text: // This source file is part of the polarphp.org open source project
  //
  // Copyright (c) 2017 - 2019 polarphp software foundation
  // Copyright (c) 2017 - 2019 zzu_softboy <zzu_softboy@163.com>
  // Licensed under Apache License v2.0 with Runtime Library Exception
  //
  // See https://polarphp.org/LICENSE.txt for license information
  // See https://polarphp.org/CONTRIBUTORS.txt for the list of polarphp project authors
  //
  // Created by polarboy on 2018/10/09.
  
  #ifndef POLARPHP_GLOBAL_COMPILER_FEATURE_H
  #define POLARPHP_GLOBAL_COMPILER_FEATURE_H
  
  #include "polarphp/global/CompilerDetection.h"
  #include <new>
  #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_cpp_attribute
  # define __has_cpp_attribute(x) 0
  #endif
  
  #ifndef __has_builtin
  # define __has_builtin(x) 0
  #endif
  
  /// \macro POLAR_GNUC_PREREQ
  /// Extend the default __GNUC_PREREQ even if glibc's features.h isn't
  /// available.
  #ifndef POLAR_GNUC_PREREQ
  # if defined(__GNUC__) && defined(__GNUC_MINOR__) && defined(__GNUC_PATCHLEVEL__)
  #  define POLAR_GNUC_PREREQ(maj, min, patch) \
     ((__GNUC__ << 20) + (__GNUC_MINOR__ << 10) + __GNUC_PATCHLEVEL__ >= \
     ((maj) << 20) + ((min) << 10) + (patch))
  # elif defined(__GNUC__) && defined(__GNUC_MINOR__)
  #  define POLAR_GNUC_PREREQ(maj, min, patch) \
     ((__GNUC__ << 20) + (__GNUC_MINOR__ << 10) >= ((maj) << 20) + ((min) << 10))
  # else
  #  define POLAR_GNUC_PREREQ(maj, min, patch) 0
  # endif
  #endif
  
  /// \macro POLAR_MSC_PREREQ
  /// Is the compiler MSVC of at least the specified version?
  /// The common \param version values to check for are:
  ///  * 1900: Microsoft Visual Studio 2015 / 14.0
  #ifdef _MSC_VER
  #define POLAR_MSC_PREREQ(version) (_MSC_VER >= (version))
  
  // We require at least MSVC 2015.
  #if !POLAR_MSC_PREREQ(1900)
  #error POLAR requires at least MSVC 2015.
  #endif
  
  #else
  #define POLAR_MSC_PREREQ(version) 0
  #endif
  
  /// Does the compiler support ref-qualifiers for *this?
  ///
  /// Sadly, this is separate from just rvalue reference support because GCC
  /// and MSVC implemented this later than everything else.
  #if __has_feature(cxx_rvalue_references) || POLAR_GNUC_PREREQ(4, 8, 1)
  #define POLAR_HAS_RVALUE_REFERENCE_THIS 1
  #else
  #define POLAR_HAS_RVALUE_REFERENCE_THIS 0
  #endif
  
  /// Expands to '&' if ref-qualifiers for *this are supported.
  ///
  /// This can be used to provide lvalue/rvalue overrides of member functions.
  /// The rvalue override should be guarded by POLAR_HAS_RVALUE_REFERENCE_THIS
  #if POLAR_HAS_RVALUE_REFERENCE_THIS
  #define POLAR_LVALUE_FUNCTION &
  #else
  #define POLAR_LVALUE_FUNCTION
  #endif
  
  /// POLAR_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.
  #if (__has_attribute(visibility) || POLAR_GNUC_PREREQ(4, 0, 0)) &&              \
     !defined(__MINGW32__) && !defined(__CYGWIN__) && !defined(_WIN32)
  #define POLAR_LIBRARY_VISIBILITY __attribute__ ((visibility("hidden")))
  #else
  #define POLAR_LIBRARY_VISIBILITY
  #endif
  
  #if defined(__GNUC__)
  #define POLAR_PREFETCH(addr, rw, locality) __builtin_prefetch(addr, rw, locality)
  #else
  #define POLAR_PREFETCH(addr, rw, locality)
  #endif
  
  #if __has_attribute(used) || POLAR_GNUC_PREREQ(3, 1, 0)
  #define POLAR_ATTRIBUTE_USED __attribute__((__used__))
  #else
  #define POLAR_ATTRIBUTE_USED
  #endif
  
  /// POLAR_NODISCARD - Warn if a type or return value is discarded.
  #if __cplusplus > 201402L && __has_cpp_attribute(nodiscard)
  #define POLAR_NODISCARD [[nodiscard]]
  #elif !__cplusplus
  // Workaround for llvm.org/PR23435, since clang 3.6 and below emit a spurious
  // error when __has_cpp_attribute is given a scoped attribute in C mode.
  #define POLAR_NODISCARD
  #elif __has_cpp_attribute(clang::warn_unused_result)
  #define POLAR_NODISCARD [[clang::warn_unused_result]]
  #else
  #define POLAR_NODISCARD
  #endif
  
  
  // 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 __has_cpp_attribute(clang::reinitializes)
  #define POLAR_ATTRIBUTE_REINITIALIZES [[clang::reinitializes]]
  #else
  #define POLAR_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) || POLAR_GNUC_PREREQ(3, 1, 0)
  #define POLAR_ATTRIBUTE_UNUSED __attribute__((__unused__))
  #else
  #define POLAR_ATTRIBUTE_UNUSED
  #endif
  
  // FIXME: Provide this for PE/COFF targets.
  #if (__has_attribute(weak) || POLAR_GNUC_PREREQ(4, 0, 0)) &&                    \
     (!defined(__MINGW32__) && !defined(__CYGWIN__) && !defined(_WIN32))
  #define POLAR_ATTRIBUTE_WEAK __attribute__((__weak__))
  #else
  #define POLAR_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 POLAR Conventions.
  #define POLAR_READNONE __attribute__((__const__))
  #else
  #define POLAR_READNONE
  #endif
  
  #if __has_attribute(pure) || defined(__GNUC__)
  // aka 'PURE' but following POLAR Conventions.
  #define POLAR_READONLY __attribute__((__pure__))
  #else
  #define POLAR_READONLY
  #endif
  
  /// POLAR_ATTRIBUTE_NOINLINE - On compilers where we have a directive to do so,
  /// mark a method "not for inlining".
  #if __has_attribute(noinline) || POLAR_GNUC_PREREQ(3, 4, 0)
  #define POLAR_ATTRIBUTE_NOINLINE __attribute__((noinline))
  #elif defined(_MSC_VER)
  #define POLAR_ATTRIBUTE_NOINLINE __declspec(noinline)
  #else
  #define POLAR_ATTRIBUTE_NOINLINE
  #endif
  
  /// POLAR_ATTRIBUTE_ALWAYS_INLINE - On compilers where we have a directive to do
  /// so, mark a method "always inline" because it is performance sensitive. GCC
  /// 3.4 supported this but is buggy in various cases and produces unimplemented
  /// errors, just use it in GCC 4.0 and later.
  #if __has_attribute(always_inline) || POLAR_GNUC_PREREQ(4, 0, 0)
  #define POLAR_ATTRIBUTE_ALWAYS_INLINE __attribute__((always_inline))
  #elif defined(_MSC_VER)
  #define POLAR_ATTRIBUTE_ALWAYS_INLINE __forceinline
  #else
  #define POLAR_ATTRIBUTE_ALWAYS_INLINE
  #endif
  
  #ifdef __GNUC__
  #define POLAR_ATTRIBUTE_NORETURN __attribute__((noreturn))
  #elif defined(_MSC_VER)
  #define POLAR_ATTRIBUTE_NORETURN __declspec(noreturn)
  #else
  #define POLAR_ATTRIBUTE_NORETURN
  #endif
  
  #if __has_attribute(returns_nonnull) || POLAR_GNUC_PREREQ(4, 9, 0)
  #define POLAR_ATTRIBUTE_RETURNS_NONNULL __attribute__((returns_nonnull))
  #elif defined(_MSC_VER)
  #define POLAR_ATTRIBUTE_RETURNS_NONNULL _Ret_notnull_
  #else
  #define POLAR_ATTRIBUTE_RETURNS_NONNULL
  #endif
  
  /// \macro POLAR_ATTRIBUTE_RETURNS_NOALIAS Used to mark a function as returning a
  /// pointer that does not alias any other valid pointer.
  #ifdef __GNUC__
  #define POLAR_ATTRIBUTE_RETURNS_NOALIAS __attribute__((__malloc__))
  #elif defined(_MSC_VER)
  #define POLAR_ATTRIBUTE_RETURNS_NOALIAS __declspec(restrict)
  #else
  #define POLAR_ATTRIBUTE_RETURNS_NOALIAS
  #endif
  
  /// POLAR_EXTENSION - Support compilers where we have a keyword to suppress
  /// pedantic diagnostics.
  #ifdef __GNUC__
  #define POLAR_EXTENSION __extension__
  #else
  #define POLAR_EXTENSION
  #endif
  
  // POLAR_ATTRIBUTE_DEPRECATED(decl, "message")
  #if __has_feature(attribute_deprecated_with_message)
  # define POLAR_ATTRIBUTE_DEPRECATED(decl, message) \
     decl __attribute__((deprecated(message)))
  #elif defined(__GNUC__)
  # define POLAR_ATTRIBUTE_DEPRECATED(decl, message) \
     decl __attribute__((deprecated))
  #elif defined(_MSC_VER)
  # define POLAR_ATTRIBUTE_DEPRECATED(decl, message) \
     __declspec(deprecated(message)) decl
  #else
  # define POLAR_ATTRIBUTE_DEPRECATED(decl, message) \
     decl
  #endif
  
  /// POLAR_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.
  #if __has_builtin(__builtin_unreachable) || POLAR_GNUC_PREREQ(4, 5, 0)
  # define POLAR_BUILTIN_UNREACHABLE __builtin_unreachable()
  #elif defined(_MSC_VER)
  # define POLAR_BUILTIN_UNREACHABLE __assume(false)
  #endif
  
  /// POLAR_BUILTIN_TRAP - On compilers which support it, expands to an expression
  /// which causes the program to exit abnormally.
  #if __has_builtin(__builtin_trap) || POLAR_GNUC_PREREQ(4, 3, 0)
  # define POLAR_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 POLAR_BUILTIN_TRAP __debugbreak()
  #else
  # define POLAR_BUILTIN_TRAP *(volatile int*)0x11 = 0
  #endif
  
  /// POLAR_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 POLAR_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 POLAR_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 POLAR_BUILTIN_DEBUGTRAP
  #endif
  
  /// \macro POLAR_ASSUME_ALIGNED
  /// Returns a pointer with an assumed alignment.
  #if __has_builtin(__builtin_assume_aligned) || POLAR_GNUC_PREREQ(4, 7, 0)
  # define POLAR_ASSUME_ALIGNED(p, a) __builtin_assume_aligned(p, a)
  #elif defined(POLAR_BUILTIN_UNREACHABLE)
  // As of today, clang does not support __builtin_assume_aligned.
  # define POLAR_ASSUME_ALIGNED(p, a) \
     (((uintptr_t(p) % (a)) == 0) ? (p) : (POLAR_BUILTIN_UNREACHABLE, (p)))
  #else
  # define POLAR_ASSUME_ALIGNED(p, a) (p)
  #endif
  
  /// \macro POLAR_ALIGNAS
  /// Used to specify a minimum alignment for a structure or variable.
  #if __GNUC__ && !__has_feature(cxx_alignas) && !POLAR_GNUC_PREREQ(4, 8, 1)
  # define POLAR_ALIGNAS(x) __attribute__((aligned(x)))
  #else
  # define POLAR_ALIGNAS(x) alignas(x)
  #endif
  
  /// \macro POLAR_PTR_SIZE
  /// A constant integer equivalent to the value of sizeof(void*).
  /// Generally used in combination with POLAR_ALIGNAS or when doing computation in
  /// the preprocessor.
  #ifdef __SIZEOF_POINTER__
  # define POLAR_PTR_SIZE __SIZEOF_POINTER__
  #elif defined(_WIN64)
  # define POLAR_PTR_SIZE 8
  #elif defined(_WIN32)
  # define POLAR_PTR_SIZE 4
  #elif defined(_MSC_VER)
  # error "could not determine POLAR_PTR_SIZE as a constant int for MSVC"
  #else
  # define POLAR_PTR_SIZE sizeof(void *)
  #endif
  
  /// \macro POLAR_MEMORY_SANITIZER_BUILD
  /// Whether POLAR itself is built with MemorySanitizer instrumentation.
  #if __has_feature(memory_sanitizer)
  # define POLAR_MEMORY_SANITIZER_BUILD 1
  # include <sanitizer/msan_interface.h>
  #else
  # define POLAR_MEMORY_SANITIZER_BUILD 0
  # define __msan_allocated_memory(p, size)
  # define __msan_unpoison(p, size)
  #endif
  
  /// \macro POLAR_ADDRESS_SANITIZER_BUILD
  /// Whether POLAR itself is built with AddressSanitizer instrumentation.
  #if __has_feature(address_sanitizer) || defined(__SANITIZE_ADDRESS__)
  # define POLAR_ADDRESS_SANITIZER_BUILD 1
  # include <sanitizer/asan_interface.h>
  #else
  # define POLAR_ADDRESS_SANITIZER_BUILD 0
  # define __asan_poison_memory_region(p, size)
  # define __asan_unpoison_memory_region(p, size)
  #endif
  
  /// \macro POLAR_THREAD_SANITIZER_BUILD
  /// Whether POLAR itself is built with ThreadSanitizer instrumentation.
  #if __has_feature(thread_sanitizer) || defined(__SANITIZE_THREAD__)
  # define POLAR_THREAD_SANITIZER_BUILD 1
  #else
  # define POLAR_THREAD_SANITIZER_BUILD 0
  #endif
  
  #if POLAR_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 POLAR_NO_SANITIZE
  /// Disable a particular sanitizer for a function.
  #if __has_attribute(no_sanitize)
  #define POLAR_NO_SANITIZE(KIND) __attribute__((no_sanitize(KIND)))
  #else
  #define POLAR_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(POLAR_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(POLAR_ENABLE_DUMP)
  #define POLAR_DUMP_METHOD POLAR_ATTRIBUTE_NOINLINE POLAR_ATTRIBUTE_USED
  #else
  #define POLAR_DUMP_METHOD POLAR_ATTRIBUTE_NOINLINE
  #endif
  
  /// \macro POLAR_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 POLAR_PRETTY_FUNCTION __FUNCSIG__
  #elif defined(__GNUC__) || defined(__clang__)
  #define POLAR_PRETTY_FUNCTION __PRETTY_FUNCTION__
  #else
  #define POLAR_PRETTY_FUNCTION __func__
  #endif
  
  /// \macro POLAR_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, and uses that when available. However, it falls back on
  /// platform-specific or vendor-provided extensions when necessary. These
  /// extensions don'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 POLAR_ENABLE_THREADS
  #if __has_feature(cxx_thread_local)
  #define POLAR_THREAD_LOCAL thread_local
  #elif defined(_MSC_VER)
  // MSVC supports this with a __declspec.
  #define POLAR_THREAD_LOCAL __declspec(thread)
  #else
  // Clang, GCC, and other compatible compilers used __thread prior to C++11 and
  // we only need the restricted functionality that provides.
  #define POLAR_THREAD_LOCAL __thread
  #endif
  #else // !POLAR_ENABLE_THREADS
  // If threading is disabled entirely, this compiles to nothing and you get
  // a normal global variable.
  #define POLAR_THREAD_LOCAL
  #endif
  
  /// \macro POLAR_ENABLE_EXCEPTIONS
  /// Whether POLAR is built with exception support.
  #if __has_feature(cxx_exceptions)
  #define POLAR_ENABLE_EXCEPTIONS 1
  #elif defined(__GNUC__) && defined(__EXCEPTIONS)
  #define POLAR_ENABLE_EXCEPTIONS 1
  #elif defined(_MSC_VER) && defined(_CPPUNWIND)
  #define POLAR_ENABLE_EXCEPTIONS 1
  #endif
  
  namespace polar {
  
  /// Allocate a buffer of memory with the given size and alignment.
  ///
  /// When the compiler supports aligned operator new, this will use it to to
  /// handle even over-aligned allocations.
  ///
  /// However, this doesn't make any attempt to leverage the fancier techniques
  /// like posix_memalign due to portability. It is mostly intended to allow
  /// compatibility with platforms that, after aligned allocation was added, use
  /// reduced default alignment.
  inline void *allocate_buffer(size_t size, size_t alignment) {
     return ::operator new(size
                        #ifdef __cpp_aligned_new
                           ,
                           std::align_val_t(alignment)
                        #endif
                           );
  }
  
  /// Deallocate a buffer of memory with the given size and alignment.
  ///
  /// If supported, this will used the sized delete operator. Also if supported,
  /// this will pass the alignment to the delete operator.
  ///
  /// The pointer must have been allocated with the corresponding new operator,
  /// most likely using the above helper.
  inline void deallocate_buffer(void *ptr, size_t size, size_t alignment) {
     ::operator delete(ptr
        #ifdef __cpp_sized_deallocation
           ,
           size
        #endif
        #if __cpp_aligned_new
           ,
           std::align_val_t(alignment)
        #endif
           );
  }
  
  } // polar
  
  #ifdef POLAR_CC_GNU
  #define POLAR_BEGIN_DISABLE_ZENDVM_WARNING() \
     POLAR_WARNING_PUSH\
     _Pragma("GCC diagnostic ignored \"-Wignored-qualifiers\"")\
     _Pragma("GCC diagnostic ignored \"-Wpedantic\"")
  
  #define POLAR_END_DISABLE_ZENDVM_WARNING() POLAR_WARNING_POP
  #endif
  
  /// \macro POLAR_PACKED
  /// Used to specify a packed structure.
  /// POLAR_PACKED(
  ///    struct A {
  ///      int i;
  ///      int j;
  ///      int k;
  ///      long long l;
  ///   });
  ///
  /// POLAR_PACKED_START
  /// struct B {
  ///   int i;
  ///   int j;
  ///   int k;
  ///   long long l;
  /// };
  /// POLAR_PACKED_END
  #ifdef _MSC_VER
  # define POLAR_PACKED(d) __pragma(pack(push, 1)) d __pragma(pack(pop))
  # define POLAR_PACKED_START __pragma(pack(push, 1))
  # define POLAR_PACKED_END   __pragma(pack(pop))
  #else
  # define POLAR_PACKED(d) d __attribute__((packed))
  # define POLAR_PACKED_START _Pragma("pack(push, 1)")
  # define POLAR_PACKED_END   _Pragma("pack(pop)")
  #endif
  
  #endif // POLAR_DEVLTOOLS_UTILS_COMPILER_FEATURE_H
  