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|
// Copyright 2012 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.
// Platform-specific code for POSIX goes here. This is not a platform on its
// own, but contains the parts which are the same across the POSIX platforms
// Linux, MacOS, FreeBSD, OpenBSD, NetBSD and QNX.
#include <errno.h>
#include <limits.h>
#include <pthread.h>
#if defined(__DragonFly__) || defined(__FreeBSD__) || defined(__OpenBSD__)
#include <pthread_np.h> // for pthread_set_name_np
#endif
#include <sched.h> // for sched_yield
#include <stdio.h>
#include <time.h>
#include <unistd.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <sys/time.h>
#include <sys/types.h>
#if defined(__APPLE__) || defined(__DragonFly__) || defined(__FreeBSD__) || \
defined(__NetBSD__) || defined(__OpenBSD__)
#include <sys/sysctl.h> // NOLINT, for sysctl
#endif
#if defined(ANDROID) && !defined(V8_ANDROID_LOG_STDOUT)
#define LOG_TAG "v8"
#include <android/log.h> // NOLINT
#endif
#include <cmath>
#include <cstdlib>
#include "src/base/platform/platform-posix.h"
#include "src/base/lazy-instance.h"
#include "src/base/macros.h"
#include "src/base/platform/platform.h"
#include "src/base/platform/time.h"
#include "src/base/utils/random-number-generator.h"
#ifdef V8_FAST_TLS_SUPPORTED
#include "src/base/atomicops.h"
#endif
#if V8_OS_MACOSX
#include <dlfcn.h>
#endif
#if V8_OS_LINUX
#include <sys/prctl.h> // NOLINT, for prctl
#endif
#if defined(V8_OS_FUCHSIA)
#include <zircon/process.h>
#else
#include <sys/resource.h>
#endif
#if !defined(_AIX) && !defined(V8_OS_FUCHSIA)
#include <sys/syscall.h>
#endif
#if V8_OS_FREEBSD || V8_OS_MACOSX || V8_OS_OPENBSD || V8_OS_SOLARIS
#define MAP_ANONYMOUS MAP_ANON
#endif
#if defined(V8_OS_SOLARIS)
#if (defined(_POSIX_C_SOURCE) && _POSIX_C_SOURCE > 2) || defined(__EXTENSIONS__)
extern "C" int madvise(caddr_t, size_t, int);
#else
extern int madvise(caddr_t, size_t, int);
#endif
#endif
#ifndef MADV_FREE
#define MADV_FREE MADV_DONTNEED
#endif
namespace v8 {
namespace base {
namespace {
// 0 is never a valid thread id.
const pthread_t kNoThread = (pthread_t) 0;
bool g_hard_abort = false;
const char* g_gc_fake_mmap = nullptr;
static LazyInstance<RandomNumberGenerator>::type
platform_random_number_generator = LAZY_INSTANCE_INITIALIZER;
static LazyMutex rng_mutex = LAZY_MUTEX_INITIALIZER;
#if !V8_OS_FUCHSIA
#if V8_OS_MACOSX
// kMmapFd is used to pass vm_alloc flags to tag the region with the user
// defined tag 255 This helps identify V8-allocated regions in memory analysis
// tools like vmmap(1).
const int kMmapFd = VM_MAKE_TAG(255);
#else // !V8_OS_MACOSX
const int kMmapFd = -1;
#endif // !V8_OS_MACOSX
const int kMmapFdOffset = 0;
int GetProtectionFromMemoryPermission(OS::MemoryPermission access) {
switch (access) {
case OS::MemoryPermission::kNoAccess:
return PROT_NONE;
case OS::MemoryPermission::kRead:
return PROT_READ;
case OS::MemoryPermission::kReadWrite:
return PROT_READ | PROT_WRITE;
case OS::MemoryPermission::kReadWriteExecute:
return PROT_READ | PROT_WRITE | PROT_EXEC;
case OS::MemoryPermission::kReadExecute:
return PROT_READ | PROT_EXEC;
}
UNREACHABLE();
}
int GetFlagsForMemoryPermission(OS::MemoryPermission access) {
int flags = MAP_PRIVATE | MAP_ANONYMOUS;
if (access == OS::MemoryPermission::kNoAccess) {
#if !V8_OS_AIX && !V8_OS_FREEBSD && !V8_OS_QNX
flags |= MAP_NORESERVE;
#endif // !V8_OS_AIX && !V8_OS_FREEBSD && !V8_OS_QNX
#if V8_OS_QNX
flags |= MAP_LAZY;
#endif // V8_OS_QNX
}
return flags;
}
void* Allocate(void* address, size_t size, OS::MemoryPermission access) {
int prot = GetProtectionFromMemoryPermission(access);
int flags = GetFlagsForMemoryPermission(access);
void* result = mmap(address, size, prot, flags, kMmapFd, kMmapFdOffset);
if (result == MAP_FAILED) return nullptr;
return result;
}
int ReclaimInaccessibleMemory(void* address, size_t size) {
#if defined(OS_MACOSX)
// On OSX, MADV_FREE_REUSABLE has comparable behavior to MADV_FREE, but also
// marks the pages with the reusable bit, which allows both Activity Monitor
// and memory-infra to correctly track the pages.
int ret = madvise(address, size, MADV_FREE_REUSABLE);
#elif defined(_AIX) || defined(V8_OS_SOLARIS)
int ret = madvise(reinterpret_cast<caddr_t>(address), size, MADV_FREE);
#else
int ret = madvise(address, size, MADV_FREE);
#endif
if (ret != 0 && errno == ENOSYS)
return 0; // madvise is not available on all systems.
if (ret != 0 && errno == EINVAL) {
// MADV_FREE only works on Linux 4.5+ . If request failed, retry with older
// MADV_DONTNEED . Note that MADV_FREE being defined at compile time doesn't
// imply runtime support.
#if defined(_AIX) || defined(V8_OS_SOLARIS)
ret = madvise(reinterpret_cast<caddr_t>(address), size, MADV_DONTNEED);
#else
ret = madvise(address, size, MADV_DONTNEED);
#endif
}
return ret;
}
#endif // !V8_OS_FUCHSIA
} // namespace
void OS::Initialize(bool hard_abort, const char* const gc_fake_mmap) {
g_hard_abort = hard_abort;
g_gc_fake_mmap = gc_fake_mmap;
}
int OS::ActivationFrameAlignment() {
#if V8_TARGET_ARCH_ARM
// On EABI ARM targets this is required for fp correctness in the
// runtime system.
return 8;
#elif V8_TARGET_ARCH_MIPS
return 8;
#elif V8_TARGET_ARCH_S390
return 8;
#else
// Otherwise we just assume 16 byte alignment, i.e.:
// - With gcc 4.4 the tree vectorization optimizer can generate code
// that requires 16 byte alignment such as movdqa on x86.
// - Mac OS X, PPC and Solaris (64-bit) activation frames must
// be 16 byte-aligned; see "Mac OS X ABI Function Call Guide"
return 16;
#endif
}
// static
size_t OS::AllocatePageSize() {
return static_cast<size_t>(sysconf(_SC_PAGESIZE));
}
// static
size_t OS::CommitPageSize() {
static size_t page_size = getpagesize();
return page_size;
}
// static
void OS::SetRandomMmapSeed(int64_t seed) {
if (seed) {
LockGuard<Mutex> guard(rng_mutex.Pointer());
platform_random_number_generator.Pointer()->SetSeed(seed);
}
}
// static
void* OS::GetRandomMmapAddr() {
uintptr_t raw_addr;
{
LockGuard<Mutex> guard(rng_mutex.Pointer());
platform_random_number_generator.Pointer()->NextBytes(&raw_addr,
sizeof(raw_addr));
}
#if defined(V8_USE_ADDRESS_SANITIZER) || defined(MEMORY_SANITIZER) || \
defined(THREAD_SANITIZER) || defined(LEAK_SANITIZER)
// If random hint addresses interfere with address ranges hard coded in
// sanitizers, bad things happen. This address range is copied from TSAN
// source but works with all tools.
// See crbug.com/539863.
raw_addr &= 0x007fffff0000ULL;
raw_addr += 0x7e8000000000ULL;
#else
#if V8_TARGET_ARCH_X64
// Currently available CPUs have 48 bits of virtual addressing. Truncate
// the hint address to 46 bits to give the kernel a fighting chance of
// fulfilling our placement request.
raw_addr &= uint64_t{0x3FFFFFFFF000};
#elif V8_TARGET_ARCH_PPC64
#if V8_OS_AIX
// AIX: 64 bits of virtual addressing, but we limit address range to:
// a) minimize Segment Lookaside Buffer (SLB) misses and
raw_addr &= uint64_t{0x3FFFF000};
// Use extra address space to isolate the mmap regions.
raw_addr += uint64_t{0x400000000000};
#elif V8_TARGET_BIG_ENDIAN
// Big-endian Linux: 44 bits of virtual addressing.
raw_addr &= uint64_t{0x03FFFFFFF000};
#else
// Little-endian Linux: 48 bits of virtual addressing.
raw_addr &= uint64_t{0x3FFFFFFFF000};
#endif
#elif V8_TARGET_ARCH_MIPS64
// We allocate code in 256 MB aligned segments because of optimizations using
// J instruction that require that all code is within a single 256 MB segment
raw_addr &= uint64_t{0x3FFFE0000000};
#elif V8_TARGET_ARCH_S390X
// Linux on Z uses bits 22-32 for Region Indexing, which translates to 42 bits
// of virtual addressing. Truncate to 40 bits to allow kernel chance to
// fulfill request.
raw_addr &= uint64_t{0xFFFFFFF000};
#elif V8_TARGET_ARCH_S390
// 31 bits of virtual addressing. Truncate to 29 bits to allow kernel chance
// to fulfill request.
raw_addr &= 0x1FFFF000;
#else
raw_addr &= 0x3FFFF000;
#ifdef __sun
// For our Solaris/illumos mmap hint, we pick a random address in the bottom
// half of the top half of the address space (that is, the third quarter).
// Because we do not MAP_FIXED, this will be treated only as a hint -- the
// system will not fail to mmap() because something else happens to already
// be mapped at our random address. We deliberately set the hint high enough
// to get well above the system's break (that is, the heap); Solaris and
// illumos will try the hint and if that fails allocate as if there were
// no hint at all. The high hint prevents the break from getting hemmed in
// at low values, ceding half of the address space to the system heap.
raw_addr += 0x80000000;
#elif V8_OS_AIX
// The range 0x30000000 - 0xD0000000 is available on AIX;
// choose the upper range.
raw_addr += 0x90000000;
#else
// The range 0x20000000 - 0x60000000 is relatively unpopulated across a
// variety of ASLR modes (PAE kernel, NX compat mode, etc) and on macos
// 10.6 and 10.7.
raw_addr += 0x20000000;
#endif
#endif
#endif
return reinterpret_cast<void*>(raw_addr);
}
// TODO(bbudge) Move Cygwin and Fuschia stuff into platform-specific files.
#if !V8_OS_CYGWIN && !V8_OS_FUCHSIA
// static
void* OS::Allocate(void* address, size_t size, size_t alignment,
MemoryPermission access) {
size_t page_size = AllocatePageSize();
DCHECK_EQ(0, size % page_size);
DCHECK_EQ(0, alignment % page_size);
address = AlignedAddress(address, alignment);
// Add the maximum misalignment so we are guaranteed an aligned base address.
size_t request_size = size + (alignment - page_size);
request_size = RoundUp(request_size, OS::AllocatePageSize());
void* result = base::Allocate(address, request_size, access);
if (result == nullptr) return nullptr;
// Unmap memory allocated before the aligned base address.
uint8_t* base = static_cast<uint8_t*>(result);
uint8_t* aligned_base = RoundUp(base, alignment);
if (aligned_base != base) {
DCHECK_LT(base, aligned_base);
size_t prefix_size = static_cast<size_t>(aligned_base - base);
CHECK(Free(base, prefix_size));
request_size -= prefix_size;
}
// Unmap memory allocated after the potentially unaligned end.
if (size != request_size) {
DCHECK_LT(size, request_size);
size_t suffix_size = request_size - size;
CHECK(Free(aligned_base + size, suffix_size));
request_size -= suffix_size;
}
DCHECK_EQ(size, request_size);
return static_cast<void*>(aligned_base);
}
// static
bool OS::Free(void* address, const size_t size) {
DCHECK_EQ(0, reinterpret_cast<uintptr_t>(address) % AllocatePageSize());
DCHECK_EQ(0, size % AllocatePageSize());
return munmap(address, size) == 0;
}
// static
bool OS::Release(void* address, size_t size) {
DCHECK_EQ(0, reinterpret_cast<uintptr_t>(address) % CommitPageSize());
DCHECK_EQ(0, size % CommitPageSize());
return munmap(address, size) == 0;
}
// static
bool OS::SetPermissions(void* address, size_t size, MemoryPermission access) {
DCHECK_EQ(0, reinterpret_cast<uintptr_t>(address) % CommitPageSize());
DCHECK_EQ(0, size % CommitPageSize());
int prot = GetProtectionFromMemoryPermission(access);
int ret = mprotect(address, size, prot);
if (ret == 0 && access == OS::MemoryPermission::kNoAccess) {
ret = ReclaimInaccessibleMemory(address, size);
}
// For accounting purposes, we want to call MADV_FREE_REUSE on macOS after
// changing permissions away from OS::MemoryPermission::kNoAccess. Since this
// state is not kept at this layer, we always call this if access != kNoAccess.
// The cost is a syscall that effectively no-ops.
// TODO(erikchen): Fix this to only call MADV_FREE_REUSE when necessary.
// https://crbug.com/823915
#if defined(OS_MACOSX)
if (access != OS::MemoryPermission::kNoAccess)
madvise(address, size, MADV_FREE_REUSE);
#endif
return ret == 0;
}
// static
bool OS::HasLazyCommits() {
#if V8_OS_AIX || V8_OS_LINUX || V8_OS_MACOSX
return true;
#else
// TODO(bbudge) Return true for all POSIX platforms.
return false;
#endif
}
#endif // !V8_OS_CYGWIN && !V8_OS_FUCHSIA
const char* OS::GetGCFakeMMapFile() {
return g_gc_fake_mmap;
}
void OS::Sleep(TimeDelta interval) {
usleep(static_cast<useconds_t>(interval.InMicroseconds()));
}
void OS::Abort() {
if (g_hard_abort) {
V8_IMMEDIATE_CRASH();
}
// Redirect to std abort to signal abnormal program termination.
abort();
}
void OS::DebugBreak() {
#if V8_HOST_ARCH_ARM
asm("bkpt 0");
#elif V8_HOST_ARCH_ARM64
asm("brk 0");
#elif V8_HOST_ARCH_MIPS
asm("break");
#elif V8_HOST_ARCH_MIPS64
asm("break");
#elif V8_HOST_ARCH_PPC
asm("twge 2,2");
#elif V8_HOST_ARCH_IA32
asm("int $3");
#elif V8_HOST_ARCH_X64
asm("int $3");
#elif V8_HOST_ARCH_S390
// Software breakpoint instruction is 0x0001
asm volatile(".word 0x0001");
#else
#error Unsupported host architecture.
#endif
}
class PosixMemoryMappedFile final : public OS::MemoryMappedFile {
public:
PosixMemoryMappedFile(FILE* file, void* memory, size_t size)
: file_(file), memory_(memory), size_(size) {}
~PosixMemoryMappedFile() final;
void* memory() const final { return memory_; }
size_t size() const final { return size_; }
private:
FILE* const file_;
void* const memory_;
size_t const size_;
};
// static
OS::MemoryMappedFile* OS::MemoryMappedFile::open(const char* name) {
if (FILE* file = fopen(name, "r+")) {
if (fseek(file, 0, SEEK_END) == 0) {
long size = ftell(file); // NOLINT(runtime/int)
if (size >= 0) {
void* const memory =
mmap(OS::GetRandomMmapAddr(), size, PROT_READ | PROT_WRITE,
MAP_SHARED, fileno(file), 0);
if (memory != MAP_FAILED) {
return new PosixMemoryMappedFile(file, memory, size);
}
}
}
fclose(file);
}
return nullptr;
}
// static
OS::MemoryMappedFile* OS::MemoryMappedFile::create(const char* name,
size_t size, void* initial) {
if (FILE* file = fopen(name, "w+")) {
size_t result = fwrite(initial, 1, size, file);
if (result == size && !ferror(file)) {
void* memory = mmap(OS::GetRandomMmapAddr(), result,
PROT_READ | PROT_WRITE, MAP_SHARED, fileno(file), 0);
if (memory != MAP_FAILED) {
return new PosixMemoryMappedFile(file, memory, result);
}
}
fclose(file);
}
return nullptr;
}
PosixMemoryMappedFile::~PosixMemoryMappedFile() {
if (memory_) CHECK(OS::Free(memory_, size_));
fclose(file_);
}
int OS::GetCurrentProcessId() {
return static_cast<int>(getpid());
}
int OS::GetCurrentThreadId() {
#if V8_OS_MACOSX || (V8_OS_ANDROID && defined(__APPLE__))
return static_cast<int>(pthread_mach_thread_np(pthread_self()));
#elif V8_OS_LINUX
return static_cast<int>(syscall(__NR_gettid));
#elif V8_OS_ANDROID
return static_cast<int>(gettid());
#elif V8_OS_AIX
return static_cast<int>(thread_self());
#elif V8_OS_FUCHSIA
return static_cast<int>(zx_thread_self());
#elif V8_OS_SOLARIS
return static_cast<int>(pthread_self());
#else
return static_cast<int>(reinterpret_cast<intptr_t>(pthread_self()));
#endif
}
void OS::ExitProcess(int exit_code) {
// Use _exit instead of exit to avoid races between isolate
// threads and static destructors.
fflush(stdout);
fflush(stderr);
_exit(exit_code);
}
// ----------------------------------------------------------------------------
// POSIX date/time support.
//
#if !defined(V8_OS_FUCHSIA)
int OS::GetUserTime(uint32_t* secs, uint32_t* usecs) {
struct rusage usage;
if (getrusage(RUSAGE_SELF, &usage) < 0) return -1;
*secs = static_cast<uint32_t>(usage.ru_utime.tv_sec);
*usecs = static_cast<uint32_t>(usage.ru_utime.tv_usec);
return 0;
}
#endif
double OS::TimeCurrentMillis() {
return Time::Now().ToJsTime();
}
double PosixTimezoneCache::DaylightSavingsOffset(double time) {
if (std::isnan(time)) return std::numeric_limits<double>::quiet_NaN();
time_t tv = static_cast<time_t>(std::floor(time/msPerSecond));
struct tm tm;
struct tm* t = localtime_r(&tv, &tm);
if (nullptr == t) return std::numeric_limits<double>::quiet_NaN();
return t->tm_isdst > 0 ? 3600 * msPerSecond : 0;
}
int OS::GetLastError() {
return errno;
}
// ----------------------------------------------------------------------------
// POSIX stdio support.
//
FILE* OS::FOpen(const char* path, const char* mode) {
FILE* file = fopen(path, mode);
if (file == nullptr) return nullptr;
struct stat file_stat;
if (fstat(fileno(file), &file_stat) != 0) {
fclose(file);
return nullptr;
}
bool is_regular_file = ((file_stat.st_mode & S_IFREG) != 0);
if (is_regular_file) return file;
fclose(file);
return nullptr;
}
bool OS::Remove(const char* path) {
return (remove(path) == 0);
}
char OS::DirectorySeparator() { return '/'; }
bool OS::isDirectorySeparator(const char ch) {
return ch == DirectorySeparator();
}
FILE* OS::OpenTemporaryFile() {
return tmpfile();
}
const char* const OS::LogFileOpenMode = "w";
void OS::Print(const char* format, ...) {
va_list args;
va_start(args, format);
VPrint(format, args);
va_end(args);
}
void OS::VPrint(const char* format, va_list args) {
#if defined(ANDROID) && !defined(V8_ANDROID_LOG_STDOUT)
__android_log_vprint(ANDROID_LOG_INFO, LOG_TAG, format, args);
#else
vprintf(format, args);
#endif
}
void OS::FPrint(FILE* out, const char* format, ...) {
va_list args;
va_start(args, format);
VFPrint(out, format, args);
va_end(args);
}
void OS::VFPrint(FILE* out, const char* format, va_list args) {
#if defined(ANDROID) && !defined(V8_ANDROID_LOG_STDOUT)
__android_log_vprint(ANDROID_LOG_INFO, LOG_TAG, format, args);
#else
vfprintf(out, format, args);
#endif
}
void OS::PrintError(const char* format, ...) {
va_list args;
va_start(args, format);
VPrintError(format, args);
va_end(args);
}
void OS::VPrintError(const char* format, va_list args) {
#if defined(ANDROID) && !defined(V8_ANDROID_LOG_STDOUT)
__android_log_vprint(ANDROID_LOG_ERROR, LOG_TAG, format, args);
#else
vfprintf(stderr, format, args);
#endif
}
int OS::SNPrintF(char* str, int length, const char* format, ...) {
va_list args;
va_start(args, format);
int result = VSNPrintF(str, length, format, args);
va_end(args);
return result;
}
int OS::VSNPrintF(char* str,
int length,
const char* format,
va_list args) {
int n = vsnprintf(str, length, format, args);
if (n < 0 || n >= length) {
// If the length is zero, the assignment fails.
if (length > 0)
str[length - 1] = '\0';
return -1;
} else {
return n;
}
}
// ----------------------------------------------------------------------------
// POSIX string support.
//
char* OS::StrChr(char* str, int c) {
return strchr(str, c);
}
void OS::StrNCpy(char* dest, int length, const char* src, size_t n) {
strncpy(dest, src, n);
}
// ----------------------------------------------------------------------------
// POSIX thread support.
//
class Thread::PlatformData {
public:
PlatformData() : thread_(kNoThread) {}
pthread_t thread_; // Thread handle for pthread.
// Synchronizes thread creation
Mutex thread_creation_mutex_;
};
Thread::Thread(const Options& options)
: data_(new PlatformData),
stack_size_(options.stack_size()),
start_semaphore_(nullptr) {
if (stack_size_ > 0 && static_cast<size_t>(stack_size_) < PTHREAD_STACK_MIN) {
stack_size_ = PTHREAD_STACK_MIN;
}
set_name(options.name());
}
Thread::~Thread() {
delete data_;
}
static void SetThreadName(const char* name) {
#if V8_OS_DRAGONFLYBSD || V8_OS_FREEBSD || V8_OS_OPENBSD
pthread_set_name_np(pthread_self(), name);
#elif V8_OS_NETBSD
STATIC_ASSERT(Thread::kMaxThreadNameLength <= PTHREAD_MAX_NAMELEN_NP);
pthread_setname_np(pthread_self(), "%s", name);
#elif V8_OS_MACOSX
// pthread_setname_np is only available in 10.6 or later, so test
// for it at runtime.
int (*dynamic_pthread_setname_np)(const char*);
*reinterpret_cast<void**>(&dynamic_pthread_setname_np) =
dlsym(RTLD_DEFAULT, "pthread_setname_np");
if (dynamic_pthread_setname_np == nullptr) return;
// Mac OS X does not expose the length limit of the name, so hardcode it.
static const int kMaxNameLength = 63;
STATIC_ASSERT(Thread::kMaxThreadNameLength <= kMaxNameLength);
dynamic_pthread_setname_np(name);
#elif defined(PR_SET_NAME)
prctl(PR_SET_NAME,
reinterpret_cast<unsigned long>(name), // NOLINT
0, 0, 0);
#endif
}
static void* ThreadEntry(void* arg) {
Thread* thread = reinterpret_cast<Thread*>(arg);
// We take the lock here to make sure that pthread_create finished first since
// we don't know which thread will run first (the original thread or the new
// one).
{ LockGuard<Mutex> lock_guard(&thread->data()->thread_creation_mutex_); }
SetThreadName(thread->name());
DCHECK_NE(thread->data()->thread_, kNoThread);
thread->NotifyStartedAndRun();
return nullptr;
}
void Thread::set_name(const char* name) {
strncpy(name_, name, sizeof(name_));
name_[sizeof(name_) - 1] = '\0';
}
void Thread::Start() {
int result;
pthread_attr_t attr;
memset(&attr, 0, sizeof(attr));
result = pthread_attr_init(&attr);
DCHECK_EQ(0, result);
size_t stack_size = stack_size_;
if (stack_size == 0) {
#if V8_OS_MACOSX
// Default on Mac OS X is 512kB -- bump up to 1MB
stack_size = 1 * 1024 * 1024;
#elif V8_OS_AIX
// Default on AIX is 96kB -- bump up to 2MB
stack_size = 2 * 1024 * 1024;
#endif
}
if (stack_size > 0) {
result = pthread_attr_setstacksize(&attr, stack_size);
DCHECK_EQ(0, result);
}
{
LockGuard<Mutex> lock_guard(&data_->thread_creation_mutex_);
result = pthread_create(&data_->thread_, &attr, ThreadEntry, this);
}
DCHECK_EQ(0, result);
result = pthread_attr_destroy(&attr);
DCHECK_EQ(0, result);
DCHECK_NE(data_->thread_, kNoThread);
USE(result);
}
void Thread::Join() { pthread_join(data_->thread_, nullptr); }
static Thread::LocalStorageKey PthreadKeyToLocalKey(pthread_key_t pthread_key) {
#if V8_OS_CYGWIN
// We need to cast pthread_key_t to Thread::LocalStorageKey in two steps
// because pthread_key_t is a pointer type on Cygwin. This will probably not
// work on 64-bit platforms, but Cygwin doesn't support 64-bit anyway.
STATIC_ASSERT(sizeof(Thread::LocalStorageKey) == sizeof(pthread_key_t));
intptr_t ptr_key = reinterpret_cast<intptr_t>(pthread_key);
return static_cast<Thread::LocalStorageKey>(ptr_key);
#else
return static_cast<Thread::LocalStorageKey>(pthread_key);
#endif
}
static pthread_key_t LocalKeyToPthreadKey(Thread::LocalStorageKey local_key) {
#if V8_OS_CYGWIN
STATIC_ASSERT(sizeof(Thread::LocalStorageKey) == sizeof(pthread_key_t));
intptr_t ptr_key = static_cast<intptr_t>(local_key);
return reinterpret_cast<pthread_key_t>(ptr_key);
#else
return static_cast<pthread_key_t>(local_key);
#endif
}
#ifdef V8_FAST_TLS_SUPPORTED
static Atomic32 tls_base_offset_initialized = 0;
intptr_t kMacTlsBaseOffset = 0;
// It's safe to do the initialization more that once, but it has to be
// done at least once.
static void InitializeTlsBaseOffset() {
const size_t kBufferSize = 128;
char buffer[kBufferSize];
size_t buffer_size = kBufferSize;
int ctl_name[] = { CTL_KERN , KERN_OSRELEASE };
if (sysctl(ctl_name, 2, buffer, &buffer_size, nullptr, 0) != 0) {
FATAL("V8 failed to get kernel version");
}
// The buffer now contains a string of the form XX.YY.ZZ, where
// XX is the major kernel version component.
// Make sure the buffer is 0-terminated.
buffer[kBufferSize - 1] = '\0';
char* period_pos = strchr(buffer, '.');
*period_pos = '\0';
int kernel_version_major =
static_cast<int>(strtol(buffer, nullptr, 10)); // NOLINT
// The constants below are taken from pthreads.s from the XNU kernel
// sources archive at www.opensource.apple.com.
if (kernel_version_major < 11) {
// 8.x.x (Tiger), 9.x.x (Leopard), 10.x.x (Snow Leopard) have the
// same offsets.
#if V8_HOST_ARCH_IA32
kMacTlsBaseOffset = 0x48;
#else
kMacTlsBaseOffset = 0x60;
#endif
} else {
// 11.x.x (Lion) changed the offset.
kMacTlsBaseOffset = 0;
}
Release_Store(&tls_base_offset_initialized, 1);
}
static void CheckFastTls(Thread::LocalStorageKey key) {
void* expected = reinterpret_cast<void*>(0x1234CAFE);
Thread::SetThreadLocal(key, expected);
void* actual = Thread::GetExistingThreadLocal(key);
if (expected != actual) {
FATAL("V8 failed to initialize fast TLS on current kernel");
}
Thread::SetThreadLocal(key, nullptr);
}
#endif // V8_FAST_TLS_SUPPORTED
Thread::LocalStorageKey Thread::CreateThreadLocalKey() {
#ifdef V8_FAST_TLS_SUPPORTED
bool check_fast_tls = false;
if (tls_base_offset_initialized == 0) {
check_fast_tls = true;
InitializeTlsBaseOffset();
}
#endif
pthread_key_t key;
int result = pthread_key_create(&key, nullptr);
DCHECK_EQ(0, result);
USE(result);
LocalStorageKey local_key = PthreadKeyToLocalKey(key);
#ifdef V8_FAST_TLS_SUPPORTED
// If we just initialized fast TLS support, make sure it works.
if (check_fast_tls) CheckFastTls(local_key);
#endif
return local_key;
}
void Thread::DeleteThreadLocalKey(LocalStorageKey key) {
pthread_key_t pthread_key = LocalKeyToPthreadKey(key);
int result = pthread_key_delete(pthread_key);
DCHECK_EQ(0, result);
USE(result);
}
void* Thread::GetThreadLocal(LocalStorageKey key) {
pthread_key_t pthread_key = LocalKeyToPthreadKey(key);
return pthread_getspecific(pthread_key);
}
void Thread::SetThreadLocal(LocalStorageKey key, void* value) {
pthread_key_t pthread_key = LocalKeyToPthreadKey(key);
int result = pthread_setspecific(pthread_key, value);
DCHECK_EQ(0, result);
USE(result);
}
#undef LOG_TAG
#undef MAP_ANONYMOUS
#undef MADV_FREE
} // namespace base
} // namespace v8
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