path: root/libbase/include/core/compiler/Compiler.h

/*
 RCC-Project

 Copyright (C) 2026 Richard Qin

 This file is part of RCC-Project.

 RCC-Project is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free
 Software Foundation; either version 3 of the License, or (at your option) any
 later version.

 RCC-Project is distributed in the hope that it will be useful, but WITHOUT ANY
 WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
 A PARTICULAR PURPOSE.  See the GNU General Public License for more details.

 You should have received a copy of the GNU General Public License along with
 RCC-Project; see the file COPYING.  If not see
 <http://www.gnu.org/licenses/>.
*/

//===-- core/compiler/Compiler.h - Compiler abstraction support --*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file defines several macros, based on the current compiler.  This allows
// use of compiler-specific features in a way that remains portable. This header
// can be included from either C or C++.
//
//===----------------------------------------------------------------------===//

#ifndef LIBBASE_CORE_COMPILER_H
#define LIBBASE_CORE_COMPILER_H

#include "core/config/libbase-config.h"

#include <stddef.h>

#if defined(_MSC_VER)
#include <sal.h>
#endif

#ifndef __has_feature
# define __has_feature(x) 0
#endif

#ifndef __has_extension
# define __has_extension(x) 0
#endif

#ifndef __has_attribute
# define __has_attribute(x) 0
#endif

#ifndef __has_builtin
# define __has_builtin(x) 0
#endif

#ifndef __has_warning
# define __has_warning(x) 0
#endif

// Only use __has_cpp_attribute in C++ mode. GCC defines __has_cpp_attribute in
// C mode, but the :: in __has_cpp_attribute(scoped::attribute) is invalid.
#ifndef LIBBASE_HAS_CPP_ATTRIBUTE
#if defined(__cplusplus) && defined(__has_cpp_attribute)
# define LIBBASE_HAS_CPP_ATTRIBUTE(x) __has_cpp_attribute(x)
#else
# define LIBBASE_HAS_CPP_ATTRIBUTE(x) 0
#endif
#endif

/// \macro LIBBASE_GNUC_PREREQ
/// Extend the default __GNUC_PREREQ even if glibc's features.h isn't
/// available.
#ifndef LIBBASE_GNUC_PREREQ
# if defined(__GNUC__) && defined(__GNUC_MINOR__) && defined(__GNUC_PATCHLEVEL__)
#  define LIBBASE_GNUC_PREREQ(maj, min, patch) \
    ((__GNUC__ << 20) + (__GNUC_MINOR__ << 10) + __GNUC_PATCHLEVEL__ >= \
     ((maj) << 20) + ((min) << 10) + (patch))
# elif defined(__GNUC__) && defined(__GNUC_MINOR__)
#  define LIBBASE_GNUC_PREREQ(maj, min, patch) \
    ((__GNUC__ << 20) + (__GNUC_MINOR__ << 10) >= ((maj) << 20) + ((min) << 10))
# else
#  define LIBBASE_GNUC_PREREQ(maj, min, patch) 0
# endif
#endif

/// \macro LIBBASE_MSC_PREREQ
/// Is the compiler MSVC of at least the specified version?
/// The common \param version values to check for are:
/// * 1910: VS2017, version 15.1 & 15.2
/// * 1911: VS2017, version 15.3 & 15.4
/// * 1912: VS2017, version 15.5
/// * 1913: VS2017, version 15.6
/// * 1914: VS2017, version 15.7
/// * 1915: VS2017, version 15.8
/// * 1916: VS2017, version 15.9
/// * 1920: VS2019, version 16.0
/// * 1921: VS2019, version 16.1
/// * 1922: VS2019, version 16.2
/// * 1923: VS2019, version 16.3
/// * 1924: VS2019, version 16.4
/// * 1925: VS2019, version 16.5
/// * 1926: VS2019, version 16.6
/// * 1927: VS2019, version 16.7
/// * 1928: VS2019, version 16.8 + 16.9
/// * 1929: VS2019, version 16.10 + 16.11
/// * 1930: VS2022, version 17.0
#ifdef _MSC_VER
#define LIBBASE_MSC_PREREQ(version) (_MSC_VER >= (version))

// We require at least VS 2019.
#if !defined(LIBBASE_FORCE_USE_OLD_TOOLCHAIN)
#if !LIBBASE_MSC_PREREQ(1920)
#error LLVM requires at least VS 2019.
#endif
#endif

#else
#define LIBBASE_MSC_PREREQ(version) 0
#endif

/// LIBBASE_LIBRARY_VISIBILITY - If a class marked with this attribute is linked
/// into a shared library, then the class should be private to the library and
/// not accessible from outside it.  Can also be used to mark variables and
/// functions, making them private to any shared library they are linked into.
/// On PE/COFF targets, library visibility is the default, so this isn't needed.
///
/// LIBBASE_EXTERNAL_VISIBILITY - classes, functions, and variables marked with
/// this attribute will be made public and visible outside of any shared library
/// they are linked in to.

#if LIBBASE_HAS_CPP_ATTRIBUTE(gnu::visibility) && defined(__GNUC__) &&            \
    !defined(__clang__)
#define LIBBASE_ATTRIBUTE_VISIBILITY_HIDDEN [[gnu::visibility("hidden")]]
#define LIBBASE_ATTRIBUTE_VISIBILITY_DEFAULT [[gnu::visibility("default")]]
#elif __has_attribute(visibility)
#define LIBBASE_ATTRIBUTE_VISIBILITY_HIDDEN __attribute__((visibility("hidden")))
#define LIBBASE_ATTRIBUTE_VISIBILITY_DEFAULT __attribute__((visibility("default")))
#else
#define LIBBASE_ATTRIBUTE_VISIBILITY_HIDDEN
#define LIBBASE_ATTRIBUTE_VISIBILITY_DEFAULT
#endif

#if defined(LIBBASE_BUILD_SHARED_LIBS)
#define LIBBASE_EXTERNAL_VISIBILITY LIBBASE_ATTRIBUTE_VISIBILITY_DEFAULT
#else
#define LIBBASE_EXTERNAL_VISIBILITY
#endif

#if (!(defined(_WIN32) || defined(__CYGWIN__)) ||                              \
     ((defined(__MINGW32__) || defined(__CYGWIN__)) && defined(__clang__)))
#define LIBBASE_LIBRARY_VISIBILITY LIBBASE_ATTRIBUTE_VISIBILITY_HIDDEN
// Clang compilers older then 15 do not support gnu style attributes on
// namespaces.
#if defined(__clang__) && __clang_major__ < 15
#define LIBBASE_LIBRARY_VISIBILITY_NAMESPACE [[gnu::visibility("hidden")]]
#else
#define LIBBASE_LIBRARY_VISIBILITY_NAMESPACE LIBBASE_ATTRIBUTE_VISIBILITY_HIDDEN
#endif
#define LIBBASE_ALWAYS_EXPORT LIBBASE_ATTRIBUTE_VISIBILITY_DEFAULT
#elif defined(_WIN32)
#define LIBBASE_ALWAYS_EXPORT __declspec(dllexport)
#define LIBBASE_LIBRARY_VISIBILITY
#define LIBBASE_LIBRARY_VISIBILITY_NAMESPACE
#else
#define LIBBASE_LIBRARY_VISIBILITY
#define LIBBASE_ALWAYS_EXPORT
#define LIBBASE_LIBRARY_VISIBILITY_NAMESPACE
#endif

/// LIBBASE_ABI is the main export/visibility macro to mark something as explicitly
/// exported when llvm is built as a shared library with everything else that is
/// unannotated will have internal visibility.
///
/// LIBBASE_ABI_EXPORT is for the special case for things like plugin symbol
/// declarations or definitions where we don't want the macro to be switching
/// between dllexport and dllimport on windows based on what codebase is being
/// built, it will only be dllexport. For non windows platforms this macro
/// behaves the same as LIBBASE_ABI.
///
/// LIBBASE_EXPORT_TEMPLATE is used on explicit template instantiations in source
/// files that were declared extern in a header. This macro is only set as a
/// compiler export attribute on windows, on other platforms it does nothing.
///
/// LIBBASE_TEMPLATE_ABI is for annotating extern template declarations in headers
/// for both functions and classes. On windows its turned in to dllimport for
/// library consumers, for other platforms its a default visibility attribute.
///
/// LIBBASE_ABI_FOR_TEST is for annotating symbols that are exported from a
/// library-internal header solely so that unit tests can link against them.
/// Symbols in LLVM's public headers are part of the LLVM public interface and
/// should use LIBBASE_ABI. LIBBASE_ABI_FOR_TEST is reserved for internal headers,
/// whose symbols could be conditionally excluded when not building tests in the
/// future.
///
#ifndef LIBBASE_ABI_GENERATING_ANNOTATIONS
// Marker to add to classes or functions in public headers that should not have
// export macros added to them by the clang tool
#define LIBBASE_ABI_NOT_EXPORTED
// TODO(https://github.com/llvm/llvm-project/issues/145406): eliminate need for
// two preprocessor definitions to gate LIBBASE_ABI macro definitions.
#if defined(LIBBASE_ENABLE_EXPORT_ANNOTATIONS) && !defined(LIBBASE_BUILD_STATIC)
#if defined(_WIN32) && !defined(__MINGW32__)
#if defined(LIBBASE_EXPORTS)
#define LIBBASE_ABI __declspec(dllexport)
#define LIBBASE_TEMPLATE_ABI
#define LIBBASE_EXPORT_TEMPLATE __declspec(dllexport)
#else
#define LIBBASE_ABI __declspec(dllimport)
#define LIBBASE_TEMPLATE_ABI __declspec(dllimport)
#define LIBBASE_EXPORT_TEMPLATE
#endif
#define LIBBASE_ABI_EXPORT __declspec(dllexport)
#elif __has_attribute(visibility)
#if defined(__ELF__) || defined(__MINGW32__) || defined(_AIX) ||               \
    defined(__MVS__) || defined(__CYGWIN__)
#define LIBBASE_ABI __attribute__((visibility("default")))
#define LIBBASE_TEMPLATE_ABI LIBBASE_ABI
#define LIBBASE_EXPORT_TEMPLATE
#define LIBBASE_ABI_EXPORT LIBBASE_ABI
#elif defined(__MACH__) || defined(__wasm__) || defined(__EMSCRIPTEN__)
#define LIBBASE_ABI __attribute__((visibility("default")))
#define LIBBASE_TEMPLATE_ABI
#define LIBBASE_EXPORT_TEMPLATE
#define LIBBASE_ABI_EXPORT LIBBASE_ABI
#endif
#endif
#endif
#if !defined(LIBBASE_ABI)
#define LIBBASE_ABI
#define LIBBASE_TEMPLATE_ABI
#define LIBBASE_EXPORT_TEMPLATE
#define LIBBASE_ABI_EXPORT
#endif
#define LIBBASE_ABI_FOR_TEST LIBBASE_ABI
#endif

#if defined(__GNUC__)
#define LIBBASE_PREFETCH(addr, rw, locality) __builtin_prefetch(addr, rw, locality)
#else
#define LIBBASE_PREFETCH(addr, rw, locality)
#endif

#if __has_attribute(uninitialized)
#define LIBBASE_ATTRIBUTE_UNINITIALIZED __attribute__((uninitialized))
#else
#define LIBBASE_ATTRIBUTE_UNINITIALIZED
#endif

#if __has_attribute(used)
#define LIBBASE_ATTRIBUTE_USED __attribute__((__used__))
#else
#define LIBBASE_ATTRIBUTE_USED
#endif

#if __has_attribute(warn_unused)
#define LIBBASE_ATTRIBUTE_WARN_UNUSED __attribute__((warn_unused))
#else
#define LIBBASE_ATTRIBUTE_WARN_UNUSED
#endif

// Only enabled for clang:
// See https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99587
// GCC may produce "warning: 'retain' attribute ignored" (despite
// __has_attribute(retain) being 1).
#if defined(__clang__) && __has_attribute(retain)
#define LIBBASE_ATTRIBUTE_RETAIN __attribute__((__retain__))
#else
#define LIBBASE_ATTRIBUTE_RETAIN
#endif

// For deprecations that are not a simple rename, use [[deprecated(MSG)]]
// instead.
#if defined(__clang__)
#define LIBBASE_DEPRECATED_WITH_FIXIT(MSG, FIX)                                   \
  __attribute__((deprecated(MSG, FIX)))
#else
#define LIBBASE_DEPRECATED_WITH_FIXIT(MSG, FIX) [[deprecated(MSG)]]
#endif

// clang-format off
#if defined(__clang__) || defined(__GNUC__)
#define LIBBASE_SUPPRESS_DEPRECATED_DECLARATIONS_PUSH                             \
  _Pragma("GCC diagnostic push")                                               \
  _Pragma("GCC diagnostic ignored \"-Wdeprecated-declarations\"")
#define LIBBASE_SUPPRESS_DEPRECATED_DECLARATIONS_POP                              \
  _Pragma("GCC diagnostic pop")
#elif defined(_MSC_VER)
#define LIBBASE_SUPPRESS_DEPRECATED_DECLARATIONS_PUSH                             \
  __pragma(warning(push))                                                     \
  __pragma(warning(disable : 4996))
#define LIBBASE_SUPPRESS_DEPRECATED_DECLARATIONS_POP                              \
  __pragma(warning(pop))
#else
#define LIBBASE_SUPPRESS_DEPRECATED_DECLARATIONS_PUSH
#define LIBBASE_SUPPRESS_DEPRECATED_DECLARATIONS_POP
#endif
// clang-format on

// Indicate that a non-static, non-const C++ member function reinitializes
// the entire object to a known state, independent of the previous state of
// the object.
//
// The clang-tidy check bugprone-use-after-move recognizes this attribute as a
// marker that a moved-from object has left the indeterminate state and can be
// reused.
#if LIBBASE_HAS_CPP_ATTRIBUTE(clang::reinitializes)
#define LIBBASE_ATTRIBUTE_REINITIALIZES [[clang::reinitializes]]
#else
#define LIBBASE_ATTRIBUTE_REINITIALIZES
#endif

// Some compilers warn about unused functions. When a function is sometimes
// used or not depending on build settings (e.g. a function only called from
// within "assert"), this attribute can be used to suppress such warnings.
//
// However, it shouldn't be used for unused *variables*, as those have a much
// more portable solution:
//   (void)unused_var_name;
// Prefer cast-to-void wherever it is sufficient.
#if __has_attribute(unused)
#define LIBBASE_ATTRIBUTE_UNUSED __attribute__((__unused__))
#else
#define LIBBASE_ATTRIBUTE_UNUSED
#endif

// FIXME: Provide this for PE/COFF targets.
#if __has_attribute(weak) && !defined(__MINGW32__) && !defined(__CYGWIN__) &&  \
    !defined(_WIN32)
#define LIBBASE_HAS_ATTRIBUTE_WEAK 1
#else
#define LIBBASE_HAS_ATTRIBUTE_WEAK 0
#endif
#if LIBBASE_HAS_ATTRIBUTE_WEAK
#define LIBBASE_ATTRIBUTE_WEAK __attribute__((__weak__))
#else
#define LIBBASE_ATTRIBUTE_WEAK
#endif

// Prior to clang 3.2, clang did not accept any spelling of
// __has_attribute(const), so assume it is supported.
#if defined(__clang__) || defined(__GNUC__)
// aka 'CONST' but following LLVM Conventions.
#define LIBBASE_READNONE __attribute__((__const__))
#else
#define LIBBASE_READNONE
#endif

#if __has_attribute(pure) || defined(__GNUC__)
// aka 'PURE' but following LLVM Conventions.
#define LIBBASE_READONLY __attribute__((__pure__))
#else
#define LIBBASE_READONLY
#endif

#if __has_attribute(minsize)
#define LIBBASE_ATTRIBUTE_MINSIZE __attribute__((minsize))
#else
#define LIBBASE_ATTRIBUTE_MINSIZE
#endif

#if __has_builtin(__builtin_expect) || defined(__GNUC__)
#define LIBBASE_LIKELY(EXPR) __builtin_expect((bool)(EXPR), true)
#define LIBBASE_UNLIKELY(EXPR) __builtin_expect((bool)(EXPR), false)
#else
#define LIBBASE_LIKELY(EXPR) (EXPR)
#define LIBBASE_UNLIKELY(EXPR) (EXPR)
#endif

/// LIBBASE_ATTRIBUTE_NOINLINE - On compilers where we have a directive to do so,
/// mark a method "not for inlining".
#if __has_attribute(noinline)
#define LIBBASE_ATTRIBUTE_NOINLINE __attribute__((noinline))
#elif defined(_MSC_VER)
#define LIBBASE_ATTRIBUTE_NOINLINE __declspec(noinline)
#else
#define LIBBASE_ATTRIBUTE_NOINLINE
#endif

/// LIBBASE_ATTRIBUTE_ALWAYS_INLINE - On compilers where we have a directive to do
/// so, mark a method "always inline" because it is performance sensitive.
#if __has_attribute(always_inline)
#define LIBBASE_ATTRIBUTE_ALWAYS_INLINE inline __attribute__((always_inline))
#elif defined(_MSC_VER)
#define LIBBASE_ATTRIBUTE_ALWAYS_INLINE __forceinline
#else
#define LIBBASE_ATTRIBUTE_ALWAYS_INLINE inline
#endif

/// LIBBASE_ATTRIBUTE_ALWAYS_INLINE_UNLESS_DEBUG - Like
/// LIBBASE_ATTRIBUTE_ALWAYS_INLINE but disabled in debug builds to avoid stack
/// overflow with deep recursion.
#if defined(NDEBUG)
#define LIBBASE_ATTRIBUTE_ALWAYS_INLINE_UNLESS_DEBUG LIBBASE_ATTRIBUTE_ALWAYS_INLINE
#else
#define LIBBASE_ATTRIBUTE_ALWAYS_INLINE_UNLESS_DEBUG inline
#endif

/// LIBBASE_ATTRIBUTE_NO_DEBUG - On compilers where we have a directive to do
/// so, mark a method "no debug" because debug info makes the debugger
/// experience worse.
#if __has_attribute(nodebug)
#define LIBBASE_ATTRIBUTE_NODEBUG __attribute__((nodebug))
#else
#define LIBBASE_ATTRIBUTE_NODEBUG
#endif

#if __has_attribute(returns_nonnull)
#define LIBBASE_ATTRIBUTE_RETURNS_NONNULL __attribute__((returns_nonnull))
#elif defined(_MSC_VER)
#define LIBBASE_ATTRIBUTE_RETURNS_NONNULL _Ret_notnull_
#else
#define LIBBASE_ATTRIBUTE_RETURNS_NONNULL
#endif

/// LIBBASE_ATTRIBUTE_RESTRICT - Annotates a pointer to tell the compiler that
/// it is not aliased in the current scope.
#if defined(__clang__) || defined(__GNUC__) || defined(_MSC_VER)
#define LIBBASE_ATTRIBUTE_RESTRICT __restrict
#else
#define LIBBASE_ATTRIBUTE_RESTRICT
#endif

/// \macro LIBBASE_ATTRIBUTE_RETURNS_NOALIAS Used to mark a function as returning a
/// pointer that does not alias any other valid pointer.
#ifdef __GNUC__
#define LIBBASE_ATTRIBUTE_RETURNS_NOALIAS __attribute__((__malloc__))
#elif defined(_MSC_VER)
#define LIBBASE_ATTRIBUTE_RETURNS_NOALIAS __declspec(restrict)
#else
#define LIBBASE_ATTRIBUTE_RETURNS_NOALIAS
#endif

/// LIBBASE_FALLTHROUGH - Mark fallthrough cases in switch statements.
#if defined(__cplusplus) && __cplusplus > 201402L && LIBBASE_HAS_CPP_ATTRIBUTE(fallthrough)
#define LIBBASE_FALLTHROUGH [[fallthrough]]
#elif LIBBASE_HAS_CPP_ATTRIBUTE(gnu::fallthrough)
#define LIBBASE_FALLTHROUGH [[gnu::fallthrough]]
#elif __has_attribute(fallthrough)
#define LIBBASE_FALLTHROUGH __attribute__((fallthrough))
#elif LIBBASE_HAS_CPP_ATTRIBUTE(clang::fallthrough)
#define LIBBASE_FALLTHROUGH [[clang::fallthrough]]
#else
#define LIBBASE_FALLTHROUGH
#endif

/// LIBBASE_REQUIRE_CONSTANT_INITIALIZATION - Apply this to globals to ensure that
/// they are constant initialized.
#if LIBBASE_HAS_CPP_ATTRIBUTE(clang::require_constant_initialization)
#define LIBBASE_REQUIRE_CONSTANT_INITIALIZATION                                   \
  [[clang::require_constant_initialization]]
#else
#define LIBBASE_REQUIRE_CONSTANT_INITIALIZATION
#endif

/// LIBBASE_GSL_OWNER - Apply this to owning classes like SmallVector to enable
/// lifetime warnings.
#if LIBBASE_HAS_CPP_ATTRIBUTE(gsl::Owner)
#define LIBBASE_GSL_OWNER [[gsl::Owner]]
#else
#define LIBBASE_GSL_OWNER
#endif

/// LIBBASE_GSL_POINTER - Apply this to non-owning classes like
/// StringRef to enable lifetime warnings.
#if LIBBASE_HAS_CPP_ATTRIBUTE(gsl::Pointer)
#define LIBBASE_GSL_POINTER [[gsl::Pointer]]
#else
#define LIBBASE_GSL_POINTER
#endif

#if LIBBASE_HAS_CPP_ATTRIBUTE(clang::lifetimebound)
#define LIBBASE_LIFETIME_BOUND [[clang::lifetimebound]]
#else
#define LIBBASE_LIFETIME_BOUND
#endif

#if LIBBASE_HAS_CPP_ATTRIBUTE(nodiscard) >= 201907L
#define LIBBASE_CTOR_NODISCARD [[nodiscard]]
#else
#define LIBBASE_CTOR_NODISCARD
#endif

// Macro to suppress the MSVC warning C4848:
// "support for attribute [[msvc::no_unique_address]] in C++17 and earlier
// is a vendor extension".
// This warning is removed in versions >= 19.43.
#if !defined(_MSC_VER) || _MSC_VER >= 1943 || defined(__clang__)
#define LIBBASE_SUPPRESS_MSVC_ATTR_IS_VENDOR_EXT_PUSH
#define LIBBASE_SUPPRESS_MSVC_ATTR_IS_VENDOR_EXT_POP
#else // MSVC < 19.43
#define LIBBASE_SUPPRESS_MSVC_ATTR_IS_VENDOR_EXT_PUSH                             \
  __pragma(warning(push)) __pragma(warning(disable : 4848))
#define LIBBASE_SUPPRESS_MSVC_ATTR_IS_VENDOR_EXT_POP __pragma(warning(pop))
#endif

#if LIBBASE_HAS_CPP_ATTRIBUTE(no_unique_address)
#define LIBBASE_NO_UNIQUE_ADDRESS [[no_unique_address]]
#elif LIBBASE_HAS_CPP_ATTRIBUTE(msvc::no_unique_address)
#define LIBBASE_NO_UNIQUE_ADDRESS                                                 \
  LIBBASE_SUPPRESS_MSVC_ATTR_IS_VENDOR_EXT_PUSH                                   \
  [[msvc::no_unique_address]] LIBBASE_SUPPRESS_MSVC_ATTR_IS_VENDOR_EXT_POP
#else
#define LIBBASE_NO_UNIQUE_ADDRESS
#endif

/// LIBBASE_EXTENSION - Support compilers where we have a keyword to suppress
/// pedantic diagnostics.
#ifdef __GNUC__
#define LIBBASE_EXTENSION __extension__
#else
#define LIBBASE_EXTENSION
#endif

/// LIBBASE_BUILTIN_UNREACHABLE - On compilers which support it, expands
/// to an expression which states that it is undefined behavior for the
/// compiler to reach this point.  Otherwise is not defined.
///
/// '#else' is intentionally left out so that other macro logic (e.g.,
/// LIBBASE_ASSUME_ALIGNED and llvm_unreachable()) can detect whether
/// LIBBASE_BUILTIN_UNREACHABLE has a definition.
#if __has_builtin(__builtin_unreachable) || defined(__GNUC__)
# define LIBBASE_BUILTIN_UNREACHABLE __builtin_unreachable()
#elif defined(_MSC_VER)
# define LIBBASE_BUILTIN_UNREACHABLE __assume(false)
#endif

/// LIBBASE_BUILTIN_TRAP - On compilers which support it, expands to an expression
/// which causes the program to exit abnormally.
#if __has_builtin(__builtin_trap) || defined(__GNUC__)
# define LIBBASE_BUILTIN_TRAP __builtin_trap()
#elif defined(_MSC_VER)
// The __debugbreak intrinsic is supported by MSVC, does not require forward
// declarations involving platform-specific typedefs (unlike RaiseException),
// results in a call to vectored exception handlers, and encodes to a short
// instruction that still causes the trapping behavior we want.
# define LIBBASE_BUILTIN_TRAP __debugbreak()
#else
# define LIBBASE_BUILTIN_TRAP *(volatile int*)0x11 = 0
#endif

/// LIBBASE_BUILTIN_DEBUGTRAP - On compilers which support it, expands to
/// an expression which causes the program to break while running
/// under a debugger.
#if __has_builtin(__builtin_debugtrap)
# define LIBBASE_BUILTIN_DEBUGTRAP __builtin_debugtrap()
#elif defined(_MSC_VER)
// The __debugbreak intrinsic is supported by MSVC and breaks while
// running under the debugger, and also supports invoking a debugger
// when the OS is configured appropriately.
# define LIBBASE_BUILTIN_DEBUGTRAP __debugbreak()
#else
// Just continue execution when built with compilers that have no
// support. This is a debugging aid and not intended to force the
// program to abort if encountered.
# define LIBBASE_BUILTIN_DEBUGTRAP
#endif

/// \macro LIBBASE_ASSUME_ALIGNED
/// Returns a pointer with an assumed alignment.
#if __has_builtin(__builtin_assume_aligned) || defined(__GNUC__)
# define LIBBASE_ASSUME_ALIGNED(p, a) __builtin_assume_aligned(p, a)
#elif defined(LIBBASE_BUILTIN_UNREACHABLE)
# define LIBBASE_ASSUME_ALIGNED(p, a) \
           (((uintptr_t(p) % (a)) == 0) ? (p) : (LIBBASE_BUILTIN_UNREACHABLE, (p)))
#else
# define LIBBASE_ASSUME_ALIGNED(p, a) (p)
#endif

/// \macro LIBBASE_PACKED
/// Used to specify a packed structure.
/// LIBBASE_PACKED(
///    struct A {
///      int i;
///      int j;
///      int k;
///      long long l;
///   });
///
/// LIBBASE_PACKED_START
/// struct B {
///   int i;
///   int j;
///   int k;
///   long long l;
/// };
/// LIBBASE_PACKED_END
#ifdef _MSC_VER
# define LIBBASE_PACKED(d) __pragma(pack(push, 1)) d __pragma(pack(pop))
# define LIBBASE_PACKED_START __pragma(pack(push, 1))
# define LIBBASE_PACKED_END   __pragma(pack(pop))
#else
# define LIBBASE_PACKED(d) d __attribute__((packed))
# define LIBBASE_PACKED_START _Pragma("pack(push, 1)")
# define LIBBASE_PACKED_END   _Pragma("pack(pop)")
#endif

/// \macro LIBBASE_MEMORY_SANITIZER_BUILD
/// Whether LLVM itself is built with MemorySanitizer instrumentation.
#if __has_feature(memory_sanitizer)
# define LIBBASE_MEMORY_SANITIZER_BUILD 1
# include <sanitizer/msan_interface.h>
# define LIBBASE_NO_SANITIZE_MEMORY_ATTRIBUTE __attribute__((no_sanitize_memory))
#else
# define LIBBASE_MEMORY_SANITIZER_BUILD 0
# define __msan_allocated_memory(p, size)
# define __msan_unpoison(p, size)
# define LIBBASE_NO_SANITIZE_MEMORY_ATTRIBUTE
#endif

/// \macro LIBBASE_ADDRESS_SANITIZER_BUILD
/// Whether LLVM itself is built with AddressSanitizer instrumentation.
#if __has_feature(address_sanitizer) || defined(__SANITIZE_ADDRESS__)
# define LIBBASE_ADDRESS_SANITIZER_BUILD 1
#if __has_include(<sanitizer/asan_interface.h>)
# include <sanitizer/asan_interface.h>
#else
// These declarations exist to support ASan with MSVC. If MSVC eventually ships
// asan_interface.h in their headers, then we can remove this.
#ifdef __cplusplus
extern "C" {
#endif
void __asan_poison_memory_region(void const volatile *addr, size_t size);
void __asan_unpoison_memory_region(void const volatile *addr, size_t size);
#ifdef __cplusplus
} // extern "C"
#endif
#endif
#else
# define LIBBASE_ADDRESS_SANITIZER_BUILD 0
# define __asan_poison_memory_region(p, size)
# define __asan_unpoison_memory_region(p, size)
#endif

/// \macro LIBBASE_HWADDRESS_SANITIZER_BUILD
/// Whether LLVM itself is built with HWAddressSanitizer instrumentation.
#if __has_feature(hwaddress_sanitizer)
#define LIBBASE_HWADDRESS_SANITIZER_BUILD 1
#else
#define LIBBASE_HWADDRESS_SANITIZER_BUILD 0
#endif

/// \macro LIBBASE_THREAD_SANITIZER_BUILD
/// Whether LLVM itself is built with ThreadSanitizer instrumentation.
#if __has_feature(thread_sanitizer) || defined(__SANITIZE_THREAD__)
# define LIBBASE_THREAD_SANITIZER_BUILD 1
#else
# define LIBBASE_THREAD_SANITIZER_BUILD 0
#endif

#if LIBBASE_THREAD_SANITIZER_BUILD
// Thread Sanitizer is a tool that finds races in code.
// See http://code.google.com/p/data-race-test/wiki/DynamicAnnotations .
// tsan detects these exact functions by name.
#ifdef __cplusplus
extern "C" {
#endif
void AnnotateHappensAfter(const char *file, int line, const volatile void *cv);
void AnnotateHappensBefore(const char *file, int line, const volatile void *cv);
void AnnotateIgnoreWritesBegin(const char *file, int line);
void AnnotateIgnoreWritesEnd(const char *file, int line);
#ifdef __cplusplus
}
#endif

// This marker is used to define a happens-before arc. The race detector will
// infer an arc from the begin to the end when they share the same pointer
// argument.
# define TsanHappensBefore(cv) AnnotateHappensBefore(__FILE__, __LINE__, cv)

// This marker defines the destination of a happens-before arc.
# define TsanHappensAfter(cv) AnnotateHappensAfter(__FILE__, __LINE__, cv)

// Ignore any races on writes between here and the next TsanIgnoreWritesEnd.
# define TsanIgnoreWritesBegin() AnnotateIgnoreWritesBegin(__FILE__, __LINE__)

// Resume checking for racy writes.
# define TsanIgnoreWritesEnd() AnnotateIgnoreWritesEnd(__FILE__, __LINE__)
#else
# define TsanHappensBefore(cv)
# define TsanHappensAfter(cv)
# define TsanIgnoreWritesBegin()
# define TsanIgnoreWritesEnd()
#endif

/// \macro LIBBASE_NO_SANITIZE
/// Disable a particular sanitizer for a function.
#if __has_attribute(no_sanitize)
#define LIBBASE_NO_SANITIZE(KIND) __attribute__((no_sanitize(KIND)))
#else
#define LIBBASE_NO_SANITIZE(KIND)
#endif

/// Mark debug helper function definitions like dump() that should not be
/// stripped from debug builds.
/// Note that you should also surround dump() functions with
/// `#if !defined(NDEBUG) || defined(LIBBASE_ENABLE_DUMP)` so they do always
/// get stripped in release builds.
// FIXME: Move this to a private config.h as it's not usable in public headers.
#if !defined(NDEBUG) || defined(LIBBASE_ENABLE_DUMP)
#define LIBBASE_DUMP_METHOD                                                       \
  LIBBASE_ATTRIBUTE_NOINLINE LIBBASE_ATTRIBUTE_USED LIBBASE_ATTRIBUTE_RETAIN
#else
#define LIBBASE_DUMP_METHOD LIBBASE_ATTRIBUTE_NOINLINE
#endif

/// \macro LIBBASE_PRETTY_FUNCTION
/// Gets a user-friendly looking function signature for the current scope
/// using the best available method on each platform.  The exact format of the
/// resulting string is implementation specific and non-portable, so this should
/// only be used, for example, for logging or diagnostics.
#if defined(_MSC_VER)
#define LIBBASE_PRETTY_FUNCTION __FUNCSIG__
#elif defined(__GNUC__) || defined(__clang__)
#define LIBBASE_PRETTY_FUNCTION __PRETTY_FUNCTION__
#else
#define LIBBASE_PRETTY_FUNCTION __func__
#endif

/// \macro LIBBASE_THREAD_LOCAL
/// A thread-local storage specifier which can be used with globals,
/// extern globals, and static globals.
///
/// This is essentially an extremely restricted analog to C++11's thread_local
/// support. It uses thread_local if available, falling back on gcc __thread
/// if not. __thread doesn't support many of the C++11 thread_local's
/// features. You should only use this for PODs that you can statically
/// initialize to some constant value. In almost all circumstances this is most
/// appropriate for use with a pointer, integer, or small aggregation of
/// pointers and integers.
#if LIBBASE_ENABLE_THREADS
#if __has_feature(cxx_thread_local) || defined(_MSC_VER)
#define LIBBASE_THREAD_LOCAL thread_local
#else
// Clang, GCC, and other compatible compilers used __thread prior to C++11 and
// we only need the restricted functionality that provides.
#define LIBBASE_THREAD_LOCAL __thread
#endif
#else // !LIBBASE_ENABLE_THREADS
// If threading is disabled entirely, this compiles to nothing and you get
// a normal global variable.
#define LIBBASE_THREAD_LOCAL
#endif

/// \macro LIBBASE_ENABLE_EXCEPTIONS
/// Whether LLVM is built with exception support.
#if __has_feature(cxx_exceptions)
#define LIBBASE_ENABLE_EXCEPTIONS 1
#elif defined(__GNUC__) && defined(__EXCEPTIONS)
#define LIBBASE_ENABLE_EXCEPTIONS 1
#elif defined(_MSC_VER) && defined(_CPPUNWIND)
#define LIBBASE_ENABLE_EXCEPTIONS 1
#endif

/// \macro LIBBASE_NO_PROFILE_INSTRUMENT_FUNCTION
/// Disable the profile instrument for a function.
#if __has_attribute(no_profile_instrument_function)
#define LIBBASE_NO_PROFILE_INSTRUMENT_FUNCTION                                    \
  __attribute__((no_profile_instrument_function))
#else
#define LIBBASE_NO_PROFILE_INSTRUMENT_FUNCTION
#endif

/// \macro LIBBASE_PREFERRED_TYPE
/// Adjust type of bit-field in debug info.
#if __has_attribute(preferred_type)
#define LIBBASE_PREFERRED_TYPE(T) __attribute__((preferred_type(T)))
#else
#define LIBBASE_PREFERRED_TYPE(T)
#endif

#if LIBBASE_HAS_CPP_ATTRIBUTE(clang::ptrauth_vtable_pointer) &&                   \
    (defined(__PTRAUTH__) || __has_feature(ptrauth_calls))
#define LIBBASE_MOVABLE_POLYMORPHIC_TYPE                                          \
  [[clang::ptrauth_vtable_pointer(default_key, no_address_discrimination,      \
                                  default_extra_discrimination)]]
#else
#define LIBBASE_MOVABLE_POLYMORPHIC_TYPE
#endif

/// \macro LIBBASE_VIRTUAL_ANCHOR_FUNCTION
/// This macro is used to adhere to LLVM's policy that each class with a vtable
/// must have at least one out-of-line virtual function. This macro allows us
/// to declare such a function in `final` classes without triggering a warning.
// clang-format off
// Autoformatting makes this look awful.
#if defined(__clang__)
  // Make sure this is only parsed if __clang__ is defined
  #if __has_warning("-Wunnecessary-virtual-specifier")
    #define LIBBASE_DECLARE_VIRTUAL_ANCHOR_FUNCTION()                            \
      _Pragma("clang diagnostic push")                                        \
      _Pragma("clang diagnostic ignored \"-Wunnecessary-virtual-specifier\"") \
      virtual void anchor()                                                   \
      _Pragma("clang diagnostic pop")
  #else // __has_warning
    #define LIBBASE_DECLARE_VIRTUAL_ANCHOR_FUNCTION()                            \
      virtual void anchor()
  #endif
#else // defined(__clang__)
  #define LIBBASE_DECLARE_VIRTUAL_ANCHOR_FUNCTION()                              \
    virtual void anchor()
#endif
// clang-format on

/// \macro LIBBASE_IS_X86
/// Whether the target architecture is x86 / x86-64.
#if defined(__x86_64__) || defined(__i386__)
#define LIBBASE_IS_X86 1
#else
#define LIBBASE_IS_X86 0
#endif

/// \macro LIBBASE_TARGET_SSE42
/// Function attribute to compile a function with SSE4.2 enabled.
#if defined(__has_attribute) && __has_attribute(target)
#define LIBBASE_TARGET_SSE42 __attribute__((target("sse4.2")))
#else
#define LIBBASE_TARGET_SSE42
#endif

#if __has_builtin(__builtin_cpu_supports) &&                                   \
    (defined(__linux__) || defined(__APPLE__))
#define LIBBASE_CPU_SUPPORTS(feature) __builtin_cpu_supports(feature)
#else
#define LIBBASE_CPU_SUPPORTS(feature) 0
#endif

/// \macro LIBBASE_CPU_SUPPORTS_SSE42
/// Expands to true if the runtime cpu supports SSE4.2, or if compiled with
/// SSE4.2 enabled.
#if defined(__SSE4_2__)
#define LIBBASE_CPU_SUPPORTS_SSE42 1
#else
#define LIBBASE_CPU_SUPPORTS_SSE42 LIBBASE_CPU_SUPPORTS("sse4.2")
#endif

#endif