src/base/build_config.h

// Copyright 2014 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef V8_BASE_BUILD_CONFIG_H_
#define V8_BASE_BUILD_CONFIG_H_

#include "include/v8config.h"

#if defined(__ARM_ARCH_7A__) || defined(__ARM_ARCH_7R__) || \
    defined(__ARM_ARCH_7__)
#define CAN_USE_ARMV7_INSTRUCTIONS 1
#ifdef __ARM_ARCH_EXT_IDIV__
#define CAN_USE_SUDIV 1
#endif
#ifndef CAN_USE_VFP3_INSTRUCTIONS
#define CAN_USE_VFP3_INSTRUCTIONS 1
#endif
#endif

#if defined(__ARM_ARCH_8A__)
#define CAN_USE_ARMV7_INSTRUCTIONS 1
#define CAN_USE_SUDIV 1
#define CAN_USE_ARMV8_INSTRUCTIONS 1
#ifndef CAN_USE_VFP3_INSTRUCTIONS
#define CAN_USE_VFP3_INSTRUCTIONS 1
#endif
#endif

// pthread_jit_write_protect is only available on arm64 Mac.
#if defined(V8_OS_MACOS) && defined(V8_HOST_ARCH_ARM64)
#define V8_HAS_PTHREAD_JIT_WRITE_PROTECT 1
#else
#define V8_HAS_PTHREAD_JIT_WRITE_PROTECT 0
#endif

#if defined(V8_TARGET_ARCH_IA32) || defined(V8_TARGET_ARCH_X64)
#define V8_TARGET_ARCH_STORES_RETURN_ADDRESS_ON_STACK true
#else
#define V8_TARGET_ARCH_STORES_RETURN_ADDRESS_ON_STACK false
#endif
constexpr int kReturnAddressStackSlotCount =
    V8_TARGET_ARCH_STORES_RETURN_ADDRESS_ON_STACK ? 1 : 0;

// Number of bits to represent the page size for paged spaces.
#if (defined(V8_HOST_ARCH_PPC) || defined(V8_HOST_ARCH_PPC64)) && !defined(_AIX)
// Native PPC linux has large (64KB) physical pages.
// Simulator (and Aix) need to use the same value as x64.
const int kPageSizeBits = 19;
#elif defined(ENABLE_HUGEPAGE)
// When enabling huge pages, adjust V8 page size to take up exactly one huge
// page. This avoids huge-page-internal fragmentation for unused address ranges.
const int kHugePageBits = 21;
const int kHugePageSize = (1U) << kHugePageBits;
const int kPageSizeBits = kHugePageBits;
#else
// Arm64 supports up to 64k OS pages on Linux, however 4k pages are more common
// so we keep the V8 page size at 256k. Nonetheless, we need to make sure we
// don't decrease it further in the future due to reserving 3 OS pages for every
// executable V8 page.
const int kPageSizeBits = 18;
#endif

#endif  // V8_BASE_BUILD_CONFIG_H_