diff --git a/src/platform-cygwin.cc b/src/platform-cygwin.cc
index a9192775b7..c34330b3fb 100644
--- a/src/platform-cygwin.cc
+++ b/src/platform-cygwin.cc
@@ -51,9 +51,6 @@
 namespace v8 {
 namespace internal {
 
-// 0 is never a valid thread id
-static const pthread_t kNoThread = (pthread_t) 0;
-
 
 double ceiling(double x) {
   return ceil(x);
@@ -418,110 +415,6 @@ bool VirtualMemory::HasLazyCommits() {
 }
 
 
-class Thread::PlatformData : public Malloced {
- public:
-  PlatformData() : thread_(kNoThread) {}
-  pthread_t thread_;  // Thread handle for pthread.
-};
-
-
-Thread::Thread(const Options& options)
-    : data_(new PlatformData()),
-      stack_size_(options.stack_size()),
-      start_semaphore_(NULL) {
-  set_name(options.name());
-}
-
-
-Thread::~Thread() {
-  delete data_;
-}
-
-
-static void* ThreadEntry(void* arg) {
-  Thread* thread = reinterpret_cast<Thread*>(arg);
-  // This is also initialized by the first argument to pthread_create() but we
-  // don't know which thread will run first (the original thread or the new
-  // one) so we initialize it here too.
-  thread->data()->thread_ = pthread_self();
-  ASSERT(thread->data()->thread_ != kNoThread);
-  thread->NotifyStartedAndRun();
-  return NULL;
-}
-
-
-void Thread::set_name(const char* name) {
-  strncpy(name_, name, sizeof(name_));
-  name_[sizeof(name_) - 1] = '\0';
-}
-
-
-void Thread::Start() {
-  pthread_attr_t* attr_ptr = NULL;
-  pthread_attr_t attr;
-  if (stack_size_ > 0) {
-    pthread_attr_init(&attr);
-    pthread_attr_setstacksize(&attr, static_cast<size_t>(stack_size_));
-    attr_ptr = &attr;
-  }
-  pthread_create(&data_->thread_, attr_ptr, ThreadEntry, this);
-  ASSERT(data_->thread_ != kNoThread);
-}
-
-
-void Thread::Join() {
-  pthread_join(data_->thread_, NULL);
-}
-
-
-static inline Thread::LocalStorageKey PthreadKeyToLocalKey(
-    pthread_key_t pthread_key) {
-  // 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);
-}
-
-
-static inline pthread_key_t LocalKeyToPthreadKey(
-    Thread::LocalStorageKey local_key) {
-  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);
-}
-
-
-Thread::LocalStorageKey Thread::CreateThreadLocalKey() {
-  pthread_key_t key;
-  int result = pthread_key_create(&key, NULL);
-  USE(result);
-  ASSERT(result == 0);
-  return PthreadKeyToLocalKey(key);
-}
-
-
-void Thread::DeleteThreadLocalKey(LocalStorageKey key) {
-  pthread_key_t pthread_key = LocalKeyToPthreadKey(key);
-  int result = pthread_key_delete(pthread_key);
-  USE(result);
-  ASSERT(result == 0);
-}
-
-
-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);
-  pthread_setspecific(pthread_key, value);
-}
-
-
 class CygwinSemaphore : public Semaphore {
  public:
   explicit CygwinSemaphore(int count) {  sem_init(&sem_, 0, count); }
diff --git a/src/platform-freebsd.cc b/src/platform-freebsd.cc
index a0e0dbfd05..d7544db1ca 100644
--- a/src/platform-freebsd.cc
+++ b/src/platform-freebsd.cc
@@ -62,10 +62,6 @@
 namespace v8 {
 namespace internal {
 
-// 0 is never a valid thread id on FreeBSD since tids and pids share a
-// name space and pid 0 is used to kill the group (see man 2 kill).
-static const pthread_t kNoThread = (pthread_t) 0;
-
 
 double ceiling(double x) {
     // Correct as on OS X
@@ -397,90 +393,6 @@ bool VirtualMemory::HasLazyCommits() {
 }
 
 
-class Thread::PlatformData : public Malloced {
- public:
-  pthread_t thread_;  // Thread handle for pthread.
-};
-
-
-Thread::Thread(const Options& options)
-    : data_(new PlatformData),
-      stack_size_(options.stack_size()),
-      start_semaphore_(NULL) {
-  set_name(options.name());
-}
-
-
-Thread::~Thread() {
-  delete data_;
-}
-
-
-static void* ThreadEntry(void* arg) {
-  Thread* thread = reinterpret_cast<Thread*>(arg);
-  // This is also initialized by the first argument to pthread_create() but we
-  // don't know which thread will run first (the original thread or the new
-  // one) so we initialize it here too.
-  thread->data()->thread_ = pthread_self();
-  ASSERT(thread->data()->thread_ != kNoThread);
-  thread->NotifyStartedAndRun();
-  return NULL;
-}
-
-
-void Thread::set_name(const char* name) {
-  strncpy(name_, name, sizeof(name_));
-  name_[sizeof(name_) - 1] = '\0';
-}
-
-
-void Thread::Start() {
-  pthread_attr_t* attr_ptr = NULL;
-  pthread_attr_t attr;
-  if (stack_size_ > 0) {
-    pthread_attr_init(&attr);
-    pthread_attr_setstacksize(&attr, static_cast<size_t>(stack_size_));
-    attr_ptr = &attr;
-  }
-  pthread_create(&data_->thread_, attr_ptr, ThreadEntry, this);
-  ASSERT(data_->thread_ != kNoThread);
-}
-
-
-void Thread::Join() {
-  pthread_join(data_->thread_, NULL);
-}
-
-
-Thread::LocalStorageKey Thread::CreateThreadLocalKey() {
-  pthread_key_t key;
-  int result = pthread_key_create(&key, NULL);
-  USE(result);
-  ASSERT(result == 0);
-  return static_cast<LocalStorageKey>(key);
-}
-
-
-void Thread::DeleteThreadLocalKey(LocalStorageKey key) {
-  pthread_key_t pthread_key = static_cast<pthread_key_t>(key);
-  int result = pthread_key_delete(pthread_key);
-  USE(result);
-  ASSERT(result == 0);
-}
-
-
-void* Thread::GetThreadLocal(LocalStorageKey key) {
-  pthread_key_t pthread_key = static_cast<pthread_key_t>(key);
-  return pthread_getspecific(pthread_key);
-}
-
-
-void Thread::SetThreadLocal(LocalStorageKey key, void* value) {
-  pthread_key_t pthread_key = static_cast<pthread_key_t>(key);
-  pthread_setspecific(pthread_key, value);
-}
-
-
 class FreeBSDSemaphore : public Semaphore {
  public:
   explicit FreeBSDSemaphore(int count) {  sem_init(&sem_, 0, count); }
diff --git a/src/platform-linux.cc b/src/platform-linux.cc
index 438de22629..245dae4ace 100644
--- a/src/platform-linux.cc
+++ b/src/platform-linux.cc
@@ -75,10 +75,6 @@
 namespace v8 {
 namespace internal {
 
-// 0 is never a valid thread id on Linux since tids and pids share a
-// name space and pid 0 is reserved (see man 2 kill).
-static const pthread_t kNoThread = (pthread_t) 0;
-
 
 double ceiling(double x) {
   return ceil(x);
@@ -711,101 +707,6 @@ bool VirtualMemory::HasLazyCommits() {
 }
 
 
-class Thread::PlatformData : public Malloced {
- public:
-  PlatformData() : thread_(kNoThread) {}
-
-  pthread_t thread_;  // Thread handle for pthread.
-};
-
-Thread::Thread(const Options& options)
-    : data_(new PlatformData()),
-      stack_size_(options.stack_size()),
-      start_semaphore_(NULL) {
-  set_name(options.name());
-}
-
-
-Thread::~Thread() {
-  delete data_;
-}
-
-
-static void* ThreadEntry(void* arg) {
-  Thread* thread = reinterpret_cast<Thread*>(arg);
-  // This is also initialized by the first argument to pthread_create() but we
-  // don't know which thread will run first (the original thread or the new
-  // one) so we initialize it here too.
-#ifdef PR_SET_NAME
-  prctl(PR_SET_NAME,
-        reinterpret_cast<unsigned long>(thread->name()),  // NOLINT
-        0, 0, 0);
-#endif
-  thread->data()->thread_ = pthread_self();
-  ASSERT(thread->data()->thread_ != kNoThread);
-  thread->NotifyStartedAndRun();
-  return NULL;
-}
-
-
-void Thread::set_name(const char* name) {
-  strncpy(name_, name, sizeof(name_));
-  name_[sizeof(name_) - 1] = '\0';
-}
-
-
-void Thread::Start() {
-  pthread_attr_t* attr_ptr = NULL;
-#if defined(__native_client__)
-  // use default stack size.
-#else
-  pthread_attr_t attr;
-  if (stack_size_ > 0) {
-    pthread_attr_init(&attr);
-    pthread_attr_setstacksize(&attr, static_cast<size_t>(stack_size_));
-    attr_ptr = &attr;
-  }
-#endif
-  int result = pthread_create(&data_->thread_, attr_ptr, ThreadEntry, this);
-  CHECK_EQ(0, result);
-  ASSERT(data_->thread_ != kNoThread);
-}
-
-
-void Thread::Join() {
-  pthread_join(data_->thread_, NULL);
-}
-
-
-Thread::LocalStorageKey Thread::CreateThreadLocalKey() {
-  pthread_key_t key;
-  int result = pthread_key_create(&key, NULL);
-  USE(result);
-  ASSERT(result == 0);
-  return static_cast<LocalStorageKey>(key);
-}
-
-
-void Thread::DeleteThreadLocalKey(LocalStorageKey key) {
-  pthread_key_t pthread_key = static_cast<pthread_key_t>(key);
-  int result = pthread_key_delete(pthread_key);
-  USE(result);
-  ASSERT(result == 0);
-}
-
-
-void* Thread::GetThreadLocal(LocalStorageKey key) {
-  pthread_key_t pthread_key = static_cast<pthread_key_t>(key);
-  return pthread_getspecific(pthread_key);
-}
-
-
-void Thread::SetThreadLocal(LocalStorageKey key, void* value) {
-  pthread_key_t pthread_key = static_cast<pthread_key_t>(key);
-  pthread_setspecific(pthread_key, value);
-}
-
-
 class LinuxSemaphore : public Semaphore {
  public:
   explicit LinuxSemaphore(int count) {  sem_init(&sem_, 0, count); }
diff --git a/src/platform-macos.cc b/src/platform-macos.cc
index 30e90bb614..12a3e663f0 100644
--- a/src/platform-macos.cc
+++ b/src/platform-macos.cc
@@ -78,10 +78,6 @@ extern "C" {
 namespace v8 {
 namespace internal {
 
-// 0 is never a valid thread id on MacOSX since a pthread_t is
-// a pointer.
-static const pthread_t kNoThread = (pthread_t) 0;
-
 
 double ceiling(double x) {
   // Correct Mac OS X Leopard 'ceil' behavior.
@@ -421,177 +417,6 @@ bool VirtualMemory::HasLazyCommits() {
 }
 
 
-class Thread::PlatformData : public Malloced {
- public:
-  PlatformData() : thread_(kNoThread) {}
-  pthread_t thread_;  // Thread handle for pthread.
-};
-
-
-Thread::Thread(const Options& options)
-    : data_(new PlatformData),
-      stack_size_(options.stack_size()),
-      start_semaphore_(NULL) {
-  set_name(options.name());
-}
-
-
-Thread::~Thread() {
-  delete data_;
-}
-
-
-static void SetThreadName(const char* name) {
-  // 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)
-    return;
-
-  // Mac OS X does not expose the length limit of the name, so hardcode it.
-  static const int kMaxNameLength = 63;
-  USE(kMaxNameLength);
-  ASSERT(Thread::kMaxThreadNameLength <= kMaxNameLength);
-  dynamic_pthread_setname_np(name);
-}
-
-
-static void* ThreadEntry(void* arg) {
-  Thread* thread = reinterpret_cast<Thread*>(arg);
-  // This is also initialized by the first argument to pthread_create() but we
-  // don't know which thread will run first (the original thread or the new
-  // one) so we initialize it here too.
-  thread->data()->thread_ = pthread_self();
-  SetThreadName(thread->name());
-  ASSERT(thread->data()->thread_ != kNoThread);
-  thread->NotifyStartedAndRun();
-  return NULL;
-}
-
-
-void Thread::set_name(const char* name) {
-  strncpy(name_, name, sizeof(name_));
-  name_[sizeof(name_) - 1] = '\0';
-}
-
-
-void Thread::Start() {
-  pthread_attr_t* attr_ptr = NULL;
-  pthread_attr_t attr;
-  if (stack_size_ > 0) {
-    pthread_attr_init(&attr);
-    pthread_attr_setstacksize(&attr, static_cast<size_t>(stack_size_));
-    attr_ptr = &attr;
-  }
-  pthread_create(&data_->thread_, attr_ptr, ThreadEntry, this);
-  ASSERT(data_->thread_ != kNoThread);
-}
-
-
-void Thread::Join() {
-  pthread_join(data_->thread_, NULL);
-}
-
-
-#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, NULL, 0) != 0) {
-    V8_Fatal(__FILE__, __LINE__, "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, NULL, 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) {
-    V8_Fatal(__FILE__, __LINE__,
-             "V8 failed to initialize fast TLS on current kernel");
-  }
-  Thread::SetThreadLocal(key, NULL);
-}
-
-#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, NULL);
-  USE(result);
-  ASSERT(result == 0);
-  LocalStorageKey typed_key = static_cast<LocalStorageKey>(key);
-#ifdef V8_FAST_TLS_SUPPORTED
-  // If we just initialized fast TLS support, make sure it works.
-  if (check_fast_tls) CheckFastTls(typed_key);
-#endif
-  return typed_key;
-}
-
-
-void Thread::DeleteThreadLocalKey(LocalStorageKey key) {
-  pthread_key_t pthread_key = static_cast<pthread_key_t>(key);
-  int result = pthread_key_delete(pthread_key);
-  USE(result);
-  ASSERT(result == 0);
-}
-
-
-void* Thread::GetThreadLocal(LocalStorageKey key) {
-  pthread_key_t pthread_key = static_cast<pthread_key_t>(key);
-  return pthread_getspecific(pthread_key);
-}
-
-
-void Thread::SetThreadLocal(LocalStorageKey key, void* value) {
-  pthread_key_t pthread_key = static_cast<pthread_key_t>(key);
-  pthread_setspecific(pthread_key, value);
-}
-
-
 class MacOSSemaphore : public Semaphore {
  public:
   explicit MacOSSemaphore(int count) {
diff --git a/src/platform-openbsd.cc b/src/platform-openbsd.cc
index fbd07c62f8..4340094f12 100644
--- a/src/platform-openbsd.cc
+++ b/src/platform-openbsd.cc
@@ -477,96 +477,6 @@ bool VirtualMemory::HasLazyCommits() {
 }
 
 
-class Thread::PlatformData : public Malloced {
- public:
-  PlatformData() : thread_(kNoThread) {}
-
-  pthread_t thread_;  // Thread handle for pthread.
-};
-
-Thread::Thread(const Options& options)
-    : data_(new PlatformData()),
-      stack_size_(options.stack_size()),
-      start_semaphore_(NULL) {
-  set_name(options.name());
-}
-
-
-Thread::~Thread() {
-  delete data_;
-}
-
-
-static void* ThreadEntry(void* arg) {
-  Thread* thread = reinterpret_cast<Thread*>(arg);
-  // This is also initialized by the first argument to pthread_create() but we
-  // don't know which thread will run first (the original thread or the new
-  // one) so we initialize it here too.
-#ifdef PR_SET_NAME
-  prctl(PR_SET_NAME,
-        reinterpret_cast<unsigned long>(thread->name()),  // NOLINT
-        0, 0, 0);
-#endif
-  thread->data()->thread_ = pthread_self();
-  ASSERT(thread->data()->thread_ != kNoThread);
-  thread->NotifyStartedAndRun();
-  return NULL;
-}
-
-
-void Thread::set_name(const char* name) {
-  strncpy(name_, name, sizeof(name_));
-  name_[sizeof(name_) - 1] = '\0';
-}
-
-
-void Thread::Start() {
-  pthread_attr_t* attr_ptr = NULL;
-  pthread_attr_t attr;
-  if (stack_size_ > 0) {
-    pthread_attr_init(&attr);
-    pthread_attr_setstacksize(&attr, static_cast<size_t>(stack_size_));
-    attr_ptr = &attr;
-  }
-  pthread_create(&data_->thread_, attr_ptr, ThreadEntry, this);
-  ASSERT(data_->thread_ != kNoThread);
-}
-
-
-void Thread::Join() {
-  pthread_join(data_->thread_, NULL);
-}
-
-
-Thread::LocalStorageKey Thread::CreateThreadLocalKey() {
-  pthread_key_t key;
-  int result = pthread_key_create(&key, NULL);
-  USE(result);
-  ASSERT(result == 0);
-  return static_cast<LocalStorageKey>(key);
-}
-
-
-void Thread::DeleteThreadLocalKey(LocalStorageKey key) {
-  pthread_key_t pthread_key = static_cast<pthread_key_t>(key);
-  int result = pthread_key_delete(pthread_key);
-  USE(result);
-  ASSERT(result == 0);
-}
-
-
-void* Thread::GetThreadLocal(LocalStorageKey key) {
-  pthread_key_t pthread_key = static_cast<pthread_key_t>(key);
-  return pthread_getspecific(pthread_key);
-}
-
-
-void Thread::SetThreadLocal(LocalStorageKey key, void* value) {
-  pthread_key_t pthread_key = static_cast<pthread_key_t>(key);
-  pthread_setspecific(pthread_key, value);
-}
-
-
 class OpenBSDSemaphore : public Semaphore {
  public:
   explicit OpenBSDSemaphore(int count) {  sem_init(&sem_, 0, count); }
diff --git a/src/platform-posix.cc b/src/platform-posix.cc
index 47fa5e55a0..ff5f70addc 100644
--- a/src/platform-posix.cc
+++ b/src/platform-posix.cc
@@ -31,7 +31,11 @@
 
 #include "platform-posix.h"
 
+#include <dlfcn.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 <unistd.h>
 #include <errno.h>
@@ -43,6 +47,13 @@
 #include <sys/time.h>
 #include <sys/types.h>
 #include <sys/stat.h>
+#if defined(__linux__)
+#include <sys/prctl.h>  // for prctl
+#endif
+#if defined(__APPLE__) || defined(__DragonFly__) || defined(__FreeBSD__) || \
+    defined(__NetBSD__) || defined(__OpenBSD__)
+#include <sys/sysctl.h>  // for sysctl
+#endif
 
 #include <arpa/inet.h>
 #include <netinet/in.h>
@@ -63,6 +74,9 @@
 namespace v8 {
 namespace internal {
 
+// 0 is never a valid thread id.
+static const pthread_t kNoThread = (pthread_t) 0;
+
 
 // Maximum size of the virtual memory.  0 means there is no artificial
 // limit.
@@ -217,7 +231,7 @@ UNARY_MATH_FUNCTION(log, CreateTranscendentalFunction(TranscendentalCache::LOG))
 UNARY_MATH_FUNCTION(exp, CreateExpFunction())
 UNARY_MATH_FUNCTION(sqrt, CreateSqrtFunction())
 
-#undef MATH_FUNCTION
+#undef UNARY_MATH_FUNCTION
 
 
 void lazily_initialize_fast_exp() {
@@ -468,8 +482,229 @@ void OS::StrNCpy(Vector<char> dest, const char* src, size_t n) {
 // POSIX thread support.
 //
 
+class Thread::PlatformData : public Malloced {
+ public:
+  PlatformData() : thread_(kNoThread) {}
+  pthread_t thread_;  // Thread handle for pthread.
+};
+
+Thread::Thread(const Options& options)
+    : data_(new PlatformData),
+      stack_size_(options.stack_size()),
+      start_semaphore_(NULL) {
+  set_name(options.name());
+}
+
+
+Thread::~Thread() {
+  delete data_;
+}
+
+
+static void SetThreadName(const char* name) {
+  int result = 0;
+#if defined(__DragonFly__) || defined(__FreeBSD__) || defined(__OpenBSD__)
+  result = pthread_set_name_np(pthread_self(), name);
+#elif defined(__NetBSD__)
+  STATIC_ASSERT(Thread::kMaxThreadNameLength <= PTHREAD_MAX_NAMELEN_NP);
+  result = pthread_setname_np(pthread_self(), "%s", name);
+#elif defined(__APPLE__)
+  // 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 == NULL)
+    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);
+  result = dynamic_pthread_setname_np(name);
+#elif defined(PR_SET_NAME)
+  result = prctl(PR_SET_NAME,
+                 reinterpret_cast<unsigned long>(name),  // NOLINT
+                 0, 0, 0);
+#endif
+  ASSERT_EQ(0, result);
+  USE(result);
+}
+
+
+static void* ThreadEntry(void* arg) {
+  Thread* thread = reinterpret_cast<Thread*>(arg);
+  // This is also initialized by the first argument to pthread_create() but we
+  // don't know which thread will run first (the original thread or the new
+  // one) so we initialize it here too.
+  thread->data()->thread_ = pthread_self();
+  SetThreadName(thread->name());
+  ASSERT(thread->data()->thread_ != kNoThread);
+  thread->NotifyStartedAndRun();
+  return NULL;
+}
+
+
+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);
+  ASSERT_EQ(0, result);
+  // Native client uses default stack size.
+#if !defined(__native_client__)
+  if (stack_size_ > 0) {
+    result = pthread_attr_setstacksize(&attr, static_cast<size_t>(stack_size_));
+    ASSERT_EQ(0, result);
+  }
+#endif
+  result = pthread_create(&data_->thread_, &attr, ThreadEntry, this);
+  ASSERT_EQ(0, result);
+  result = pthread_attr_destroy(&attr);
+  ASSERT_EQ(0, result);
+  ASSERT(data_->thread_ != kNoThread);
+  USE(result);
+}
+
+
+void Thread::Join() {
+  pthread_join(data_->thread_, NULL);
+}
+
+
 void Thread::YieldCPU() {
-  sched_yield();
+  int result = sched_yield();
+  ASSERT_EQ(0, result);
+  USE(result);
+}
+
+
+static Thread::LocalStorageKey PthreadKeyToLocalKey(pthread_key_t pthread_key) {
+#if defined(__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 defined(__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, NULL, 0) != 0) {
+    V8_Fatal(__FILE__, __LINE__, "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, NULL, 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) {
+    V8_Fatal(__FILE__, __LINE__,
+             "V8 failed to initialize fast TLS on current kernel");
+  }
+  Thread::SetThreadLocal(key, NULL);
+}
+
+#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, NULL);
+  ASSERT_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);
+  ASSERT_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);
+  ASSERT_EQ(0, result);
+  USE(result);
 }
 
 
diff --git a/src/platform-solaris.cc b/src/platform-solaris.cc
index 53d8983be4..1ecca16507 100644
--- a/src/platform-solaris.cc
+++ b/src/platform-solaris.cc
@@ -81,11 +81,6 @@ namespace v8 {
 namespace internal {
 
 
-// 0 is never a valid thread id on Solaris since the main thread is 1 and
-// subsequent have their ids incremented from there
-static const pthread_t kNoThread = (pthread_t) 0;
-
-
 double ceiling(double x) {
   return ceil(x);
 }
@@ -414,90 +409,6 @@ bool VirtualMemory::HasLazyCommits() {
 }
 
 
-class Thread::PlatformData : public Malloced {
- public:
-  PlatformData() : thread_(kNoThread) {  }
-
-  pthread_t thread_;  // Thread handle for pthread.
-};
-
-
-Thread::Thread(const Options& options)
-    : data_(new PlatformData()),
-      stack_size_(options.stack_size()),
-      start_semaphore_(NULL) {
-  set_name(options.name());
-}
-
-
-Thread::~Thread() {
-  delete data_;
-}
-
-
-static void* ThreadEntry(void* arg) {
-  Thread* thread = reinterpret_cast<Thread*>(arg);
-  // This is also initialized by the first argument to pthread_create() but we
-  // don't know which thread will run first (the original thread or the new
-  // one) so we initialize it here too.
-  thread->data()->thread_ = pthread_self();
-  ASSERT(thread->data()->thread_ != kNoThread);
-  thread->NotifyStartedAndRun();
-  return NULL;
-}
-
-
-void Thread::set_name(const char* name) {
-  strncpy(name_, name, sizeof(name_));
-  name_[sizeof(name_) - 1] = '\0';
-}
-
-
-void Thread::Start() {
-  pthread_attr_t attr;
-  if (stack_size_ > 0) {
-    pthread_attr_init(&attr);
-    pthread_attr_setstacksize(&attr, static_cast<size_t>(stack_size_));
-  }
-  pthread_create(&data_->thread_, NULL, ThreadEntry, this);
-  ASSERT(data_->thread_ != kNoThread);
-}
-
-
-void Thread::Join() {
-  pthread_join(data_->thread_, NULL);
-}
-
-
-Thread::LocalStorageKey Thread::CreateThreadLocalKey() {
-  pthread_key_t key;
-  int result = pthread_key_create(&key, NULL);
-  USE(result);
-  ASSERT(result == 0);
-  return static_cast<LocalStorageKey>(key);
-}
-
-
-void Thread::DeleteThreadLocalKey(LocalStorageKey key) {
-  pthread_key_t pthread_key = static_cast<pthread_key_t>(key);
-  int result = pthread_key_delete(pthread_key);
-  USE(result);
-  ASSERT(result == 0);
-}
-
-
-void* Thread::GetThreadLocal(LocalStorageKey key) {
-  pthread_key_t pthread_key = static_cast<pthread_key_t>(key);
-  return pthread_getspecific(pthread_key);
-}
-
-
-void Thread::SetThreadLocal(LocalStorageKey key, void* value) {
-  pthread_key_t pthread_key = static_cast<pthread_key_t>(key);
-  pthread_setspecific(pthread_key, value);
-}
-
-
 class SolarisSemaphore : public Semaphore {
  public:
   explicit SolarisSemaphore(int count) {  sem_init(&sem_, 0, count); }