER_OPT_OUT)

  // This injects a relocation in the code path without having to run code, but

  // we can only do it with a newer clang.

  asm(".reloc ., BFD_RELOC_NONE, %p0" ::"Ws"(ptr));

#else

  StrongPointer(ptr);

#endif

}

template <typename T>

inline PROTOBUF_ALWAYS_INLINE void StrongReferenceToType() {

  constexpr auto ptr = T::template GetStrongPointerForType<T>();

#if defined(__cpp_nontype_template_args) && \

    __cpp_nontype_template_args >= 201411L

  // We can only use `ptr` as a template parameter since C++17

  return StrongPointer<decltype(ptr), ptr>();

#else

  return StrongPointer(ptr);

#endif

}

// See comments on `AllocateAtLeast` for information on size returning new.

struct SizedPtr {

  void* p;

  size_t n;

};

// Debug hook allowing setting up test scenarios for AllocateAtLeast usage.

using AllocateAtLeastHookFn = SizedPtr (*)(size_t, void*);

// `AllocAtLeastHook` API

constexpr bool HaveAllocateAtLeastHook();

void SetAllocateAtLeastHook(AllocateAtLeastHookFn fn, void* context = nullptr);

#if !defined(NDEBUG) && defined(ABSL_HAVE_THREAD_LOCAL) && \

    defined(__cpp_inline_variables)

// Hook data for current thread. These vars must not be accessed directly, use

// the 'HaveAllocateAtLeastHook()` and `SetAllocateAtLeastHook()` API instead.

inline thread_local AllocateAtLeastHookFn allocate_at_least_hook = nullptr;

inline thread_local void* allocate_at_least_hook_context = nullptr;

constexpr bool HaveAllocateAtLeastHook() { return true; }

inline void SetAllocateAtLeastHook(AllocateAtLeastHookFn fn, void* context) {

  allocate_at_least_hook = fn;

  allocate_at_least_hook_context = context;

}

#else  // !NDEBUG && ABSL_HAVE_THREAD_LOCAL && __cpp_inline_variables

constexpr bool HaveAllocateAtLeastHook() { return false; }

inline void SetAllocateAtLeastHook(AllocateAtLeastHookFn fn, void* context) {}

#endif  // !NDEBUG && ABSL_HAVE_THREAD_LOCAL && __cpp_inline_variables

// Allocates at least `size` bytes. This function follows the c++ language

// proposal from D0901R10 (http://wg21.link/D0901R10) and will be implemented

// in terms of the new operator new semantics when available. The allocated

// memory should be released by a call to `SizedDelete` or `::operator delete`.

inline SizedPtr AllocateAtLeast(size_t size) {

#if !defined(NDEBUG) && defined(ABSL_HAVE_THREAD_LOCAL) && \

    defined(__cpp_inline_variables)

  if (allocate_at_least_hook != nullptr) {

    return allocate_at_least_hook(size, allocate_at_least_hook_context);

  }

#endif  // !NDEBUG && ABSL_HAVE_THREAD_LOCAL && __cpp_inline_variables

  return {::operator new(size), size};

}

inline void SizedDelete(void* p, size_t size) {

#if defined(__cpp_sized_deallocation)

  ::operator delete(p, size);

#else

  // Avoid -Wunused-parameter

  (void)size;

  ::operator delete(p);

#endif

}

inline void SizedArrayDelete(void* p, size_t size) {

#if defined(__cpp_sized_deallocation)

  ::operator delete[](p, size);

#else

  // Avoid -Wunused-parameter

  (void)size;

  ::operator delete[](p);

#endif

}

// Tag type used to invoke the constinit constructor overload of classes

// such as ArenaStringPtr and MapFieldBase. Such constructors are internal

// implementation details of the library.

struct ConstantInitialized {

  explicit ConstantInitialized() = default;

};

// Tag type used to invoke the arena constructor overload of classes such

// as ExtensionSet and MapFieldLite in aggregate initialization. These

// classes typically don't have move/copy constructors, which rules out

// explicit initialization in pre-C++17.

struct ArenaInitialized {

  explicit ArenaInitialized() = default;

};

template <typename To, typename From>

inline To DownCast(From* f) {

  static_assert(

      std::is_base_of<From, typename std::remove_pointer<To>::type>::value,

      "illegal DownCast");

#if PROTOBUF_RTTI

  // RTTI: debug mode only!

  assert(f == nullptr || dynamic_cast<To>(f) != nullptr);

#endif

  return static_cast<To>(f);

}

template <typename ToRef, typename From>

inline ToRef DownCast(From& f) {

  using To = typename std::remove_reference<ToRef>::type;

  static_assert(std::is_base_of<From, To>::value, "illegal DownCast");

#if PROTOBUF_RTTI

  // RTTI: debug mode only!

  assert(dynamic_cast<To*>(&f) != nullptr);

#endif

  return *static_cast<To*>(&f);

}

// Looks up the name of `T` via RTTI, if RTTI is available.

template <typename T>

inline absl::optional<absl::string_view> RttiTypeName() {

#if PROTOBUF_RTTI

  return typeid(T).name();

#else

  return absl::nullopt;

#endif

}

// Helpers for identifying our supported types.

template <typename T>

struct is_supported_integral_type

    : absl::disjunction<std::is_same<T, int32_t>, std::is_same<T, uint32_t>,

                        std::is_same<T, int64_t>, std::is_same<T, uint64_t>,

                        std::is_same<T, bool>> {};

template <typename T>

struct is_supported_floating_point_type

    : absl::disjunction<std::is_same<T, float>, std::is_same<T, double>> {};

template <typename T>

struct is_supported_string_type

    : absl::disjunction<std::is_same<T, std::string>> {};

template <typename T>

struct is_supported_scalar_type

    : absl::disjunction<is_supported_integral_type<T>,

                        is_supported_floating_point_type<T>,

                        is_supported_string_type<T>> {};

template <typename T>

struct is_supported_message_type

    : absl::disjunction<std::is_base_of<MessageLite, T>> {

  static constexpr auto force_complete_type = sizeof(T);

};

// To prevent sharing cache lines between threads

#ifdef __cpp_aligned_new

enum { kCacheAlignment = 64 };

#else

enum { kCacheAlignment = alignof(max_align_t) };  // do the best we can

#endif

// The maximum byte alignment we support.

enum { kMaxMessageAlignment = 8 };

// Returns true if debug string hardening is required

inline constexpr bool DebugHardenStringValues() {

#ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING

  return true;

#else

  return false;

#endif

}

// Returns true if debug hardening for clearing oneof message on arenas is

// enabled.

inline constexpr bool DebugHardenClearOneofMessageOnArena() {

#ifdef NDEBUG

  return false;

#else

  return true;

#endif

}

// Returns true if pointers are 8B aligned, leaving least significant 3 bits

// available.

inline constexpr bool PtrIsAtLeast8BAligned() { return alignof(void*) >= 8; }

// Prefetch 5 64-byte cache line starting from 7 cache-lines ahead.

// Constants are somewhat arbitrary and pretty aggressive, but were

// chosen to give a better benchmark results. E.g. this is ~20%

// faster, single cache line prefetch is ~12% faster, increasing

// decreasing distance makes results 2-4% worse. Important note,

// prefetch doesn't require a valid address, so it is ok to prefetch

// past the end of message/valid memory, however we are doing this

// inside inline asm block, since computing the invalid pointer

// is a potential UB. Only insert prefetch once per function,

inline PROTOBUF_ALWAYS_INLINE void Prefetch5LinesFrom7Lines(const void* ptr) {

  PROTOBUF_PREFETCH_WITH_OFFSET(ptr, 448);

  PROTOBUF_PREFETCH_WITH_OFFSET(ptr, 512);

  PROTOBUF_PREFETCH_WITH_OFFSET(ptr, 576);

  PROTOBUF_PREFETCH_WITH_OFFSET(ptr, 640);

  PROTOBUF_PREFETCH_WITH_OFFSET(ptr, 704);

}

#if defined(NDEBUG) && ABSL_HAVE_BUILTIN(__builtin_unreachable)

[[noreturn]] ABSL_ATTRIBUTE_COLD PROTOBUF_ALWAYS_INLINE inline void

Unreachable() {

  __builtin_unreachable();

}

#elif ABSL_HAVE_BUILTIN(__builtin_FILE) && ABSL_HAVE_BUILTIN(__builtin_LINE)

[[noreturn]] ABSL_ATTRIBUTE_COLD inline void Unreachable(

    const char* file = __builtin_FILE(), int line = __builtin_LINE()) {

  protobuf_assumption_failed("Unreachable", file, line);

}

#else

[[noreturn]] ABSL_ATTRIBUTE_COLD inline void Unreachable() {

  protobuf_assumption_failed("Unreachable", "", 0);

}

#endif

#ifdef PROTOBUF_TSAN

// TODO: it would be preferable to use __tsan_external_read/

// __tsan_external_write, but they can cause dlopen issues.

template <typename T>

inline PROTOBUF_ALWAYS_INLINE void TSanRead(const T* impl) {

  char protobuf_tsan_dummy =

      *reinterpret_cast<const char*>(&impl->_tsan_detect_race);

  asm volatile("" : "+r"(protobuf_tsan_dummy));

}

// We currently use a dedicated member for TSan checking so the value of this

// member is not important. We can unconditionally write to it without affecting

// correctness of the rest of the class.

template <typename T>

inline PROTOBUF_ALWAYS_INLINE void TSanWrite(T* impl) {

  *reinterpret_cast<char*>(&impl->_tsan_detect_race) = 0;

}

#else

inline PROTOBUF_ALWAYS_INLINE void TSanRead(const void*) {}

inline PROTOBUF_ALWAYS_INLINE void TSanWrite(const void*) {}

#endif

// This trampoline allows calling from codegen without needing a #include to

// absl. It simplifies IWYU and deps.

inline void PrefetchToLocalCache(const void* ptr) {

  absl::PrefetchToLocalCache(ptr);

}

}  // namespace internal

}  // namespace protobuf

}  // namespace google

#include "google/protobuf/port_undef.inc"

#endif  // GOOGLE_PROTOBUF_PORT_H__