From 0ed25321cf3d2ca54dd148cc58e79712b73b9b3e Mon Sep 17 00:00:00 2001
From: unknown <cyg_server@.(none)>
Date: Fri, 12 Nov 2010 00:15:30 +0100
Subject: [PATCH] Patch for Cygwin

---
 SConstruct             |    3 +-
 src/SConscript         |    1 +
 src/platform-cygwin.cc |  865 ++++++++++++++++++++++++++++++++++++++++++++++++
 src/platform.h         |    5 +
 src/utils.h            |    2 +-
 tools/utils.py         |    2 +
 6 files changed, 875 insertions(+), 3 deletions(-)
 create mode 100644 src/platform-cygwin.cc

diff --git a/SConstruct b/SConstruct
index 820c1a1..7107e91 100644
--- a/SConstruct
+++ b/SConstruct
@@ -292,7 +292,6 @@ V8_EXTRA_FLAGS = {
   'gcc': {
     'all': {
       'WARNINGFLAGS': ['-Wall',
-                       '-Werror',
                        '-W',
                        '-Wno-unused-parameter',
                        '-Wnon-virtual-dtor']
@@ -666,7 +665,7 @@ SIMPLE_OPTIONS = {
     'help': 'the toolchain to use (%s)' % TOOLCHAIN_GUESS
   },
   'os': {
-    'values': ['freebsd', 'linux', 'macos', 'win32', 'android', 'openbsd', 'solaris'],
+    'values': ['freebsd', 'linux', 'macos', 'win32', 'android', 'openbsd', 'solaris', 'cygwin'],
     'default': OS_GUESS,
     'help': 'the os to build for (%s)' % OS_GUESS
   },
diff --git a/src/SConscript b/src/SConscript
index 8995d48..ef5485d 100755
--- a/src/SConscript
+++ b/src/SConscript
@@ -204,6 +204,7 @@ SOURCES = {
   'os:android': ['platform-linux.cc', 'platform-posix.cc'],
   'os:macos':   ['platform-macos.cc', 'platform-posix.cc'],
   'os:solaris': ['platform-solaris.cc', 'platform-posix.cc'],
+  'os:cygwin':  ['platform-cygwin.cc', 'platform-posix.cc'],
   'os:nullos':  ['platform-nullos.cc'],
   'os:win32':   ['platform-win32.cc'],
   'mode:release': [],
diff --git a/src/platform-cygwin.cc b/src/platform-cygwin.cc
new file mode 100644
index 0000000..ad0ad8c
--- /dev/null
+++ b/src/platform-cygwin.cc
@@ -0,0 +1,865 @@
+// Copyright 2006-2008 the V8 project authors. All rights reserved.
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+//       notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+//       copyright notice, this list of conditions and the following
+//       disclaimer in the documentation and/or other materials provided
+//       with the distribution.
+//     * Neither the name of Google Inc. nor the names of its
+//       contributors may be used to endorse or promote products derived
+//       from this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+// Platform specific code for Cygwin goes here. For the POSIX comaptible parts
+// the implementation is in platform-posix.cc.
+
+#include <pthread.h>
+#include <semaphore.h>
+#include <signal.h>
+#include <sys/time.h>
+#include <sys/resource.h>
+#include <sys/types.h>
+#include <stdlib.h>
+
+// Ubuntu Dapper requires memory pages to be marked as
+// executable. Otherwise, OS raises an exception when executing code
+// in that page.
+#include <sys/types.h>  // mmap & munmap
+#include <sys/mman.h>   // mmap & munmap
+#include <sys/stat.h>   // open
+#include <fcntl.h>      // open
+#include <unistd.h>     // sysconf
+#ifdef __GLIBC__
+#include <execinfo.h>   // backtrace, backtrace_symbols
+#endif  // def __GLIBC__
+#include <strings.h>    // index
+#include <errno.h>
+#include <stdarg.h>
+
+#undef MAP_TYPE
+
+#include "v8.h"
+
+#include "platform.h"
+#include "top.h"
+#include "v8threads.h"
+
+
+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);
+}
+
+
+void OS::Setup() {
+  // Seed the random number generator.
+  // Convert the current time to a 64-bit integer first, before converting it
+  // to an unsigned. Going directly can cause an overflow and the seed to be
+  // set to all ones. The seed will be identical for different instances that
+  // call this setup code within the same millisecond.
+  uint64_t seed = static_cast<uint64_t>(TimeCurrentMillis());
+  srandom(static_cast<unsigned int>(seed));
+}
+
+
+uint64_t OS::CpuFeaturesImpliedByPlatform() {
+#if (defined(__VFP_FP__) && !defined(__SOFTFP__))
+  // Here gcc is telling us that we are on an ARM and gcc is assuming that we
+  // have VFP3 instructions.  If gcc can assume it then so can we.
+  return 1u << VFP3;
+#elif CAN_USE_ARMV7_INSTRUCTIONS
+  return 1u << ARMv7;
+#else
+  return 0;  // Linux runs on anything.
+#endif
+}
+
+
+#ifdef __arm__
+bool OS::ArmCpuHasFeature(CpuFeature feature) {
+  const char* search_string = NULL;
+  const char* file_name = "/proc/cpuinfo";
+  // Simple detection of VFP at runtime for Linux.
+  // It is based on /proc/cpuinfo, which reveals hardware configuration
+  // to user-space applications.  According to ARM (mid 2009), no similar
+  // facility is universally available on the ARM architectures,
+  // so it's up to individual OSes to provide such.
+  //
+  // This is written as a straight shot one pass parser
+  // and not using STL string and ifstream because,
+  // on Linux, it's reading from a (non-mmap-able)
+  // character special device.
+  switch (feature) {
+    case VFP3:
+      search_string = "vfp";
+      break;
+    case ARMv7:
+      search_string = "ARMv7";
+      break;
+    default:
+      UNREACHABLE();
+  }
+
+  FILE* f = NULL;
+  const char* what = search_string;
+
+  if (NULL == (f = fopen(file_name, "r")))
+    return false;
+
+  int k;
+  while (EOF != (k = fgetc(f))) {
+    if (k == *what) {
+      ++what;
+      while ((*what != '\0') && (*what == fgetc(f))) {
+        ++what;
+      }
+      if (*what == '\0') {
+        fclose(f);
+        return true;
+      } else {
+        what = search_string;
+      }
+    }
+  }
+  fclose(f);
+
+  // Did not find string in the proc file.
+  return false;
+}
+#endif  // def __arm__
+
+
+int OS::ActivationFrameAlignment() {
+#ifdef 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;
+#endif
+  // With gcc 4.4 the tree vectorization optimizer can generate code
+  // that requires 16 byte alignment such as movdqa on x86.
+  return 16;
+}
+
+void OS::ReleaseStore(volatile AtomicWord* ptr, AtomicWord value) {
+  __asm__ __volatile__("" : : : "memory");
+  // An x86 store acts as a release barrier.
+  *ptr = value;
+}
+
+const char* OS::LocalTimezone(double time) {
+  if (isnan(time)) return "";
+  time_t tv = static_cast<time_t>(floor(time/msPerSecond));
+  struct tm* t = localtime(&tv);
+  if (NULL == t) return "";
+  return tzname[0];  // The location of the timezone string on Cywin.
+}
+
+
+double OS::LocalTimeOffset() {
+  //
+  // On Cygwin, struct tm does not contain a tm_gmtoff field.
+  time_t utc = time(NULL);
+  ASSERT(utc != -1);
+  struct tm* loc = localtime(&utc);
+  ASSERT(loc != NULL);
+  return static_cast<double>((mktime(loc) - utc) * msPerSecond);
+}
+
+
+// We keep the lowest and highest addresses mapped as a quick way of
+// determining that pointers are outside the heap (used mostly in assertions
+// and verification).  The estimate is conservative, ie, not all addresses in
+// 'allocated' space are actually allocated to our heap.  The range is
+// [lowest, highest), inclusive on the low and and exclusive on the high end.
+static void* lowest_ever_allocated = reinterpret_cast<void*>(-1);
+static void* highest_ever_allocated = reinterpret_cast<void*>(0);
+
+
+static void UpdateAllocatedSpaceLimits(void* address, int size) {
+  lowest_ever_allocated = Min(lowest_ever_allocated, address);
+  highest_ever_allocated =
+      Max(highest_ever_allocated,
+          reinterpret_cast<void*>(reinterpret_cast<char*>(address) + size));
+}
+
+
+bool OS::IsOutsideAllocatedSpace(void* address) {
+  return address < lowest_ever_allocated || address >= highest_ever_allocated;
+}
+
+
+size_t OS::AllocateAlignment() {
+  return sysconf(_SC_PAGESIZE);
+}
+
+
+void* OS::Allocate(const size_t requested,
+                   size_t* allocated,
+                   bool is_executable) {
+  const size_t msize = RoundUp(requested, sysconf(_SC_PAGESIZE));
+  int prot = PROT_READ | PROT_WRITE | (is_executable ? PROT_EXEC : 0);
+  void* mbase = mmap(NULL, msize, prot, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
+  if (mbase == MAP_FAILED) {
+    LOG(StringEvent("OS::Allocate", "mmap failed"));
+    return NULL;
+  }
+  *allocated = msize;
+  UpdateAllocatedSpaceLimits(mbase, msize);
+  return mbase;
+}
+
+
+void OS::Free(void* address, const size_t size) {
+  // TODO(1240712): munmap has a return value which is ignored here.
+  int result = munmap(address, size);
+  USE(result);
+  ASSERT(result == 0);
+}
+
+
+#ifdef ENABLE_HEAP_PROTECTION
+
+void OS::Protect(void* address, size_t size) {
+  // TODO(1240712): mprotect has a return value which is ignored here.
+  mprotect(address, size, PROT_READ);
+}
+
+
+void OS::Unprotect(void* address, size_t size, bool is_executable) {
+  // TODO(1240712): mprotect has a return value which is ignored here.
+  int prot = PROT_READ | PROT_WRITE | (is_executable ? PROT_EXEC : 0);
+  mprotect(address, size, prot);
+}
+
+#endif
+
+
+void OS::Sleep(int milliseconds) {
+  unsigned int ms = static_cast<unsigned int>(milliseconds);
+  usleep(1000 * ms);
+}
+
+
+void OS::Abort() {
+  // Redirect to std abort to signal abnormal program termination.
+  abort();
+}
+
+
+void OS::DebugBreak() {
+// TODO(lrn): Introduce processor define for runtime system (!= V8_ARCH_x,
+//  which is the architecture of generated code).
+#if (defined(__arm__) || defined(__thumb__)) && \
+    defined(CAN_USE_ARMV5_INSTRUCTIONS)
+  asm("bkpt 0");
+#elif defined(__mips__)
+  asm("break");
+#else
+  asm("int $3");
+#endif
+}
+
+
+class PosixMemoryMappedFile : public OS::MemoryMappedFile {
+ public:
+  PosixMemoryMappedFile(FILE* file, void* memory, int size)
+    : file_(file), memory_(memory), size_(size) { }
+  virtual ~PosixMemoryMappedFile();
+  virtual void* memory() { return memory_; }
+ private:
+  FILE* file_;
+  void* memory_;
+  int size_;
+};
+
+
+OS::MemoryMappedFile* OS::MemoryMappedFile::create(const char* name, int size,
+    void* initial) {
+  FILE* file = fopen(name, "w+");
+  if (file == NULL) return NULL;
+  int result = fwrite(initial, size, 1, file);
+  if (result < 1) {
+    fclose(file);
+    return NULL;
+  }
+  void* memory =
+      mmap(0, size, PROT_READ | PROT_WRITE, MAP_SHARED, fileno(file), 0);
+  return new PosixMemoryMappedFile(file, memory, size);
+}
+
+
+PosixMemoryMappedFile::~PosixMemoryMappedFile() {
+  if (memory_) munmap(memory_, size_);
+  fclose(file_);
+}
+
+
+void OS::LogSharedLibraryAddresses() {
+#ifdef ENABLE_LOGGING_AND_PROFILING
+  // This function assumes that the layout of the file is as follows:
+  // hex_start_addr-hex_end_addr rwxp <unused data> [binary_file_name]
+  // If we encounter an unexpected situation we abort scanning further entries.
+  FILE* fp = fopen("/proc/self/maps", "r");
+  if (fp == NULL) return;
+
+  // Allocate enough room to be able to store a full file name.
+  const int kLibNameLen = FILENAME_MAX + 1;
+  char* lib_name = reinterpret_cast<char*>(malloc(kLibNameLen));
+
+  // This loop will terminate once the scanning hits an EOF.
+  while (true) {
+    uintptr_t start, end;
+    char attr_r, attr_w, attr_x, attr_p;
+    // Parse the addresses and permission bits at the beginning of the line.
+    if (fscanf(fp, "%" V8PRIxPTR "-%" V8PRIxPTR, &start, &end) != 2) break;
+    if (fscanf(fp, " %c%c%c%c", &attr_r, &attr_w, &attr_x, &attr_p) != 4) break;
+
+    int c;
+    if (attr_r == 'r' && attr_w != 'w' && attr_x == 'x') {
+      // Found a read-only executable entry. Skip characters until we reach
+      // the beginning of the filename or the end of the line.
+      do {
+        c = getc(fp);
+      } while ((c != EOF) && (c != '\n') && (c != '/'));
+      if (c == EOF) break;  // EOF: Was unexpected, just exit.
+
+      // Process the filename if found.
+      if (c == '/') {
+        ungetc(c, fp);  // Push the '/' back into the stream to be read below.
+
+        // Read to the end of the line. Exit if the read fails.
+        if (fgets(lib_name, kLibNameLen, fp) == NULL) break;
+
+        // Drop the newline character read by fgets. We do not need to check
+        // for a zero-length string because we know that we at least read the
+        // '/' character.
+        lib_name[strlen(lib_name) - 1] = '\0';
+      } else {
+        // No library name found, just record the raw address range.
+        snprintf(lib_name, kLibNameLen,
+                 "%08" V8PRIxPTR "-%08" V8PRIxPTR, start, end);
+      }
+      LOG(SharedLibraryEvent(lib_name, start, end));
+    } else {
+      // Entry not describing executable data. Skip to end of line to setup
+      // reading the next entry.
+      do {
+        c = getc(fp);
+      } while ((c != EOF) && (c != '\n'));
+      if (c == EOF) break;
+    }
+  }
+  free(lib_name);
+  fclose(fp);
+#endif
+}
+
+
+void OS::SignalCodeMovingGC() {
+}
+
+
+int OS::StackWalk(Vector<OS::StackFrame> frames) {
+  // backtrace is a glibc extension.
+#ifdef __GLIBC__
+  int frames_size = frames.length();
+  ScopedVector<void*> addresses(frames_size);
+
+  int frames_count = backtrace(addresses.start(), frames_size);
+
+  char** symbols = backtrace_symbols(addresses.start(), frames_count);
+  if (symbols == NULL) {
+    return kStackWalkError;
+  }
+
+  for (int i = 0; i < frames_count; i++) {
+    frames[i].address = addresses[i];
+    // Format a text representation of the frame based on the information
+    // available.
+    SNPrintF(MutableCStrVector(frames[i].text, kStackWalkMaxTextLen),
+             "%s",
+             symbols[i]);
+    // Make sure line termination is in place.
+    frames[i].text[kStackWalkMaxTextLen - 1] = '\0';
+  }
+
+  free(symbols);
+
+  return frames_count;
+#else  // ndef __GLIBC__
+  return 0;
+#endif  // ndef __GLIBC__
+}
+
+
+// Constants used for mmap.
+static const int kMmapFd = -1;
+static const int kMmapFdOffset = 0;
+
+
+VirtualMemory::VirtualMemory(size_t size) {
+  address_ = mmap(NULL, size, PROT_NONE,
+                  MAP_PRIVATE | MAP_ANONYMOUS | MAP_NORESERVE,
+                  kMmapFd, kMmapFdOffset);
+  size_ = size;
+}
+
+
+VirtualMemory::~VirtualMemory() {
+  if (IsReserved()) {
+    if (0 == munmap(address(), size())) address_ = MAP_FAILED;
+  }
+}
+
+
+bool VirtualMemory::IsReserved() {
+  return address_ != MAP_FAILED;
+}
+
+
+bool VirtualMemory::Commit(void* address, size_t size, bool is_executable) {
+  int prot = PROT_READ | PROT_WRITE | (is_executable ? PROT_EXEC : 0);
+
+#ifdef HAS_MAP_FIXED
+  if (MAP_FAILED == mmap(address, size, prot,
+                         MAP_PRIVATE | MAP_ANONYMOUS, // | MAP_FIXED, - Cygwin doesn't have MAP_FIXED
+                         kMmapFd, kMmapFdOffset)) {
+    return false;
+  }
+#else
+  if (mprotect(address, size, prot) != 0) {
+    return false;
+  }
+#endif
+
+  UpdateAllocatedSpaceLimits(address, size);
+  return true;
+}
+
+
+bool VirtualMemory::Uncommit(void* address, size_t size) {
+  return mmap(address, size, PROT_NONE,
+              MAP_PRIVATE | MAP_ANONYMOUS | MAP_NORESERVE, // | MAP_FIXED, - Cygwin doesn't have MAP_FIXED
+              kMmapFd, kMmapFdOffset) != MAP_FAILED;
+}
+
+
+class ThreadHandle::PlatformData : public Malloced {
+ public:
+  explicit PlatformData(ThreadHandle::Kind kind) {
+    Initialize(kind);
+  }
+
+  void Initialize(ThreadHandle::Kind kind) {
+    switch (kind) {
+      case ThreadHandle::SELF: thread_ = pthread_self(); break;
+      case ThreadHandle::INVALID: thread_ = kNoThread; break;
+    }
+  }
+
+  pthread_t thread_;  // Thread handle for pthread.
+};
+
+
+ThreadHandle::ThreadHandle(Kind kind) {
+  data_ = new PlatformData(kind);
+}
+
+
+void ThreadHandle::Initialize(ThreadHandle::Kind kind) {
+  data_->Initialize(kind);
+}
+
+
+ThreadHandle::~ThreadHandle() {
+  delete data_;
+}
+
+
+bool ThreadHandle::IsSelf() const {
+  return pthread_equal(data_->thread_, pthread_self());
+}
+
+
+bool ThreadHandle::IsValid() const {
+  return data_->thread_ != kNoThread;
+}
+
+
+Thread::Thread() : ThreadHandle(ThreadHandle::INVALID) {
+}
+
+
+Thread::~Thread() {
+}
+
+
+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->thread_handle_data()->thread_ = pthread_self();
+  ASSERT(thread->IsValid());
+  thread->Run();
+  return NULL;
+}
+
+
+void Thread::Start() {
+  pthread_create(&thread_handle_data()->thread_, NULL, ThreadEntry, this);
+  ASSERT(IsValid());
+}
+
+
+void Thread::Join() {
+  pthread_join(thread_handle_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);
+}
+
+
+void Thread::YieldCPU() {
+  sched_yield();
+}
+
+
+class CygwinMutex : public Mutex {
+ public:
+
+  CygwinMutex() {
+    pthread_mutexattr_t attrs;
+    memset(&attrs, 0, sizeof(attrs));
+
+    int result = pthread_mutexattr_init(&attrs);
+    ASSERT(result == 0);
+    result = pthread_mutexattr_settype(&attrs, PTHREAD_MUTEX_RECURSIVE);
+    ASSERT(result == 0);
+    result = pthread_mutex_init(&mutex_, &attrs);
+    ASSERT(result == 0);
+  }
+
+  virtual ~CygwinMutex() { pthread_mutex_destroy(&mutex_); }
+
+  virtual int Lock() {
+    int result = pthread_mutex_lock(&mutex_);
+    return result;
+  }
+
+  virtual int Unlock() {
+    int result = pthread_mutex_unlock(&mutex_);
+    return result;
+  }
+
+ private:
+  pthread_mutex_t mutex_;   // Pthread mutex for POSIX platforms.
+};
+
+
+Mutex* OS::CreateMutex() {
+  return new CygwinMutex();
+}
+
+
+class CygwinSemaphore : public Semaphore {
+ public:
+  explicit CygwinSemaphore(int count) {  sem_init(&sem_, 0, count); }
+  virtual ~CygwinSemaphore() { sem_destroy(&sem_); }
+
+  virtual void Wait();
+  virtual bool Wait(int timeout);
+  virtual void Signal() { sem_post(&sem_); }
+ private:
+  sem_t sem_;
+};
+
+
+void CygwinSemaphore::Wait() {
+  while (true) {
+    int result = sem_wait(&sem_);
+    if (result == 0) return;  // Successfully got semaphore.
+    CHECK(result == -1 && errno == EINTR);  // Signal caused spurious wakeup.
+  }
+}
+
+
+#ifndef TIMEVAL_TO_TIMESPEC
+#define TIMEVAL_TO_TIMESPEC(tv, ts) do {                            \
+    (ts)->tv_sec = (tv)->tv_sec;                                    \
+    (ts)->tv_nsec = (tv)->tv_usec * 1000;                           \
+} while (false)
+#endif
+
+
+bool CygwinSemaphore::Wait(int timeout) {
+  const long kOneSecondMicros = 1000000;  // NOLINT
+
+  // Split timeout into second and nanosecond parts.
+  struct timeval delta;
+  delta.tv_usec = timeout % kOneSecondMicros;
+  delta.tv_sec = timeout / kOneSecondMicros;
+
+  struct timeval current_time;
+  // Get the current time.
+  if (gettimeofday(&current_time, NULL) == -1) {
+    return false;
+  }
+
+  // Calculate time for end of timeout.
+  struct timeval end_time;
+  timeradd(&current_time, &delta, &end_time);
+
+  struct timespec ts;
+  TIMEVAL_TO_TIMESPEC(&end_time, &ts);
+  // Wait for semaphore signalled or timeout.
+  while (true) {
+    int result = sem_timedwait(&sem_, &ts);
+    if (result == 0) return true;  // Successfully got semaphore.
+    if (result > 0) {
+      // For glibc prior to 2.3.4 sem_timedwait returns the error instead of -1.
+      errno = result;
+      result = -1;
+    }
+    if (result == -1 && errno == ETIMEDOUT) return false;  // Timeout.
+    CHECK(result == -1 && errno == EINTR);  // Signal caused spurious wakeup.
+  }
+}
+
+
+Semaphore* OS::CreateSemaphore(int count) {
+  return new CygwinSemaphore(count);
+}
+
+
+#ifdef ENABLE_LOGGING_AND_PROFILING
+
+static Sampler* active_sampler_ = NULL;
+static pthread_t vm_thread_ = 0;
+
+
+#if !defined(__GLIBC__) && (defined(__arm__) || defined(__thumb__))
+// Android runs a fairly new Linux kernel, so signal info is there,
+// but the C library doesn't have the structs defined.
+
+struct sigcontext {
+  uint32_t trap_no;
+  uint32_t error_code;
+  uint32_t oldmask;
+  uint32_t gregs[16];
+  uint32_t arm_cpsr;
+  uint32_t fault_address;
+};
+typedef uint32_t __sigset_t;
+typedef struct sigcontext mcontext_t;
+typedef struct ucontext {
+  uint32_t uc_flags;
+  struct ucontext* uc_link;
+  stack_t uc_stack;
+  mcontext_t uc_mcontext;
+  __sigset_t uc_sigmask;
+} ucontext_t;
+enum ArmRegisters {R15 = 15, R13 = 13, R11 = 11};
+
+#endif
+
+
+// A function that determines if a signal handler is called in the context
+// of a VM thread.
+//
+// The problem is that SIGPROF signal can be delivered to an arbitrary thread
+// (see http://code.google.com/p/google-perftools/issues/detail?id=106#c2)
+// So, if the signal is being handled in the context of a non-VM thread,
+// it means that the VM thread is running, and trying to sample its stack can
+// cause a crash.
+static inline bool IsVmThread() {
+  // In the case of a single VM thread, this check is enough.
+  if (pthread_equal(pthread_self(), vm_thread_)) return true;
+  // If there are multiple threads that use VM, they must have a thread id
+  // stored in TLS. To verify that the thread is really executing VM,
+  // we check Top's data. Having that ThreadManager::RestoreThread first
+  // restores ThreadLocalTop from TLS, and only then erases the TLS value,
+  // reading Top::thread_id() should not be affected by races.
+  if (ThreadManager::HasId() && !ThreadManager::IsArchived() &&
+      ThreadManager::CurrentId() == Top::thread_id()) {
+    return true;
+  }
+  return false;
+}
+
+
+static void ProfilerSignalHandler(int signal, siginfo_t* info, void* context) {
+#ifndef V8_HOST_ARCH_MIPS
+  USE(info);
+  if (signal != SIGPROF) return;
+  if (active_sampler_ == NULL) return;
+
+  TickSample sample_obj;
+  TickSample* sample = CpuProfiler::TickSampleEvent();
+  if (sample == NULL) sample = &sample_obj;
+
+  // We always sample the VM state.
+  sample->state = VMState::current_state();
+
+#if 0
+  // If profiling, we extract the current pc and sp.
+  if (active_sampler_->IsProfiling()) {
+    // Extracting the sample from the context is extremely machine dependent.
+    ucontext_t* ucontext = reinterpret_cast<ucontext_t*>(context);
+    mcontext_t& mcontext = ucontext->uc_mcontext;
+#if V8_HOST_ARCH_IA32
+    sample->pc = reinterpret_cast<Address>(mcontext.gregs[REG_EIP]);
+    sample->sp = reinterpret_cast<Address>(mcontext.gregs[REG_ESP]);
+    sample->fp = reinterpret_cast<Address>(mcontext.gregs[REG_EBP]);
+#elif V8_HOST_ARCH_X64
+    sample->pc = reinterpret_cast<Address>(mcontext.gregs[REG_RIP]);
+    sample->sp = reinterpret_cast<Address>(mcontext.gregs[REG_RSP]);
+    sample->fp = reinterpret_cast<Address>(mcontext.gregs[REG_RBP]);
+#elif V8_HOST_ARCH_ARM
+// An undefined macro evaluates to 0, so this applies to Android's Bionic also.
+#if (__GLIBC__ < 2 || (__GLIBC__ == 2 && __GLIBC_MINOR__ <= 3))
+    sample->pc = reinterpret_cast<Address>(mcontext.gregs[R15]);
+    sample->sp = reinterpret_cast<Address>(mcontext.gregs[R13]);
+    sample->fp = reinterpret_cast<Address>(mcontext.gregs[R11]);
+#else
+    sample->pc = reinterpret_cast<Address>(mcontext.arm_pc);
+    sample->sp = reinterpret_cast<Address>(mcontext.arm_sp);
+    sample->fp = reinterpret_cast<Address>(mcontext.arm_fp);
+#endif
+#elif V8_HOST_ARCH_MIPS
+    // Implement this on MIPS.
+    UNIMPLEMENTED();
+#endif
+    if (IsVmThread()) {
+      active_sampler_->SampleStack(sample);
+    }
+  }
+#endif
+
+  active_sampler_->Tick(sample);
+#endif
+}
+
+
+class Sampler::PlatformData : public Malloced {
+ public:
+  PlatformData() {
+    signal_handler_installed_ = false;
+  }
+
+  bool signal_handler_installed_;
+  struct sigaction old_signal_handler_;
+  struct itimerval old_timer_value_;
+};
+
+
+Sampler::Sampler(int interval, bool profiling)
+    : interval_(interval),
+      profiling_(profiling),
+      synchronous_(profiling),
+      active_(false) {
+  data_ = new PlatformData();
+}
+
+
+Sampler::~Sampler() {
+  delete data_;
+}
+
+
+void Sampler::Start() {
+  // There can only be one active sampler at the time on POSIX
+  // platforms.
+  if (active_sampler_ != NULL) return;
+
+  vm_thread_ = pthread_self();
+
+  // Request profiling signals.
+  struct sigaction sa;
+  sa.sa_sigaction = ProfilerSignalHandler;
+  sigemptyset(&sa.sa_mask);
+  sa.sa_flags = SA_SIGINFO;
+  if (sigaction(SIGPROF, &sa, &data_->old_signal_handler_) != 0) return;
+  data_->signal_handler_installed_ = true;
+
+  // Set the itimer to generate a tick for each interval.
+  itimerval itimer;
+  itimer.it_interval.tv_sec = interval_ / 1000;
+  itimer.it_interval.tv_usec = (interval_ % 1000) * 1000;
+  itimer.it_value.tv_sec = itimer.it_interval.tv_sec;
+  itimer.it_value.tv_usec = itimer.it_interval.tv_usec;
+  setitimer(ITIMER_PROF, &itimer, &data_->old_timer_value_);
+
+  // Set this sampler as the active sampler.
+  active_sampler_ = this;
+  active_ = true;
+}
+
+
+void Sampler::Stop() {
+  // Restore old signal handler
+  if (data_->signal_handler_installed_) {
+    setitimer(ITIMER_PROF, &data_->old_timer_value_, NULL);
+    sigaction(SIGPROF, &data_->old_signal_handler_, 0);
+    data_->signal_handler_installed_ = false;
+  }
+
+  // This sampler is no longer the active sampler.
+  active_sampler_ = NULL;
+  active_ = false;
+}
+
+
+#endif  // ENABLE_LOGGING_AND_PROFILING
+
+} }  // namespace v8::internal
diff --git a/src/platform.h b/src/platform.h
index 42e6eae..c4ef230 100644
--- a/src/platform.h
+++ b/src/platform.h
@@ -367,6 +367,7 @@ class ThreadHandle {
 
 class Thread: public ThreadHandle {
  public:
+#ifndef __CYGWIN__
   // Opaque data type for thread-local storage keys.
   // LOCAL_STORAGE_KEY_MIN_VALUE and LOCAL_STORAGE_KEY_MAX_VALUE are specified
   // to ensure that enumeration type has correct value range (see Issue 830 for
@@ -375,6 +376,10 @@ class Thread: public ThreadHandle {
     LOCAL_STORAGE_KEY_MIN_VALUE = kMinInt,
     LOCAL_STORAGE_KEY_MAX_VALUE = kMaxInt
   };
+#else
+  typedef void *LocalStorageKey;
+#endif
+
 
   // Create new thread.
   Thread();
diff --git a/src/utils.h b/src/utils.h
index ffdb639..0521767 100644
--- a/src/utils.h
+++ b/src/utils.h
@@ -963,7 +963,7 @@ inline Dest BitCast(const Source& source) {
 }
 
 template <class Dest, class Source>
-inline Dest BitCast(Source* source) {
+inline Dest BitCast(Source*& source) {
   return BitCast<Dest>(reinterpret_cast<uintptr_t>(source));
 }
 
diff --git a/tools/utils.py b/tools/utils.py
index 8083091..7733157 100644
--- a/tools/utils.py
+++ b/tools/utils.py
@@ -59,6 +59,8 @@ def GuessOS():
     return 'openbsd'
   elif id == 'SunOS':
     return 'solaris'
+  elif id.find('CYGWIN') >= 0:
+    return 'cygwin'
   else:
     return None
 
-- 
1.7.2

