ClickHouse/src/Functions/TargetSpecific.h
2021-04-12 23:02:16 +03:00

214 lines
6.9 KiB
C++

#pragma once
#include <common/types.h>
/* This file contains macros and helpers for writing platform-dependent code.
*
* Macros DECLARE_<Arch>_SPECIFIC_CODE will wrap code inside it into the
* namespace TargetSpecific::<Arch> and enable Arch-specific compile options.
* Thus, it's allowed to call functions inside these namespaces only after
* checking platform in runtime (see isArchSupported() below).
*
* If compiler is not gcc/clang or target isn't x86_64 or ENABLE_MULTITARGET_CODE
* was set to OFF in cmake, all code inside these macros will be removed and
* USE_MULTITARGET_CODE will be set to 0. Use #if USE_MULTITARGET_CODE whenever you
* use anything from this namespaces.
*
* For similarities there is a macros DECLARE_DEFAULT_CODE, which wraps code
* into the namespace TargetSpecific::Default but doesn't specify any additional
* copile options. Functions and classes inside this macros are available regardless
* of USE_MUTLITARGE_CODE.
*
* Example of usage:
*
* DECLARE_DEFAULT_CODE (
* int funcImpl() {
* return 1;
* }
* ) // DECLARE_DEFAULT_CODE
*
* DECLARE_AVX2_SPECIFIC_CODE (
* int funcImpl() {
* return 2;
* }
* ) // DECLARE_DEFAULT_CODE
*
* int func() {
* #if USE_MULTITARGET_CODE
* if (isArchSupported(TargetArch::AVX2))
* return TargetSpecific::AVX2::funcImpl();
* #endif
* return TargetSpecific::Default::funcImpl();
* }
*
* Sometimes code may benefit from compiling with different options.
* For these purposes use DECLARE_MULTITARGET_CODE macros. It will create a copy
* of the code for every supported target and compile it with different options.
* These copies are available via TargetSpecific namespaces described above.
*
* Inside every TargetSpecific namespace there is a constexpr variable BuildArch,
* which indicates the target platform for current code.
*
* Example:
*
* DECLARE_MULTITARGET_CODE(
* int funcImpl(int size, ...) {
* int iteration_size = 1;
* if constexpr (BuildArch == TargetArch::SSE42)
* iteration_size = 2
* else if constexpr (BuildArch == TargetArch::AVX || BuildArch == TargetArch::AVX2)
* iteration_size = 4;
* for (int i = 0; i < size; i += iteration_size)
* ...
* }
* ) // DECLARE_MULTITARGET_CODE
*
* // All target-specific and default implementations are available here via
* TargetSpecific::<Arch>::funcImpl. Use runtime detection to choose one.
*
* If you want to write IFunction or IExecutableFuncionImpl with several implementations
* see PerformanceAdaptors.h.
*/
namespace DB
{
enum class TargetArch : UInt32
{
Default = 0, /// Without any additional compiler options.
SSE42 = (1 << 0), /// SSE4.2
AVX = (1 << 1),
AVX2 = (1 << 2),
AVX512F = (1 << 3),
};
/// Runtime detection.
bool isArchSupported(TargetArch arch);
String toString(TargetArch arch);
#if ENABLE_MULTITARGET_CODE && defined(__GNUC__) && defined(__x86_64__)
#define USE_MULTITARGET_CODE 1
#if defined(__clang__)
# define BEGIN_AVX512F_SPECIFIC_CODE \
_Pragma("clang attribute push(__attribute__((target(\"sse,sse2,sse3,ssse3,sse4,popcnt,avx,avx2,avx512f\"))),apply_to=function)")
# define BEGIN_AVX2_SPECIFIC_CODE \
_Pragma("clang attribute push(__attribute__((target(\"sse,sse2,sse3,ssse3,sse4,popcnt,avx,avx2\"))),apply_to=function)")
# define BEGIN_AVX_SPECIFIC_CODE \
_Pragma("clang attribute push(__attribute__((target(\"sse,sse2,sse3,ssse3,sse4,popcnt,avx\"))),apply_to=function)")
# define BEGIN_SSE42_SPECIFIC_CODE \
_Pragma("clang attribute push(__attribute__((target(\"sse,sse2,sse3,ssse3,sse4,popcnt\"))),apply_to=function)")
# define END_TARGET_SPECIFIC_CODE \
_Pragma("clang attribute pop")
/* Clang shows warning when there aren't any objects to apply pragma.
* To prevent this warning we define this function inside every macros with pragmas.
*/
# define DUMMY_FUNCTION_DEFINITION [[maybe_unused]] void __dummy_function_definition();
#else
# define BEGIN_AVX512F_SPECIFIC_CODE \
_Pragma("GCC push_options") \
_Pragma("GCC target(\"sse,sse2,sse3,ssse3,sse4,popcnt,avx,avx2,avx512f,tune=native\")")
# define BEGIN_AVX2_SPECIFIC_CODE \
_Pragma("GCC push_options") \
_Pragma("GCC target(\"sse,sse2,sse3,ssse3,sse4,popcnt,avx,avx2,tune=native\")")
# define BEGIN_AVX_SPECIFIC_CODE \
_Pragma("GCC push_options") \
_Pragma("GCC target(\"sse,sse2,sse3,ssse3,sse4,popcnt,avx,tune=native\")")
# define BEGIN_SSE42_SPECIFIC_CODE \
_Pragma("GCC push_options") \
_Pragma("GCC target(\"sse,sse2,sse3,ssse3,sse4,popcnt,tune=native\")")
# define END_TARGET_SPECIFIC_CODE \
_Pragma("GCC pop_options")
/* GCC doesn't show such warning, we don't need to define anything.
*/
# define DUMMY_FUNCTION_DEFINITION
#endif
#define DECLARE_SSE42_SPECIFIC_CODE(...) \
BEGIN_SSE42_SPECIFIC_CODE \
namespace TargetSpecific::SSE42 { \
DUMMY_FUNCTION_DEFINITION \
using namespace DB::TargetSpecific::SSE42; \
__VA_ARGS__ \
} \
END_TARGET_SPECIFIC_CODE
#define DECLARE_AVX_SPECIFIC_CODE(...) \
BEGIN_AVX_SPECIFIC_CODE \
namespace TargetSpecific::AVX { \
DUMMY_FUNCTION_DEFINITION \
using namespace DB::TargetSpecific::AVX; \
__VA_ARGS__ \
} \
END_TARGET_SPECIFIC_CODE
#define DECLARE_AVX2_SPECIFIC_CODE(...) \
BEGIN_AVX2_SPECIFIC_CODE \
namespace TargetSpecific::AVX2 { \
DUMMY_FUNCTION_DEFINITION \
using namespace DB::TargetSpecific::AVX2; \
__VA_ARGS__ \
} \
END_TARGET_SPECIFIC_CODE
#define DECLARE_AVX512F_SPECIFIC_CODE(...) \
BEGIN_AVX512F_SPECIFIC_CODE \
namespace TargetSpecific::AVX512F { \
DUMMY_FUNCTION_DEFINITION \
using namespace DB::TargetSpecific::AVX512F; \
__VA_ARGS__ \
} \
END_TARGET_SPECIFIC_CODE
#else
#define USE_MULTITARGET_CODE 0
/* Multitarget code is disabled, just delete target-specific code.
*/
#define DECLARE_SSE42_SPECIFIC_CODE(...)
#define DECLARE_AVX_SPECIFIC_CODE(...)
#define DECLARE_AVX2_SPECIFIC_CODE(...)
#define DECLARE_AVX512F_SPECIFIC_CODE(...)
#endif
#define DECLARE_DEFAULT_CODE(...) \
namespace TargetSpecific::Default { \
using namespace DB::TargetSpecific::Default; \
__VA_ARGS__ \
}
#define DECLARE_MULTITARGET_CODE(...) \
DECLARE_DEFAULT_CODE (__VA_ARGS__) \
DECLARE_SSE42_SPECIFIC_CODE (__VA_ARGS__) \
DECLARE_AVX_SPECIFIC_CODE (__VA_ARGS__) \
DECLARE_AVX2_SPECIFIC_CODE (__VA_ARGS__) \
DECLARE_AVX512F_SPECIFIC_CODE(__VA_ARGS__)
DECLARE_DEFAULT_CODE(
constexpr auto BuildArch = TargetArch::Default;
) // DECLARE_DEFAULT_CODE
DECLARE_SSE42_SPECIFIC_CODE(
constexpr auto BuildArch = TargetArch::SSE42;
) // DECLARE_SSE42_SPECIFIC_CODE
DECLARE_AVX_SPECIFIC_CODE(
constexpr auto BuildArch = TargetArch::AVX;
) // DECLARE_AVX_SPECIFIC_CODE
DECLARE_AVX2_SPECIFIC_CODE(
constexpr auto BuildArch = TargetArch::AVX2;
) // DECLARE_AVX2_SPECIFIC_CODE
DECLARE_AVX512F_SPECIFIC_CODE(
constexpr auto BuildArch = TargetArch::AVX512F;
) // DECLARE_AVX512F_SPECIFIC_CODE
}