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/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
/* compile-time and runtime tests for whether to use LoongArch LSX/LASX
* extensions. Adapted from js/src/jit/loong64/Architecture-loong64.cpp. */
#include "LSX.h"
#include "mozilla/Attributes.h"
#include <cstdint>
#include <optional>
#if defined(MOZILLA_LSX_HAVE_HWCAP_DETECTION)
# include <asm/hwcap.h>
# include <sys/auxv.h>
// the toolchain doesn't yet know about them.
enum LoongArchHwCap : uint64_t {
LOONG64_HWCAP_LSX = (UINT64_C(1) << 4),
LOONG64_HWCAP_LASX = (UINT64_C(1) << 5),
};
// Assert the hardcoded feature bits match HWCAP_LOONGARCH_*.
# ifdef HWCAP_LOONGARCH_LSX
static_assert(HWCAP_LOONGARCH_LSX == LOONG64_HWCAP_LSX);
# endif
# ifdef HWCAP_LOONGARCH_LASX
static_assert(HWCAP_LOONGARCH_LASX == LOONG64_HWCAP_LASX);
# endif
struct LoongArchCPUFlags {
bool lsx = false;
bool lasx = false;
};
[[maybe_unused]]
static LoongArchCPUFlags get_loongarch_cpu_flags() {
// This could be expensive, so cache the result.
static std::optional<LoongArchCPUFlags> cpu_flags = std::nullopt;
if (cpu_flags) { // already checked
return *cpu_flags;
}
LoongArchCPUFlags new_flags;
const uint64_t hwcap = getauxval(AT_HWCAP);
if (hwcap & LOONG64_HWCAP_LSX) {
new_flags.lsx = true;
}
if (hwcap & LOONG64_HWCAP_LASX) {
new_flags.lasx = true;
}
cpu_flags = new_flags;
return new_flags;
}
#endif
namespace mozilla {
namespace lsx_private {
#if defined(MOZILLA_LSX_HAVE_HWCAP_DETECTION)
# if !defined(MOZILLA_PRESUME_LSX)
MOZ_RUNINIT bool lsx_enabled = get_loongarch_cpu_flags().lsx;
# endif
# if !defined(MOZILLA_PRESUME_LASX)
MOZ_RUNINIT bool lasx_enabled = get_loongarch_cpu_flags().lasx;
# endif
#endif
} // namespace lsx_private
} // namespace mozilla