ClickHouse/base/common/defines.h

#pragma once

/// __has_feature supported only by clang.
///
/// But libcxx/libcxxabi overrides it to 0,
/// thus the checks for __has_feature will be wrong.
///
/// NOTE:
/// - __has_feature cannot be simply undefined,
///   since this will be broken if some C++ header will be included after
///   including <common/defines.h>
/// - it should not have fallback to 0,
///   since this may create false-positive detection (common problem)
#if defined(__clang__) && defined(__has_feature)
#    define ch_has_feature __has_feature
#endif

#if defined(_MSC_VER)
#   if !defined(likely)
#      define likely(x)   (x)
#   endif
#   if !defined(unlikely)
#      define unlikely(x) (x)
#   endif
#else
#   if !defined(likely)
#       define likely(x)   (__builtin_expect(!!(x), 1))
#   endif
#   if !defined(unlikely)
#       define unlikely(x) (__builtin_expect(!!(x), 0))
#   endif
#endif

#if defined(_MSC_VER)
#    define ALWAYS_INLINE __forceinline
#    define NO_INLINE static __declspec(noinline)
#    define MAY_ALIAS
#else
#    define ALWAYS_INLINE __attribute__((__always_inline__))
#    define NO_INLINE __attribute__((__noinline__))
#    define MAY_ALIAS __attribute__((__may_alias__))
#endif

#if !defined(__x86_64__) && !defined(__aarch64__) && !defined(__PPC__)
#    error "The only supported platforms are x86_64 and AArch64, PowerPC (work in progress)"
#endif

/// Check for presence of address sanitizer
#if !defined(ADDRESS_SANITIZER)
#    if defined(ch_has_feature)
#        if ch_has_feature(address_sanitizer)
#            define ADDRESS_SANITIZER 1
#        endif
#    elif defined(__SANITIZE_ADDRESS__)
#        define ADDRESS_SANITIZER 1
#    endif
#endif

#if !defined(THREAD_SANITIZER)
#    if defined(ch_has_feature)
#        if ch_has_feature(thread_sanitizer)
#            define THREAD_SANITIZER 1
#        endif
#    elif defined(__SANITIZE_THREAD__)
#        define THREAD_SANITIZER 1
#    endif
#endif

#if !defined(MEMORY_SANITIZER)
#    if defined(ch_has_feature)
#        if ch_has_feature(memory_sanitizer)
#            define MEMORY_SANITIZER 1
#        endif
#    elif defined(__MEMORY_SANITIZER__)
#        define MEMORY_SANITIZER 1
#    endif
#endif

#if !defined(UNDEFINED_BEHAVIOR_SANITIZER)
#    if defined(__has_feature)
#        if __has_feature(undefined_behavior_sanitizer)
#            define UNDEFINED_BEHAVIOR_SANITIZER 1
#        endif
#    elif defined(__UNDEFINED_BEHAVIOR_SANITIZER__)
#        define UNDEFINED_BEHAVIOR_SANITIZER 1
#    endif
#endif

#if defined(ADDRESS_SANITIZER)
#    define BOOST_USE_ASAN 1
#    define BOOST_USE_UCONTEXT 1
#endif

#if defined(THREAD_SANITIZER)
#    define BOOST_USE_TSAN 1
#    define BOOST_USE_UCONTEXT 1
#endif

#if defined(ARCADIA_BUILD) && defined(BOOST_USE_UCONTEXT)
#    undef BOOST_USE_UCONTEXT
#endif

/// TODO: Strange enough, there is no way to detect UB sanitizer.

/// Explicitly allow undefined behaviour for certain functions. Use it as a function attribute.
/// It is useful in case when compiler cannot see (and exploit) it, but UBSan can.
/// Example: multiplication of signed integers with possibility of overflow when both sides are from user input.
#if defined(__clang__)
#    define NO_SANITIZE_UNDEFINED __attribute__((__no_sanitize__("undefined")))
#    define NO_SANITIZE_ADDRESS __attribute__((__no_sanitize__("address")))
#    define NO_SANITIZE_THREAD __attribute__((__no_sanitize__("thread")))
#    define ALWAYS_INLINE_NO_SANITIZE_UNDEFINED __attribute__((__always_inline__, __no_sanitize__("undefined")))
#else  /// It does not work in GCC. GCC 7 cannot recognize this attribute and GCC 8 simply ignores it.
#    define NO_SANITIZE_UNDEFINED
#    define NO_SANITIZE_ADDRESS
#    define NO_SANITIZE_THREAD
#    define ALWAYS_INLINE_NO_SANITIZE_UNDEFINED ALWAYS_INLINE
#endif

/// A template function for suppressing warnings about unused variables or function results.
template <typename... Args>
constexpr void UNUSED(Args &&... args [[maybe_unused]])
{
}