xref: /openjdk10/hotspot/src/os/windows/vm/os_windows.cpp

/*
 * Copyright 1997-2010 Sun Microsystems, Inc.  All Rights Reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
 * CA 95054 USA or visit www.sun.com if you need additional information or
 * have any questions.
 *
 */

#ifdef _WIN64
// Must be at least Windows 2000 or XP to use VectoredExceptions
#define _WIN32_WINNT 0x500
#endif

// do not include precompiled header file
# include "incls/_os_windows.cpp.incl"

#ifdef _DEBUG
#include <crtdbg.h>
#endif


#include <windows.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/timeb.h>
#include <objidl.h>
#include <shlobj.h>

#include <malloc.h>
#include <signal.h>
#include <direct.h>
#include <errno.h>
#include <fcntl.h>
#include <io.h>
#include <process.h>              // For _beginthreadex(), _endthreadex()
#include <imagehlp.h>             // For os::dll_address_to_function_name

/* for enumerating dll libraries */
#include <tlhelp32.h>
#include <vdmdbg.h>

// for timer info max values which include all bits
#define ALL_64_BITS CONST64(0xFFFFFFFFFFFFFFFF)

// For DLL loading/load error detection
// Values of PE COFF
#define IMAGE_FILE_PTR_TO_SIGNATURE 0x3c
#define IMAGE_FILE_SIGNATURE_LENGTH 4

static HANDLE main_process;
static HANDLE main_thread;
static int    main_thread_id;

static FILETIME process_creation_time;
static FILETIME process_exit_time;
static FILETIME process_user_time;
static FILETIME process_kernel_time;

#ifdef _WIN64
PVOID  topLevelVectoredExceptionHandler = NULL;
#endif

#ifdef _M_IA64
#define __CPU__ ia64
#elif _M_AMD64
#define __CPU__ amd64
#else
#define __CPU__ i486
#endif

// save DLL module handle, used by GetModuleFileName

HINSTANCE vm_lib_handle;
static int getLastErrorString(char *buf, size_t len);

BOOL WINAPI DllMain(HINSTANCE hinst, DWORD reason, LPVOID reserved) {
  switch (reason) {
    case DLL_PROCESS_ATTACH:
      vm_lib_handle = hinst;
      if(ForceTimeHighResolution)
        timeBeginPeriod(1L);
      break;
    case DLL_PROCESS_DETACH:
      if(ForceTimeHighResolution)
        timeEndPeriod(1L);
#ifdef _WIN64
      if (topLevelVectoredExceptionHandler != NULL) {
        RemoveVectoredExceptionHandler(topLevelVectoredExceptionHandler);
        topLevelVectoredExceptionHandler = NULL;
      }
#endif
      break;
    default:
      break;
  }
  return true;
}

static inline double fileTimeAsDouble(FILETIME* time) {
  const double high  = (double) ((unsigned int) ~0);
  const double split = 10000000.0;
  double result = (time->dwLowDateTime / split) +
                   time->dwHighDateTime * (high/split);
  return result;
}

// Implementation of os

bool os::getenv(const char* name, char* buffer, int len) {
 int result = GetEnvironmentVariable(name, buffer, len);
 return result > 0 && result < len;
}


// No setuid programs under Windows.
bool os::have_special_privileges() {
  return false;
}


// This method is  a periodic task to check for misbehaving JNI applications
// under CheckJNI, we can add any periodic checks here.
// For Windows at the moment does nothing
void os::run_periodic_checks() {
  return;
}

#ifndef _WIN64
// previous UnhandledExceptionFilter, if there is one
static LPTOP_LEVEL_EXCEPTION_FILTER prev_uef_handler = NULL;

LONG WINAPI Handle_FLT_Exception(struct _EXCEPTION_POINTERS* exceptionInfo);
#endif
void os::init_system_properties_values() {
  /* sysclasspath, java_home, dll_dir */
  {
      char *home_path;
      char *dll_path;
      char *pslash;
      char *bin = "\\bin";
      char home_dir[MAX_PATH];

      if (!getenv("_ALT_JAVA_HOME_DIR", home_dir, MAX_PATH)) {
          os::jvm_path(home_dir, sizeof(home_dir));
          // Found the full path to jvm[_g].dll.
          // Now cut the path to <java_home>/jre if we can.
          *(strrchr(home_dir, '\\')) = '\0';  /* get rid of \jvm.dll */
          pslash = strrchr(home_dir, '\\');
          if (pslash != NULL) {
              *pslash = '\0';                 /* get rid of \{client|server} */
              pslash = strrchr(home_dir, '\\');
              if (pslash != NULL)
                  *pslash = '\0';             /* get rid of \bin */
          }
      }

      home_path = NEW_C_HEAP_ARRAY(char, strlen(home_dir) + 1);
      if (home_path == NULL)
          return;
      strcpy(home_path, home_dir);
      Arguments::set_java_home(home_path);

      dll_path = NEW_C_HEAP_ARRAY(char, strlen(home_dir) + strlen(bin) + 1);
      if (dll_path == NULL)
          return;
      strcpy(dll_path, home_dir);
      strcat(dll_path, bin);
      Arguments::set_dll_dir(dll_path);

      if (!set_boot_path('\\', ';'))
          return;
  }

  /* library_path */
  #define EXT_DIR "\\lib\\ext"
  #define BIN_DIR "\\bin"
  #define PACKAGE_DIR "\\Sun\\Java"
  {
    /* Win32 library search order (See the documentation for LoadLibrary):
     *
     * 1. The directory from which application is loaded.
     * 2. The current directory
     * 3. The system wide Java Extensions directory (Java only)
     * 4. System directory (GetSystemDirectory)
     * 5. Windows directory (GetWindowsDirectory)
     * 6. The PATH environment variable
     */

    char *library_path;
    char tmp[MAX_PATH];
    char *path_str = ::getenv("PATH");

    library_path = NEW_C_HEAP_ARRAY(char, MAX_PATH * 5 + sizeof(PACKAGE_DIR) +
        sizeof(BIN_DIR) + (path_str ? strlen(path_str) : 0) + 10);

    library_path[0] = '\0';

    GetModuleFileName(NULL, tmp, sizeof(tmp));
    *(strrchr(tmp, '\\')) = '\0';
    strcat(library_path, tmp);

    strcat(library_path, ";.");

    GetWindowsDirectory(tmp, sizeof(tmp));
    strcat(library_path, ";");
    strcat(library_path, tmp);
    strcat(library_path, PACKAGE_DIR BIN_DIR);

    GetSystemDirectory(tmp, sizeof(tmp));
    strcat(library_path, ";");
    strcat(library_path, tmp);

    GetWindowsDirectory(tmp, sizeof(tmp));
    strcat(library_path, ";");
    strcat(library_path, tmp);

    if (path_str) {
        strcat(library_path, ";");
        strcat(library_path, path_str);
    }

    Arguments::set_library_path(library_path);
    FREE_C_HEAP_ARRAY(char, library_path);
  }

  /* Default extensions directory */
  {
    char path[MAX_PATH];
    char buf[2 * MAX_PATH + 2 * sizeof(EXT_DIR) + sizeof(PACKAGE_DIR) + 1];
    GetWindowsDirectory(path, MAX_PATH);
    sprintf(buf, "%s%s;%s%s%s", Arguments::get_java_home(), EXT_DIR,
        path, PACKAGE_DIR, EXT_DIR);
    Arguments::set_ext_dirs(buf);
  }
  #undef EXT_DIR
  #undef BIN_DIR
  #undef PACKAGE_DIR

  /* Default endorsed standards directory. */
  {
    #define ENDORSED_DIR "\\lib\\endorsed"
    size_t len = strlen(Arguments::get_java_home()) + sizeof(ENDORSED_DIR);
    char * buf = NEW_C_HEAP_ARRAY(char, len);
    sprintf(buf, "%s%s", Arguments::get_java_home(), ENDORSED_DIR);
    Arguments::set_endorsed_dirs(buf);
    #undef ENDORSED_DIR
  }

#ifndef _WIN64
  // set our UnhandledExceptionFilter and save any previous one
  prev_uef_handler = SetUnhandledExceptionFilter(Handle_FLT_Exception);
#endif

  // Done
  return;
}

void os::breakpoint() {
  DebugBreak();
}

// Invoked from the BREAKPOINT Macro
extern "C" void breakpoint() {
  os::breakpoint();
}

// Returns an estimate of the current stack pointer. Result must be guaranteed
// to point into the calling threads stack, and be no lower than the current
// stack pointer.

address os::current_stack_pointer() {
  int dummy;
  address sp = (address)&dummy;
  return sp;
}

// os::current_stack_base()
//
//   Returns the base of the stack, which is the stack's
//   starting address.  This function must be called
//   while running on the stack of the thread being queried.

address os::current_stack_base() {
  MEMORY_BASIC_INFORMATION minfo;
  address stack_bottom;
  size_t stack_size;

  VirtualQuery(&minfo, &minfo, sizeof(minfo));
  stack_bottom =  (address)minfo.AllocationBase;
  stack_size = minfo.RegionSize;

  // Add up the sizes of all the regions with the same
  // AllocationBase.
  while( 1 )
  {
    VirtualQuery(stack_bottom+stack_size, &minfo, sizeof(minfo));
    if ( stack_bottom == (address)minfo.AllocationBase )
      stack_size += minfo.RegionSize;
    else
      break;
  }

#ifdef _M_IA64
  // IA64 has memory and register stacks
  stack_size = stack_size / 2;
#endif
  return stack_bottom + stack_size;
}

size_t os::current_stack_size() {
  size_t sz;
  MEMORY_BASIC_INFORMATION minfo;
  VirtualQuery(&minfo, &minfo, sizeof(minfo));
  sz = (size_t)os::current_stack_base() - (size_t)minfo.AllocationBase;
  return sz;
}


LONG WINAPI topLevelExceptionFilter(struct _EXCEPTION_POINTERS* exceptionInfo);

// Thread start routine for all new Java threads
static unsigned __stdcall java_start(Thread* thread) {
  // Try to randomize the cache line index of hot stack frames.
  // This helps when threads of the same stack traces evict each other's
  // cache lines. The threads can be either from the same JVM instance, or
  // from different JVM instances. The benefit is especially true for
  // processors with hyperthreading technology.
  static int counter = 0;
  int pid = os::current_process_id();
  _alloca(((pid ^ counter++) & 7) * 128);

  OSThread* osthr = thread->osthread();
  assert(osthr->get_state() == RUNNABLE, "invalid os thread state");

  if (UseNUMA) {
    int lgrp_id = os::numa_get_group_id();
    if (lgrp_id != -1) {
      thread->set_lgrp_id(lgrp_id);
    }
  }


  if (UseVectoredExceptions) {
    // If we are using vectored exception we don't need to set a SEH
    thread->run();
  }
  else {
    // Install a win32 structured exception handler around every thread created
    // by VM, so VM can genrate error dump when an exception occurred in non-
    // Java thread (e.g. VM thread).
    __try {
       thread->run();
    } __except(topLevelExceptionFilter(
               (_EXCEPTION_POINTERS*)_exception_info())) {
        // Nothing to do.
    }
  }

  // One less thread is executing
  // When the VMThread gets here, the main thread may have already exited
  // which frees the CodeHeap containing the Atomic::add code
  if (thread != VMThread::vm_thread() && VMThread::vm_thread() != NULL) {
    Atomic::dec_ptr((intptr_t*)&os::win32::_os_thread_count);
  }

  return 0;
}

static OSThread* create_os_thread(Thread* thread, HANDLE thread_handle, int thread_id) {
  // Allocate the OSThread object
  OSThread* osthread = new OSThread(NULL, NULL);
  if (osthread == NULL) return NULL;

  // Initialize support for Java interrupts
  HANDLE interrupt_event = CreateEvent(NULL, true, false, NULL);
  if (interrupt_event == NULL) {
    delete osthread;
    return NULL;
  }
  osthread->set_interrupt_event(interrupt_event);

  // Store info on the Win32 thread into the OSThread
  osthread->set_thread_handle(thread_handle);
  osthread->set_thread_id(thread_id);

  if (UseNUMA) {
    int lgrp_id = os::numa_get_group_id();
    if (lgrp_id != -1) {
      thread->set_lgrp_id(lgrp_id);
    }
  }

  // Initial thread state is INITIALIZED, not SUSPENDED
  osthread->set_state(INITIALIZED);

  return osthread;
}


bool os::create_attached_thread(JavaThread* thread) {
#ifdef ASSERT
  thread->verify_not_published();
#endif
  HANDLE thread_h;
  if (!DuplicateHandle(main_process, GetCurrentThread(), GetCurrentProcess(),
                       &thread_h, THREAD_ALL_ACCESS, false, 0)) {
    fatal("DuplicateHandle failed\n");
  }
  OSThread* osthread = create_os_thread(thread, thread_h,
                                        (int)current_thread_id());
  if (osthread == NULL) {
     return false;
  }

  // Initial thread state is RUNNABLE
  osthread->set_state(RUNNABLE);

  thread->set_osthread(osthread);
  return true;
}

bool os::create_main_thread(JavaThread* thread) {
#ifdef ASSERT
  thread->verify_not_published();
#endif
  if (_starting_thread == NULL) {
    _starting_thread = create_os_thread(thread, main_thread, main_thread_id);
     if (_starting_thread == NULL) {
        return false;
     }
  }

  // The primordial thread is runnable from the start)
  _starting_thread->set_state(RUNNABLE);

  thread->set_osthread(_starting_thread);
  return true;
}

// Allocate and initialize a new OSThread
bool os::create_thread(Thread* thread, ThreadType thr_type, size_t stack_size) {
  unsigned thread_id;

  // Allocate the OSThread object
  OSThread* osthread = new OSThread(NULL, NULL);
  if (osthread == NULL) {
    return false;
  }

  // Initialize support for Java interrupts
  HANDLE interrupt_event = CreateEvent(NULL, true, false, NULL);
  if (interrupt_event == NULL) {
    delete osthread;
    return NULL;
  }
  osthread->set_interrupt_event(interrupt_event);
  osthread->set_interrupted(false);

  thread->set_osthread(osthread);

  if (stack_size == 0) {
    switch (thr_type) {
    case os::java_thread:
      // Java threads use ThreadStackSize which default value can be changed with the flag -Xss
      if (JavaThread::stack_size_at_create() > 0)
        stack_size = JavaThread::stack_size_at_create();
      break;
    case os::compiler_thread:
      if (CompilerThreadStackSize > 0) {
        stack_size = (size_t)(CompilerThreadStackSize * K);
        break;
      } // else fall through:
        // use VMThreadStackSize if CompilerThreadStackSize is not defined
    case os::vm_thread:
    case os::pgc_thread:
    case os::cgc_thread:
    case os::watcher_thread:
      if (VMThreadStackSize > 0) stack_size = (size_t)(VMThreadStackSize * K);
      break;
    }
  }

  // Create the Win32 thread
  //
  // Contrary to what MSDN document says, "stack_size" in _beginthreadex()
  // does not specify stack size. Instead, it specifies the size of
  // initially committed space. The stack size is determined by
  // PE header in the executable. If the committed "stack_size" is larger
  // than default value in the PE header, the stack is rounded up to the
  // nearest multiple of 1MB. For example if the launcher has default
  // stack size of 320k, specifying any size less than 320k does not
  // affect the actual stack size at all, it only affects the initial
  // commitment. On the other hand, specifying 'stack_size' larger than
  // default value may cause significant increase in memory usage, because
  // not only the stack space will be rounded up to MB, but also the
  // entire space is committed upfront.
  //
  // Finally Windows XP added a new flag 'STACK_SIZE_PARAM_IS_A_RESERVATION'
  // for CreateThread() that can treat 'stack_size' as stack size. However we
  // are not supposed to call CreateThread() directly according to MSDN
  // document because JVM uses C runtime library. The good news is that the
  // flag appears to work with _beginthredex() as well.

#ifndef STACK_SIZE_PARAM_IS_A_RESERVATION
#define STACK_SIZE_PARAM_IS_A_RESERVATION  (0x10000)
#endif

  HANDLE thread_handle =
    (HANDLE)_beginthreadex(NULL,
                           (unsigned)stack_size,
                           (unsigned (__stdcall *)(void*)) java_start,
                           thread,
                           CREATE_SUSPENDED | STACK_SIZE_PARAM_IS_A_RESERVATION,
                           &thread_id);
  if (thread_handle == NULL) {
    // perhaps STACK_SIZE_PARAM_IS_A_RESERVATION is not supported, try again
    // without the flag.
    thread_handle =
    (HANDLE)_beginthreadex(NULL,
                           (unsigned)stack_size,
                           (unsigned (__stdcall *)(void*)) java_start,
                           thread,
                           CREATE_SUSPENDED,
                           &thread_id);
  }
  if (thread_handle == NULL) {
    // Need to clean up stuff we've allocated so far
    CloseHandle(osthread->interrupt_event());
    thread->set_osthread(NULL);
    delete osthread;
    return NULL;
  }

  Atomic::inc_ptr((intptr_t*)&os::win32::_os_thread_count);

  // Store info on the Win32 thread into the OSThread
  osthread->set_thread_handle(thread_handle);
  osthread->set_thread_id(thread_id);

  // Initial thread state is INITIALIZED, not SUSPENDED
  osthread->set_state(INITIALIZED);

  // The thread is returned suspended (in state INITIALIZED), and is started higher up in the call chain
  return true;
}


// Free Win32 resources related to the OSThread
void os::free_thread(OSThread* osthread) {
  assert(osthread != NULL, "osthread not set");
  CloseHandle(osthread->thread_handle());
  CloseHandle(osthread->interrupt_event());
  delete osthread;
}


static int    has_performance_count = 0;
static jlong first_filetime;
static jlong initial_performance_count;
static jlong performance_frequency;


jlong as_long(LARGE_INTEGER x) {
  jlong result = 0; // initialization to avoid warning
  set_high(&result, x.HighPart);
  set_low(&result,  x.LowPart);
  return result;
}


jlong os::elapsed_counter() {
  LARGE_INTEGER count;
  if (has_performance_count) {
    QueryPerformanceCounter(&count);
    return as_long(count) - initial_performance_count;
  } else {
    FILETIME wt;
    GetSystemTimeAsFileTime(&wt);
    return (jlong_from(wt.dwHighDateTime, wt.dwLowDateTime) - first_filetime);
  }
}


jlong os::elapsed_frequency() {
  if (has_performance_count) {
    return performance_frequency;
  } else {
   // the FILETIME time is the number of 100-nanosecond intervals since January 1,1601.
   return 10000000;
  }
}


julong os::available_memory() {
  return win32::available_memory();
}

julong os::win32::available_memory() {
  // FIXME: GlobalMemoryStatus() may return incorrect value if total memory
  // is larger than 4GB
  MEMORYSTATUS ms;
  GlobalMemoryStatus(&ms);

  return (julong)ms.dwAvailPhys;
}

julong os::physical_memory() {
  return win32::physical_memory();
}

julong os::allocatable_physical_memory(julong size) {
#ifdef _LP64
  return size;
#else
  // Limit to 1400m because of the 2gb address space wall
  return MIN2(size, (julong)1400*M);
#endif
}

// VC6 lacks DWORD_PTR
#if _MSC_VER < 1300
typedef UINT_PTR DWORD_PTR;
#endif

int os::active_processor_count() {
  DWORD_PTR lpProcessAffinityMask = 0;
  DWORD_PTR lpSystemAffinityMask = 0;
  int proc_count = processor_count();
  if (proc_count <= sizeof(UINT_PTR) * BitsPerByte &&
      GetProcessAffinityMask(GetCurrentProcess(), &lpProcessAffinityMask, &lpSystemAffinityMask)) {
    // Nof active processors is number of bits in process affinity mask
    int bitcount = 0;
    while (lpProcessAffinityMask != 0) {
      lpProcessAffinityMask = lpProcessAffinityMask & (lpProcessAffinityMask-1);
      bitcount++;
    }
    return bitcount;
  } else {
    return proc_count;
  }
}

bool os::distribute_processes(uint length, uint* distribution) {
  // Not yet implemented.
  return false;
}

bool os::bind_to_processor(uint processor_id) {
  // Not yet implemented.
  return false;
}

static void initialize_performance_counter() {
  LARGE_INTEGER count;
  if (QueryPerformanceFrequency(&count)) {
    has_performance_count = 1;
    performance_frequency = as_long(count);
    QueryPerformanceCounter(&count);
    initial_performance_count = as_long(count);
  } else {
    has_performance_count = 0;
    FILETIME wt;
    GetSystemTimeAsFileTime(&wt);
    first_filetime = jlong_from(wt.dwHighDateTime, wt.dwLowDateTime);
  }
}


double os::elapsedTime() {
  return (double) elapsed_counter() / (double) elapsed_frequency();
}


// Windows format:
//   The FILETIME structure is a 64-bit value representing the number of 100-nanosecond intervals since January 1, 1601.
// Java format:
//   Java standards require the number of milliseconds since 1/1/1970

// Constant offset - calculated using offset()
static jlong  _offset   = 116444736000000000;
// Fake time counter for reproducible results when debugging
static jlong  fake_time = 0;

#ifdef ASSERT
// Just to be safe, recalculate the offset in debug mode
static jlong _calculated_offset = 0;
static int   _has_calculated_offset = 0;

jlong offset() {
  if (_has_calculated_offset) return _calculated_offset;
  SYSTEMTIME java_origin;
  java_origin.wYear          = 1970;
  java_origin.wMonth         = 1;
  java_origin.wDayOfWeek     = 0; // ignored
  java_origin.wDay           = 1;
  java_origin.wHour          = 0;
  java_origin.wMinute        = 0;
  java_origin.wSecond        = 0;
  java_origin.wMilliseconds  = 0;
  FILETIME jot;
  if (!SystemTimeToFileTime(&java_origin, &jot)) {
    fatal1("Error = %d\nWindows error", GetLastError());
  }
  _calculated_offset = jlong_from(jot.dwHighDateTime, jot.dwLowDateTime);
  _has_calculated_offset = 1;
  assert(_calculated_offset == _offset, "Calculated and constant time offsets must be equal");
  return _calculated_offset;
}
#else
jlong offset() {
  return _offset;
}
#endif

jlong windows_to_java_time(FILETIME wt) {
  jlong a = jlong_from(wt.dwHighDateTime, wt.dwLowDateTime);
  return (a - offset()) / 10000;
}

FILETIME java_to_windows_time(jlong l) {
  jlong a = (l * 10000) + offset();
  FILETIME result;
  result.dwHighDateTime = high(a);
  result.dwLowDateTime  = low(a);
  return result;
}

// For now, we say that Windows does not support vtime.  I have no idea
// whether it can actually be made to (DLD, 9/13/05).

bool os::supports_vtime() { return false; }
bool os::enable_vtime() { return false; }
bool os::vtime_enabled() { return false; }
double os::elapsedVTime() {
  // better than nothing, but not much
  return elapsedTime();
}

jlong os::javaTimeMillis() {
  if (UseFakeTimers) {
    return fake_time++;
  } else {
    FILETIME wt;
    GetSystemTimeAsFileTime(&wt);
    return windows_to_java_time(wt);
  }
}

#define NANOS_PER_SEC         CONST64(1000000000)
#define NANOS_PER_MILLISEC    1000000
jlong os::javaTimeNanos() {
  if (!has_performance_count) {
    return javaTimeMillis() * NANOS_PER_MILLISEC; // the best we can do.
  } else {
    LARGE_INTEGER current_count;
    QueryPerformanceCounter(&current_count);
    double current = as_long(current_count);
    double freq = performance_frequency;
    jlong time = (jlong)((current/freq) * NANOS_PER_SEC);
    return time;
  }
}

void os::javaTimeNanos_info(jvmtiTimerInfo *info_ptr) {
  if (!has_performance_count) {
    // javaTimeMillis() doesn't have much percision,
    // but it is not going to wrap -- so all 64 bits
    info_ptr->max_value = ALL_64_BITS;

    // this is a wall clock timer, so may skip
    info_ptr->may_skip_backward = true;
    info_ptr->may_skip_forward = true;
  } else {
    jlong freq = performance_frequency;
    if (freq < NANOS_PER_SEC) {
      // the performance counter is 64 bits and we will
      // be multiplying it -- so no wrap in 64 bits
      info_ptr->max_value = ALL_64_BITS;
    } else if (freq > NANOS_PER_SEC) {
      // use the max value the counter can reach to
      // determine the max value which could be returned
      julong max_counter = (julong)ALL_64_BITS;
      info_ptr->max_value = (jlong)(max_counter / (freq / NANOS_PER_SEC));
    } else {
      // the performance counter is 64 bits and we will
      // be using it directly -- so no wrap in 64 bits
      info_ptr->max_value = ALL_64_BITS;
    }

    // using a counter, so no skipping
    info_ptr->may_skip_backward = false;
    info_ptr->may_skip_forward = false;
  }
  info_ptr->kind = JVMTI_TIMER_ELAPSED;                // elapsed not CPU time
}

char* os::local_time_string(char *buf, size_t buflen) {
  SYSTEMTIME st;
  GetLocalTime(&st);
  jio_snprintf(buf, buflen, "%d-%02d-%02d %02d:%02d:%02d",
               st.wYear, st.wMonth, st.wDay, st.wHour, st.wMinute, st.wSecond);
  return buf;
}

bool os::getTimesSecs(double* process_real_time,
                     double* process_user_time,
                     double* process_system_time) {
  HANDLE h_process = GetCurrentProcess();
  FILETIME create_time, exit_time, kernel_time, user_time;
  BOOL result = GetProcessTimes(h_process,
                               &create_time,
                               &exit_time,
                               &kernel_time,
                               &user_time);
  if (result != 0) {
    FILETIME wt;
    GetSystemTimeAsFileTime(&wt);
    jlong rtc_millis = windows_to_java_time(wt);
    jlong user_millis = windows_to_java_time(user_time);
    jlong system_millis = windows_to_java_time(kernel_time);
    *process_real_time = ((double) rtc_millis) / ((double) MILLIUNITS);
    *process_user_time = ((double) user_millis) / ((double) MILLIUNITS);
    *process_system_time = ((double) system_millis) / ((double) MILLIUNITS);
    return true;
  } else {
    return false;
  }
}

void os::shutdown() {

  // allow PerfMemory to attempt cleanup of any persistent resources
  perfMemory_exit();

  // flush buffered output, finish log files
  ostream_abort();

  // Check for abort hook
  abort_hook_t abort_hook = Arguments::abort_hook();
  if (abort_hook != NULL) {
    abort_hook();
  }
}

void os::abort(bool dump_core)
{
  os::shutdown();
  // no core dump on Windows
  ::exit(1);
}

// Die immediately, no exit hook, no abort hook, no cleanup.
void os::die() {
  _exit(-1);
}

// Directory routines copied from src/win32/native/java/io/dirent_md.c
//  * dirent_md.c       1.15 00/02/02
//
// The declarations for DIR and struct dirent are in jvm_win32.h.

/* Caller must have already run dirname through JVM_NativePath, which removes
   duplicate slashes and converts all instances of '/' into '\\'. */

DIR *
os::opendir(const char *dirname)
{
    assert(dirname != NULL, "just checking");   // hotspot change
    DIR *dirp = (DIR *)malloc(sizeof(DIR));
    DWORD fattr;                                // hotspot change
    char alt_dirname[4] = { 0, 0, 0, 0 };

    if (dirp == 0) {
        errno = ENOMEM;
        return 0;
    }

    /*
     * Win32 accepts "\" in its POSIX stat(), but refuses to treat it
     * as a directory in FindFirstFile().  We detect this case here and
     * prepend the current drive name.
     */
    if (dirname[1] == '\0' && dirname[0] == '\\') {
        alt_dirname[0] = _getdrive() + 'A' - 1;
        alt_dirname[1] = ':';
        alt_dirname[2] = '\\';
        alt_dirname[3] = '\0';
        dirname = alt_dirname;
    }

    dirp->path = (char *)malloc(strlen(dirname) + 5);
    if (dirp->path == 0) {
        free(dirp);
        errno = ENOMEM;
        return 0;
    }
    strcpy(dirp->path, dirname);

    fattr = GetFileAttributes(dirp->path);
    if (fattr == 0xffffffff) {
        free(dirp->path);
        free(dirp);
        errno = ENOENT;
        return 0;
    } else if ((fattr & FILE_ATTRIBUTE_DIRECTORY) == 0) {
        free(dirp->path);
        free(dirp);
        errno = ENOTDIR;
        return 0;
    }

    /* Append "*.*", or possibly "\\*.*", to path */
    if (dirp->path[1] == ':'
        && (dirp->path[2] == '\0'
            || (dirp->path[2] == '\\' && dirp->path[3] == '\0'))) {
        /* No '\\' needed for cases like "Z:" or "Z:\" */
        strcat(dirp->path, "*.*");
    } else {
        strcat(dirp->path, "\\*.*");
    }

    dirp->handle = FindFirstFile(dirp->path, &dirp->find_data);
    if (dirp->handle == INVALID_HANDLE_VALUE) {
        if (GetLastError() != ERROR_FILE_NOT_FOUND) {
            free(dirp->path);
            free(dirp);
            errno = EACCES;
            return 0;
        }
    }
    return dirp;
}

/* parameter dbuf unused on Windows */

struct dirent *
os::readdir(DIR *dirp, dirent *dbuf)
{
    assert(dirp != NULL, "just checking");      // hotspot change
    if (dirp->handle == INVALID_HANDLE_VALUE) {
        return 0;
    }

    strcpy(dirp->dirent.d_name, dirp->find_data.cFileName);

    if (!FindNextFile(dirp->handle, &dirp->find_data)) {
        if (GetLastError() == ERROR_INVALID_HANDLE) {
            errno = EBADF;
            return 0;
        }
        FindClose(dirp->handle);
        dirp->handle = INVALID_HANDLE_VALUE;
    }

    return &dirp->dirent;
}

int
os::closedir(DIR *dirp)
{
    assert(dirp != NULL, "just checking");      // hotspot change
    if (dirp->handle != INVALID_HANDLE_VALUE) {
        if (!FindClose(dirp->handle)) {
            errno = EBADF;
            return -1;
        }
        dirp->handle = INVALID_HANDLE_VALUE;
    }
    free(dirp->path);
    free(dirp);
    return 0;
}

const char* os::dll_file_extension() { return ".dll"; }

const char * os::get_temp_directory()
{
    static char path_buf[MAX_PATH];
    if (GetTempPath(MAX_PATH, path_buf)>0)
      return path_buf;
    else{
      path_buf[0]='\0';
      return path_buf;
    }
}

void os::dll_build_name(char *holder, size_t holderlen,
                        const char* pname, const char* fname)
{
    // copied from libhpi
    const size_t pnamelen = pname ? strlen(pname) : 0;
    const char c = (pnamelen > 0) ? pname[pnamelen-1] : 0;

    /* Quietly truncates on buffer overflow. Should be an error. */
    if (pnamelen + strlen(fname) + 10 > holderlen) {
        *holder = '\0';
        return;
    }

    if (pnamelen == 0) {
        sprintf(holder, "%s.dll", fname);
    } else if (c == ':' || c == '\\') {
        sprintf(holder, "%s%s.dll", pname, fname);
    } else {
        sprintf(holder, "%s\\%s.dll", pname, fname);
    }
}

// Needs to be in os specific directory because windows requires another
// header file <direct.h>
const char* os::get_current_directory(char *buf, int buflen) {
  return _getcwd(buf, buflen);
}

//-----------------------------------------------------------
// Helper functions for fatal error handler

// The following library functions are resolved dynamically at runtime:

// PSAPI functions, for Windows NT, 2000, XP

// psapi.h doesn't come with Visual Studio 6; it can be downloaded as Platform
// SDK from Microsoft.  Here are the definitions copied from psapi.h
typedef struct _MODULEINFO {
    LPVOID lpBaseOfDll;
    DWORD SizeOfImage;
    LPVOID EntryPoint;
} MODULEINFO, *LPMODULEINFO;

static BOOL  (WINAPI *_EnumProcessModules)  ( HANDLE, HMODULE *, DWORD, LPDWORD );
static DWORD (WINAPI *_GetModuleFileNameEx) ( HANDLE, HMODULE, LPTSTR, DWORD );
static BOOL  (WINAPI *_GetModuleInformation)( HANDLE, HMODULE, LPMODULEINFO, DWORD );

// ToolHelp Functions, for Windows 95, 98 and ME

static HANDLE(WINAPI *_CreateToolhelp32Snapshot)(DWORD,DWORD) ;
static BOOL  (WINAPI *_Module32First)           (HANDLE,LPMODULEENTRY32) ;
static BOOL  (WINAPI *_Module32Next)            (HANDLE,LPMODULEENTRY32) ;

bool _has_psapi;
bool _psapi_init = false;
bool _has_toolhelp;

static bool _init_psapi() {
  HINSTANCE psapi = LoadLibrary( "PSAPI.DLL" ) ;
  if( psapi == NULL ) return false ;

  _EnumProcessModules = CAST_TO_FN_PTR(
      BOOL(WINAPI *)(HANDLE, HMODULE *, DWORD, LPDWORD),
      GetProcAddress(psapi, "EnumProcessModules")) ;
  _GetModuleFileNameEx = CAST_TO_FN_PTR(
      DWORD (WINAPI *)(HANDLE, HMODULE, LPTSTR, DWORD),
      GetProcAddress(psapi, "GetModuleFileNameExA"));
  _GetModuleInformation = CAST_TO_FN_PTR(
      BOOL (WINAPI *)(HANDLE, HMODULE, LPMODULEINFO, DWORD),
      GetProcAddress(psapi, "GetModuleInformation"));

  _has_psapi = (_EnumProcessModules && _GetModuleFileNameEx && _GetModuleInformation);
  _psapi_init = true;
  return _has_psapi;
}

static bool _init_toolhelp() {
  HINSTANCE kernel32 = LoadLibrary("Kernel32.DLL") ;
  if (kernel32 == NULL) return false ;

  _CreateToolhelp32Snapshot = CAST_TO_FN_PTR(
      HANDLE(WINAPI *)(DWORD,DWORD),
      GetProcAddress(kernel32, "CreateToolhelp32Snapshot"));
  _Module32First = CAST_TO_FN_PTR(
      BOOL(WINAPI *)(HANDLE,LPMODULEENTRY32),
      GetProcAddress(kernel32, "Module32First" ));
  _Module32Next = CAST_TO_FN_PTR(
      BOOL(WINAPI *)(HANDLE,LPMODULEENTRY32),
      GetProcAddress(kernel32, "Module32Next" ));

  _has_toolhelp = (_CreateToolhelp32Snapshot && _Module32First && _Module32Next);
  return _has_toolhelp;
}

#ifdef _WIN64
// Helper routine which returns true if address in
// within the NTDLL address space.
//
static bool _addr_in_ntdll( address addr )
{
  HMODULE hmod;
  MODULEINFO minfo;

  hmod = GetModuleHandle("NTDLL.DLL");
  if ( hmod == NULL ) return false;
  if ( !_GetModuleInformation( GetCurrentProcess(), hmod,
                               &minfo, sizeof(MODULEINFO)) )
    return false;

  if ( (addr >= minfo.lpBaseOfDll) &&
       (addr < (address)((uintptr_t)minfo.lpBaseOfDll + (uintptr_t)minfo.SizeOfImage)))
    return true;
  else
    return false;
}
#endif


// Enumerate all modules for a given process ID
//
// Notice that Windows 95/98/Me and Windows NT/2000/XP have
// different API for doing this. We use PSAPI.DLL on NT based
// Windows and ToolHelp on 95/98/Me.

// Callback function that is called by enumerate_modules() on
// every DLL module.
// Input parameters:
//    int       pid,
//    char*     module_file_name,
//    address   module_base_addr,
//    unsigned  module_size,
//    void*     param
typedef int (*EnumModulesCallbackFunc)(int, char *, address, unsigned, void *);

// enumerate_modules for Windows NT, using PSAPI
static int _enumerate_modules_winnt( int pid, EnumModulesCallbackFunc func, void * param)
{
  HANDLE   hProcess ;

# define MAX_NUM_MODULES 128
  HMODULE     modules[MAX_NUM_MODULES];
  static char filename[ MAX_PATH ];
  int         result = 0;

  if (!_has_psapi && (_psapi_init || !_init_psapi())) return 0;

  hProcess = OpenProcess(PROCESS_QUERY_INFORMATION | PROCESS_VM_READ,
                         FALSE, pid ) ;
  if (hProcess == NULL) return 0;

  DWORD size_needed;
  if (!_EnumProcessModules(hProcess, modules,
                           sizeof(modules), &size_needed)) {
      CloseHandle( hProcess );
      return 0;
  }

  // number of modules that are currently loaded
  int num_modules = size_needed / sizeof(HMODULE);

  for (int i = 0; i < MIN2(num_modules, MAX_NUM_MODULES); i++) {
    // Get Full pathname:
    if(!_GetModuleFileNameEx(hProcess, modules[i],
                             filename, sizeof(filename))) {
        filename[0] = '\0';
    }

    MODULEINFO modinfo;
    if (!_GetModuleInformation(hProcess, modules[i],
                               &modinfo, sizeof(modinfo))) {
        modinfo.lpBaseOfDll = NULL;
        modinfo.SizeOfImage = 0;
    }

    // Invoke callback function
    result = func(pid, filename, (address)modinfo.lpBaseOfDll,
                  modinfo.SizeOfImage, param);
    if (result) break;
  }

  CloseHandle( hProcess ) ;
  return result;
}


// enumerate_modules for Windows 95/98/ME, using TOOLHELP
static int _enumerate_modules_windows( int pid, EnumModulesCallbackFunc func, void *param)
{
  HANDLE                hSnapShot ;
  static MODULEENTRY32  modentry ;
  int                   result = 0;

  if (!_has_toolhelp) return 0;

  // Get a handle to a Toolhelp snapshot of the system
  hSnapShot = _CreateToolhelp32Snapshot(TH32CS_SNAPMODULE, pid ) ;
  if( hSnapShot == INVALID_HANDLE_VALUE ) {
      return FALSE ;
  }

  // iterate through all modules
  modentry.dwSize = sizeof(MODULEENTRY32) ;
  bool not_done = _Module32First( hSnapShot, &modentry ) != 0;

  while( not_done ) {
    // invoke the callback
    result=func(pid, modentry.szExePath, (address)modentry.modBaseAddr,
                modentry.modBaseSize, param);
    if (result) break;

    modentry.dwSize = sizeof(MODULEENTRY32) ;
    not_done = _Module32Next( hSnapShot, &modentry ) != 0;
  }

  CloseHandle(hSnapShot);
  return result;
}

int enumerate_modules( int pid, EnumModulesCallbackFunc func, void * param )
{
  // Get current process ID if caller doesn't provide it.
  if (!pid) pid = os::current_process_id();

  if (os::win32::is_nt()) return _enumerate_modules_winnt  (pid, func, param);
  else                    return _enumerate_modules_windows(pid, func, param);
}

struct _modinfo {
   address addr;
   char*   full_path;   // point to a char buffer
   int     buflen;      // size of the buffer
   address base_addr;
};

static int _locate_module_by_addr(int pid, char * mod_fname, address base_addr,
                                  unsigned size, void * param) {
   struct _modinfo *pmod = (struct _modinfo *)param;
   if (!pmod) return -1;

   if (base_addr     <= pmod->addr &&
       base_addr+size > pmod->addr) {
     // if a buffer is provided, copy path name to the buffer
     if (pmod->full_path) {
       jio_snprintf(pmod->full_path, pmod->buflen, "%s", mod_fname);
     }
     pmod->base_addr = base_addr;
     return 1;
   }
   return 0;
}

bool os::dll_address_to_library_name(address addr, char* buf,
                                     int buflen, int* offset) {
// NOTE: the reason we don't use SymGetModuleInfo() is it doesn't always
//       return the full path to the DLL file, sometimes it returns path
//       to the corresponding PDB file (debug info); sometimes it only
//       returns partial path, which makes life painful.

   struct _modinfo mi;
   mi.addr      = addr;
   mi.full_path = buf;
   mi.buflen    = buflen;
   int pid = os::current_process_id();
   if (enumerate_modules(pid, _locate_module_by_addr, (void *)&mi)) {
      // buf already contains path name
      if (offset) *offset = addr - mi.base_addr;
      return true;
   } else {
      if (buf) buf[0] = '\0';
      if (offset) *offset = -1;
      return false;
   }
}

bool os::dll_address_to_function_name(address addr, char *buf,
                                      int buflen, int *offset) {
  // Unimplemented on Windows - in order to use SymGetSymFromAddr(),
  // we need to initialize imagehlp/dbghelp, then load symbol table
  // for every module. That's too much work to do after a fatal error.
  // For an example on how to implement this function, see 1.4.2.
  if (offset)  *offset  = -1;
  if (buf) buf[0] = '\0';
  return false;
}

void* os::dll_lookup(void* handle, const char* name) {
  return GetProcAddress((HMODULE)handle, name);
}

// save the start and end address of jvm.dll into param[0] and param[1]
static int _locate_jvm_dll(int pid, char* mod_fname, address base_addr,
                    unsigned size, void * param) {
   if (!param) return -1;

   if (base_addr     <= (address)_locate_jvm_dll &&
       base_addr+size > (address)_locate_jvm_dll) {
         ((address*)param)[0] = base_addr;
         ((address*)param)[1] = base_addr + size;
         return 1;
   }
   return 0;
}

address vm_lib_location[2];    // start and end address of jvm.dll

// check if addr is inside jvm.dll
bool os::address_is_in_vm(address addr) {
  if (!vm_lib_location[0] || !vm_lib_location[1]) {
    int pid = os::current_process_id();
    if (!enumerate_modules(pid, _locate_jvm_dll, (void *)vm_lib_location)) {
      assert(false, "Can't find jvm module.");
      return false;
    }
  }

  return (vm_lib_location[0] <= addr) && (addr < vm_lib_location[1]);
}

// print module info; param is outputStream*
static int _print_module(int pid, char* fname, address base,
                         unsigned size, void* param) {
   if (!param) return -1;

   outputStream* st = (outputStream*)param;

   address end_addr = base + size;
   st->print(PTR_FORMAT " - " PTR_FORMAT " \t%s\n", base, end_addr, fname);
   return 0;
}

// Loads .dll/.so and
// in case of error it checks if .dll/.so was built for the
// same architecture as Hotspot is running on
void * os::dll_load(const char *name, char *ebuf, int ebuflen)
{
  void * result = LoadLibrary(name);
  if (result != NULL)
  {
    return result;
  }

  long errcode = GetLastError();
  if (errcode == ERROR_MOD_NOT_FOUND) {
    strncpy(ebuf, "Can't find dependent libraries", ebuflen-1);
    ebuf[ebuflen-1]='\0';
    return NULL;
  }

  // Parsing dll below
  // If we can read dll-info and find that dll was built
  // for an architecture other than Hotspot is running in
  // - then print to buffer "DLL was built for a different architecture"
  // else call getLastErrorString to obtain system error message

  // Read system error message into ebuf
  // It may or may not be overwritten below (in the for loop and just above)
  getLastErrorString(ebuf, (size_t) ebuflen);
  ebuf[ebuflen-1]='\0';
  int file_descriptor=::open(name, O_RDONLY | O_BINARY, 0);
  if (file_descriptor<0)
  {
    return NULL;
  }

  uint32_t signature_offset;
  uint16_t lib_arch=0;
  bool failed_to_get_lib_arch=
  (
    //Go to position 3c in the dll
    (os::seek_to_file_offset(file_descriptor,IMAGE_FILE_PTR_TO_SIGNATURE)<0)
    ||
    // Read loacation of signature
    (sizeof(signature_offset)!=
      (os::read(file_descriptor, (void*)&signature_offset,sizeof(signature_offset))))
    ||
    //Go to COFF File Header in dll
    //that is located after"signature" (4 bytes long)
    (os::seek_to_file_offset(file_descriptor,
      signature_offset+IMAGE_FILE_SIGNATURE_LENGTH)<0)
    ||
    //Read field that contains code of architecture
    // that dll was build for
    (sizeof(lib_arch)!=
      (os::read(file_descriptor, (void*)&lib_arch,sizeof(lib_arch))))
  );

  ::close(file_descriptor);
  if (failed_to_get_lib_arch)
  {
    // file i/o error - report getLastErrorString(...) msg
    return NULL;
  }

  typedef struct
  {
    uint16_t arch_code;
    char* arch_name;
  } arch_t;

  static const arch_t arch_array[]={
    {IMAGE_FILE_MACHINE_I386,      (char*)"IA 32"},
    {IMAGE_FILE_MACHINE_AMD64,     (char*)"AMD 64"},
    {IMAGE_FILE_MACHINE_IA64,      (char*)"IA 64"}
  };
  #if   (defined _M_IA64)
    static const uint16_t running_arch=IMAGE_FILE_MACHINE_IA64;
  #elif (defined _M_AMD64)
    static const uint16_t running_arch=IMAGE_FILE_MACHINE_AMD64;
  #elif (defined _M_IX86)
    static const uint16_t running_arch=IMAGE_FILE_MACHINE_I386;
  #else
    #error Method os::dll_load requires that one of following \
           is defined :_M_IA64,_M_AMD64 or _M_IX86
  #endif


  // Obtain a string for printf operation
  // lib_arch_str shall contain string what platform this .dll was built for
  // running_arch_str shall string contain what platform Hotspot was built for
  char *running_arch_str=NULL,*lib_arch_str=NULL;
  for (unsigned int i=0;i<ARRAY_SIZE(arch_array);i++)
  {
    if (lib_arch==arch_array[i].arch_code)
      lib_arch_str=arch_array[i].arch_name;
    if (running_arch==arch_array[i].arch_code)
      running_arch_str=arch_array[i].arch_name;
  }

  assert(running_arch_str,
    "Didn't find runing architecture code in arch_array");

  // If the architure is right
  // but some other error took place - report getLastErrorString(...) msg
  if (lib_arch == running_arch)
  {
    return NULL;
  }

  if (lib_arch_str!=NULL)
  {
    ::_snprintf(ebuf, ebuflen-1,
      "Can't load %s-bit .dll on a %s-bit platform",
      lib_arch_str,running_arch_str);
  }
  else
  {
    // don't know what architecture this dll was build for
    ::_snprintf(ebuf, ebuflen-1,
      "Can't load this .dll (machine code=0x%x) on a %s-bit platform",
      lib_arch,running_arch_str);
  }

  return NULL;
}


void os::print_dll_info(outputStream *st) {
   int pid = os::current_process_id();
   st->print_cr("Dynamic libraries:");
   enumerate_modules(pid, _print_module, (void *)st);
}

// function pointer to Windows API "GetNativeSystemInfo".
typedef void (WINAPI *GetNativeSystemInfo_func_type)(LPSYSTEM_INFO);
static GetNativeSystemInfo_func_type _GetNativeSystemInfo;

void os::print_os_info(outputStream* st) {
  st->print("OS:");

  OSVERSIONINFOEX osvi;
  ZeroMemory(&osvi, sizeof(OSVERSIONINFOEX));
  osvi.dwOSVersionInfoSize = sizeof(OSVERSIONINFOEX);

  if (!GetVersionEx((OSVERSIONINFO *)&osvi)) {
    st->print_cr("N/A");
    return;
  }

  int os_vers = osvi.dwMajorVersion * 1000 + osvi.dwMinorVersion;
  if (osvi.dwPlatformId == VER_PLATFORM_WIN32_NT) {
    switch (os_vers) {
    case 3051: st->print(" Windows NT 3.51"); break;
    case 4000: st->print(" Windows NT 4.0"); break;
    case 5000: st->print(" Windows 2000"); break;
    case 5001: st->print(" Windows XP"); break;
    case 5002:
    case 6000: {
      // Retrieve SYSTEM_INFO from GetNativeSystemInfo call so that we could
      // find out whether we are running on 64 bit processor or not.
      SYSTEM_INFO si;
      ZeroMemory(&si, sizeof(SYSTEM_INFO));
      // Check to see if _GetNativeSystemInfo has been initialized.
      if (_GetNativeSystemInfo == NULL) {
        HMODULE hKernel32 = GetModuleHandle(TEXT("kernel32.dll"));
        _GetNativeSystemInfo =
            CAST_TO_FN_PTR(GetNativeSystemInfo_func_type,
                           GetProcAddress(hKernel32,
                                          "GetNativeSystemInfo"));
        if (_GetNativeSystemInfo == NULL)
          GetSystemInfo(&si);
      } else {
        _GetNativeSystemInfo(&si);
      }
      if (os_vers == 5002) {
        if (osvi.wProductType == VER_NT_WORKSTATION &&
            si.wProcessorArchitecture == PROCESSOR_ARCHITECTURE_AMD64)
          st->print(" Windows XP x64 Edition");
        else
            st->print(" Windows Server 2003 family");
      } else { // os_vers == 6000
        if (osvi.wProductType == VER_NT_WORKSTATION)
            st->print(" Windows Vista");
        else
            st->print(" Windows Server 2008");
        if (si.wProcessorArchitecture == PROCESSOR_ARCHITECTURE_AMD64)
            st->print(" , 64 bit");
      }
      break;
    }
    default: // future windows, print out its major and minor versions
      st->print(" Windows NT %d.%d", osvi.dwMajorVersion, osvi.dwMinorVersion);
    }
  } else {
    switch (os_vers) {
    case 4000: st->print(" Windows 95"); break;
    case 4010: st->print(" Windows 98"); break;
    case 4090: st->print(" Windows Me"); break;
    default: // future windows, print out its major and minor versions
      st->print(" Windows %d.%d", osvi.dwMajorVersion, osvi.dwMinorVersion);
    }
  }
  st->print(" Build %d", osvi.dwBuildNumber);
  st->print(" %s", osvi.szCSDVersion);           // service pack
  st->cr();
}

void os::print_memory_info(outputStream* st) {
  st->print("Memory:");
  st->print(" %dk page", os::vm_page_size()>>10);

  // FIXME: GlobalMemoryStatus() may return incorrect value if total memory
  // is larger than 4GB
  MEMORYSTATUS ms;
  GlobalMemoryStatus(&ms);

  st->print(", physical %uk", os::physical_memory() >> 10);
  st->print("(%uk free)", os::available_memory() >> 10);

  st->print(", swap %uk", ms.dwTotalPageFile >> 10);
  st->print("(%uk free)", ms.dwAvailPageFile >> 10);
  st->cr();
}

void os::print_siginfo(outputStream *st, void *siginfo) {
  EXCEPTION_RECORD* er = (EXCEPTION_RECORD*)siginfo;
  st->print("siginfo:");
  st->print(" ExceptionCode=0x%x", er->ExceptionCode);

  if (er->ExceptionCode == EXCEPTION_ACCESS_VIOLATION &&
      er->NumberParameters >= 2) {
      switch (er->ExceptionInformation[0]) {
      case 0: st->print(", reading address"); break;
      case 1: st->print(", writing address"); break;
      default: st->print(", ExceptionInformation=" INTPTR_FORMAT,
                            er->ExceptionInformation[0]);
      }
      st->print(" " INTPTR_FORMAT, er->ExceptionInformation[1]);
  } else if (er->ExceptionCode == EXCEPTION_IN_PAGE_ERROR &&
             er->NumberParameters >= 2 && UseSharedSpaces) {
    FileMapInfo* mapinfo = FileMapInfo::current_info();
    if (mapinfo->is_in_shared_space((void*)er->ExceptionInformation[1])) {
      st->print("\n\nError accessing class data sharing archive."       \
                " Mapped file inaccessible during execution, "          \
                " possible disk/network problem.");
    }
  } else {
    int num = er->NumberParameters;
    if (num > 0) {
      st->print(", ExceptionInformation=");
      for (int i = 0; i < num; i++) {
        st->print(INTPTR_FORMAT " ", er->ExceptionInformation[i]);
      }
    }
  }
  st->cr();
}

void os::print_signal_handlers(outputStream* st, char* buf, size_t buflen) {
  // do nothing
}

static char saved_jvm_path[MAX_PATH] = {0};

// Find the full path to the current module, jvm.dll or jvm_g.dll
void os::jvm_path(char *buf, jint buflen) {
  // Error checking.
  if (buflen < MAX_PATH) {
    assert(false, "must use a large-enough buffer");
    buf[0] = '\0';
    return;
  }
  // Lazy resolve the path to current module.
  if (saved_jvm_path[0] != 0) {
    strcpy(buf, saved_jvm_path);
    return;
  }

  GetModuleFileName(vm_lib_handle, buf, buflen);
  strcpy(saved_jvm_path, buf);
}


void os::print_jni_name_prefix_on(outputStream* st, int args_size) {
#ifndef _WIN64
  st->print("_");
#endif
}


void os::print_jni_name_suffix_on(outputStream* st, int args_size) {
#ifndef _WIN64
  st->print("@%d", args_size  * sizeof(int));
#endif
}

// sun.misc.Signal
// NOTE that this is a workaround for an apparent kernel bug where if
// a signal handler for SIGBREAK is installed then that signal handler
// takes priority over the console control handler for CTRL_CLOSE_EVENT.
// See bug 4416763.
static void (*sigbreakHandler)(int) = NULL;

static void UserHandler(int sig, void *siginfo, void *context) {
  os::signal_notify(sig);
  // We need to reinstate the signal handler each time...
  os::signal(sig, (void*)UserHandler);
}

void* os::user_handler() {
  return (void*) UserHandler;
}

void* os::signal(int signal_number, void* handler) {
  if ((signal_number == SIGBREAK) && (!ReduceSignalUsage)) {
    void (*oldHandler)(int) = sigbreakHandler;
    sigbreakHandler = (void (*)(int)) handler;
    return (void*) oldHandler;
  } else {
    return (void*)::signal(signal_number, (void (*)(int))handler);
  }
}

void os::signal_raise(int signal_number) {
  raise(signal_number);
}

// The Win32 C runtime library maps all console control events other than ^C
// into SIGBREAK, which makes it impossible to distinguish ^BREAK from close,
// logoff, and shutdown events.  We therefore install our own console handler
// that raises SIGTERM for the latter cases.
//
static BOOL WINAPI consoleHandler(DWORD event) {
  switch(event) {
    case CTRL_C_EVENT:
      if (is_error_reported()) {
        // Ctrl-C is pressed during error reporting, likely because the error
        // handler fails to abort. Let VM die immediately.
        os::die();
      }

      os::signal_raise(SIGINT);
      return TRUE;
      break;
    case CTRL_BREAK_EVENT:
      if (sigbreakHandler != NULL) {
        (*sigbreakHandler)(SIGBREAK);
      }
      return TRUE;
      break;
    case CTRL_CLOSE_EVENT:
    case CTRL_LOGOFF_EVENT:
    case CTRL_SHUTDOWN_EVENT:
      os::signal_raise(SIGTERM);
      return TRUE;
      break;
    default:
      break;
  }
  return FALSE;
}

/*
 * The following code is moved from os.cpp for making this
 * code platform specific, which it is by its very nature.
 */

// Return maximum OS signal used + 1 for internal use only
// Used as exit signal for signal_thread
int os::sigexitnum_pd(){
  return NSIG;
}

// a counter for each possible signal value, including signal_thread exit signal
static volatile jint pending_signals[NSIG+1] = { 0 };
static HANDLE sig_sem;

void os::signal_init_pd() {
  // Initialize signal structures
  memset((void*)pending_signals, 0, sizeof(pending_signals));

  sig_sem = ::CreateSemaphore(NULL, 0, NSIG+1, NULL);

  // Programs embedding the VM do not want it to attempt to receive
  // events like CTRL_LOGOFF_EVENT, which are used to implement the
  // shutdown hooks mechanism introduced in 1.3.  For example, when
  // the VM is run as part of a Windows NT service (i.e., a servlet
  // engine in a web server), the correct behavior is for any console
  // control handler to return FALSE, not TRUE, because the OS's
  // "final" handler for such events allows the process to continue if
  // it is a service (while terminating it if it is not a service).
  // To make this behavior uniform and the mechanism simpler, we
  // completely disable the VM's usage of these console events if -Xrs
  // (=ReduceSignalUsage) is specified.  This means, for example, that
  // the CTRL-BREAK thread dump mechanism is also disabled in this
  // case.  See bugs 4323062, 4345157, and related bugs.

  if (!ReduceSignalUsage) {
    // Add a CTRL-C handler
    SetConsoleCtrlHandler(consoleHandler, TRUE);
  }
}

void os::signal_notify(int signal_number) {
  BOOL ret;

  Atomic::inc(&pending_signals[signal_number]);
  ret = ::ReleaseSemaphore(sig_sem, 1, NULL);
  assert(ret != 0, "ReleaseSemaphore() failed");
}

static int check_pending_signals(bool wait_for_signal) {
  DWORD ret;
  while (true) {
    for (int i = 0; i < NSIG + 1; i++) {
      jint n = pending_signals[i];
      if (n > 0 && n == Atomic::cmpxchg(n - 1, &pending_signals[i], n)) {
        return i;
      }
    }
    if (!wait_for_signal) {
      return -1;
    }

    JavaThread *thread = JavaThread::current();

    ThreadBlockInVM tbivm(thread);

    bool threadIsSuspended;
    do {
      thread->set_suspend_equivalent();
      // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self()
      ret = ::WaitForSingleObject(sig_sem, INFINITE);
      assert(ret == WAIT_OBJECT_0, "WaitForSingleObject() failed");

      // were we externally suspended while we were waiting?
      threadIsSuspended = thread->handle_special_suspend_equivalent_condition();
      if (threadIsSuspended) {
        //
        // The semaphore has been incremented, but while we were waiting
        // another thread suspended us. We don't want to continue running
        // while suspended because that would surprise the thread that
        // suspended us.
        //
        ret = ::ReleaseSemaphore(sig_sem, 1, NULL);
        assert(ret != 0, "ReleaseSemaphore() failed");

        thread->java_suspend_self();
      }
    } while (threadIsSuspended);
  }
}

int os::signal_lookup() {
  return check_pending_signals(false);
}

int os::signal_wait() {
  return check_pending_signals(true);
}

// Implicit OS exception handling

LONG Handle_Exception(struct _EXCEPTION_POINTERS* exceptionInfo, address handler) {
  JavaThread* thread = JavaThread::current();
  // Save pc in thread
#ifdef _M_IA64
  thread->set_saved_exception_pc((address)exceptionInfo->ContextRecord->StIIP);
  // Set pc to handler
  exceptionInfo->ContextRecord->StIIP = (DWORD64)handler;
#elif _M_AMD64
  thread->set_saved_exception_pc((address)exceptionInfo->ContextRecord->Rip);
  // Set pc to handler
  exceptionInfo->ContextRecord->Rip = (DWORD64)handler;
#else
  thread->set_saved_exception_pc((address)exceptionInfo->ContextRecord->Eip);
  // Set pc to handler
  exceptionInfo->ContextRecord->Eip = (LONG)handler;
#endif

  // Continue the execution
  return EXCEPTION_CONTINUE_EXECUTION;
}


// Used for PostMortemDump
extern "C" void safepoints();
extern "C" void find(int x);
extern "C" void events();

// According to Windows API documentation, an illegal instruction sequence should generate
// the 0xC000001C exception code. However, real world experience shows that occasionnaly
// the execution of an illegal instruction can generate the exception code 0xC000001E. This
// seems to be an undocumented feature of Win NT 4.0 (and probably other Windows systems).

#define EXCEPTION_ILLEGAL_INSTRUCTION_2 0xC000001E

// From "Execution Protection in the Windows Operating System" draft 0.35
// Once a system header becomes available, the "real" define should be
// included or copied here.
#define EXCEPTION_INFO_EXEC_VIOLATION 0x08

#define def_excpt(val) #val, val

struct siglabel {
  char *name;
  int   number;
};

struct siglabel exceptlabels[] = {
    def_excpt(EXCEPTION_ACCESS_VIOLATION),
    def_excpt(EXCEPTION_DATATYPE_MISALIGNMENT),
    def_excpt(EXCEPTION_BREAKPOINT),
    def_excpt(EXCEPTION_SINGLE_STEP),
    def_excpt(EXCEPTION_ARRAY_BOUNDS_EXCEEDED),
    def_excpt(EXCEPTION_FLT_DENORMAL_OPERAND),
    def_excpt(EXCEPTION_FLT_DIVIDE_BY_ZERO),
    def_excpt(EXCEPTION_FLT_INEXACT_RESULT),
    def_excpt(EXCEPTION_FLT_INVALID_OPERATION),
    def_excpt(EXCEPTION_FLT_OVERFLOW),
    def_excpt(EXCEPTION_FLT_STACK_CHECK),
    def_excpt(EXCEPTION_FLT_UNDERFLOW),
    def_excpt(EXCEPTION_INT_DIVIDE_BY_ZERO),
    def_excpt(EXCEPTION_INT_OVERFLOW),
    def_excpt(EXCEPTION_PRIV_INSTRUCTION),
    def_excpt(EXCEPTION_IN_PAGE_ERROR),
    def_excpt(EXCEPTION_ILLEGAL_INSTRUCTION),
    def_excpt(EXCEPTION_ILLEGAL_INSTRUCTION_2),
    def_excpt(EXCEPTION_NONCONTINUABLE_EXCEPTION),
    def_excpt(EXCEPTION_STACK_OVERFLOW),
    def_excpt(EXCEPTION_INVALID_DISPOSITION),
    def_excpt(EXCEPTION_GUARD_PAGE),
    def_excpt(EXCEPTION_INVALID_HANDLE),
    NULL, 0
};

const char* os::exception_name(int exception_code, char *buf, size_t size) {
  for (int i = 0; exceptlabels[i].name != NULL; i++) {
    if (exceptlabels[i].number == exception_code) {
       jio_snprintf(buf, size, "%s", exceptlabels[i].name);
       return buf;
    }
  }

  return NULL;
}

//-----------------------------------------------------------------------------
LONG Handle_IDiv_Exception(struct _EXCEPTION_POINTERS* exceptionInfo) {
  // handle exception caused by idiv; should only happen for -MinInt/-1
  // (division by zero is handled explicitly)
#ifdef _M_IA64
  assert(0, "Fix Handle_IDiv_Exception");
#elif _M_AMD64
  PCONTEXT ctx = exceptionInfo->ContextRecord;
  address pc = (address)ctx->Rip;
  NOT_PRODUCT(Events::log("idiv overflow exception at " INTPTR_FORMAT , pc));
  assert(pc[0] == 0xF7, "not an idiv opcode");
  assert((pc[1] & ~0x7) == 0xF8, "cannot handle non-register operands");
  assert(ctx->Rax == min_jint, "unexpected idiv exception");
  // set correct result values and continue after idiv instruction
  ctx->Rip = (DWORD)pc + 2;        // idiv reg, reg  is 2 bytes
  ctx->Rax = (DWORD)min_jint;      // result
  ctx->Rdx = (DWORD)0;             // remainder
  // Continue the execution
#else
  PCONTEXT ctx = exceptionInfo->ContextRecord;
  address pc = (address)ctx->Eip;
  NOT_PRODUCT(Events::log("idiv overflow exception at " INTPTR_FORMAT , pc));
  assert(pc[0] == 0xF7, "not an idiv opcode");
  assert((pc[1] & ~0x7) == 0xF8, "cannot handle non-register operands");
  assert(ctx->Eax == min_jint, "unexpected idiv exception");
  // set correct result values and continue after idiv instruction
  ctx->Eip = (DWORD)pc + 2;        // idiv reg, reg  is 2 bytes
  ctx->Eax = (DWORD)min_jint;      // result
  ctx->Edx = (DWORD)0;             // remainder
  // Continue the execution
#endif
  return EXCEPTION_CONTINUE_EXECUTION;
}

#ifndef  _WIN64
//-----------------------------------------------------------------------------
LONG WINAPI Handle_FLT_Exception(struct _EXCEPTION_POINTERS* exceptionInfo) {
  // handle exception caused by native method modifying control word
  PCONTEXT ctx = exceptionInfo->ContextRecord;
  DWORD exception_code = exceptionInfo->ExceptionRecord->ExceptionCode;

  switch (exception_code) {
    case EXCEPTION_FLT_DENORMAL_OPERAND:
    case EXCEPTION_FLT_DIVIDE_BY_ZERO:
    case EXCEPTION_FLT_INEXACT_RESULT:
    case EXCEPTION_FLT_INVALID_OPERATION:
    case EXCEPTION_FLT_OVERFLOW:
    case EXCEPTION_FLT_STACK_CHECK:
    case EXCEPTION_FLT_UNDERFLOW:
      jint fp_control_word = (* (jint*) StubRoutines::addr_fpu_cntrl_wrd_std());
      if (fp_control_word != ctx->FloatSave.ControlWord) {
        // Restore FPCW and mask out FLT exceptions
        ctx->FloatSave.ControlWord = fp_control_word | 0xffffffc0;
        // Mask out pending FLT exceptions
        ctx->FloatSave.StatusWord &=  0xffffff00;
        return EXCEPTION_CONTINUE_EXECUTION;
      }
  }

  if (prev_uef_handler != NULL) {
    // We didn't handle this exception so pass it to the previous
    // UnhandledExceptionFilter.
    return (prev_uef_handler)(exceptionInfo);
  }

  return EXCEPTION_CONTINUE_SEARCH;
}
#else //_WIN64
/*
  On Windows, the mxcsr control bits are non-volatile across calls
  See also CR 6192333
  If EXCEPTION_FLT_* happened after some native method modified
  mxcsr - it is not a jvm fault.
  However should we decide to restore of mxcsr after a faulty
  native method we can uncomment following code
      jint MxCsr = INITIAL_MXCSR;
        // we can't use StubRoutines::addr_mxcsr_std()
        // because in Win64 mxcsr is not saved there
      if (MxCsr != ctx->MxCsr) {
        ctx->MxCsr = MxCsr;
        return EXCEPTION_CONTINUE_EXECUTION;
      }

*/
#endif //_WIN64


// Fatal error reporting is single threaded so we can make this a
// static and preallocated.  If it's more than MAX_PATH silently ignore
// it.
static char saved_error_file[MAX_PATH] = {0};

void os::set_error_file(const char *logfile) {
  if (strlen(logfile) <= MAX_PATH) {
    strncpy(saved_error_file, logfile, MAX_PATH);
  }
}

static inline void report_error(Thread* t, DWORD exception_code,
                                address addr, void* siginfo, void* context) {
  VMError err(t, exception_code, addr, siginfo, context);
  err.report_and_die();

  // If UseOsErrorReporting, this will return here and save the error file
  // somewhere where we can find it in the minidump.
}

//-----------------------------------------------------------------------------
LONG WINAPI topLevelExceptionFilter(struct _EXCEPTION_POINTERS* exceptionInfo) {
  if (InterceptOSException) return EXCEPTION_CONTINUE_SEARCH;
  DWORD exception_code = exceptionInfo->ExceptionRecord->ExceptionCode;
#ifdef _M_IA64
  address pc = (address) exceptionInfo->ContextRecord->StIIP;
#elif _M_AMD64
  address pc = (address) exceptionInfo->ContextRecord->Rip;
#else
  address pc = (address) exceptionInfo->ContextRecord->Eip;
#endif
  Thread* t = ThreadLocalStorage::get_thread_slow();          // slow & steady

#ifndef _WIN64
  // Execution protection violation - win32 running on AMD64 only
  // Handled first to avoid misdiagnosis as a "normal" access violation;
  // This is safe to do because we have a new/unique ExceptionInformation
  // code for this condition.
  if (exception_code == EXCEPTION_ACCESS_VIOLATION) {
    PEXCEPTION_RECORD exceptionRecord = exceptionInfo->ExceptionRecord;
    int exception_subcode = (int) exceptionRecord->ExceptionInformation[0];
    address addr = (address) exceptionRecord->ExceptionInformation[1];

    if (exception_subcode == EXCEPTION_INFO_EXEC_VIOLATION) {
      int page_size = os::vm_page_size();

      // Make sure the pc and the faulting address are sane.
      //
      // If an instruction spans a page boundary, and the page containing
      // the beginning of the instruction is executable but the following
      // page is not, the pc and the faulting address might be slightly
      // different - we still want to unguard the 2nd page in this case.
      //
      // 15 bytes seems to be a (very) safe value for max instruction size.
      bool pc_is_near_addr =
        (pointer_delta((void*) addr, (void*) pc, sizeof(char)) < 15);
      bool instr_spans_page_boundary =
        (align_size_down((intptr_t) pc ^ (intptr_t) addr,
                         (intptr_t) page_size) > 0);

      if (pc == addr || (pc_is_near_addr && instr_spans_page_boundary)) {
        static volatile address last_addr =
          (address) os::non_memory_address_word();

        // In conservative mode, don't unguard unless the address is in the VM
        if (UnguardOnExecutionViolation > 0 && addr != last_addr &&
            (UnguardOnExecutionViolation > 1 || os::address_is_in_vm(addr))) {

          // Set memory to RWX and retry
          address page_start =
            (address) align_size_down((intptr_t) addr, (intptr_t) page_size);
          bool res = os::protect_memory((char*) page_start, page_size,
                                        os::MEM_PROT_RWX);

          if (PrintMiscellaneous && Verbose) {
            char buf[256];
            jio_snprintf(buf, sizeof(buf), "Execution protection violation "
                         "at " INTPTR_FORMAT
                         ", unguarding " INTPTR_FORMAT ": %s", addr,
                         page_start, (res ? "success" : strerror(errno)));
            tty->print_raw_cr(buf);
          }

          // Set last_addr so if we fault again at the same address, we don't
          // end up in an endless loop.
          //
          // There are two potential complications here.  Two threads trapping
          // at the same address at the same time could cause one of the
          // threads to think it already unguarded, and abort the VM.  Likely
          // very rare.
          //
          // The other race involves two threads alternately trapping at
          // different addresses and failing to unguard the page, resulting in
          // an endless loop.  This condition is probably even more unlikely
          // than the first.
          //
          // Although both cases could be avoided by using locks or thread
          // local last_addr, these solutions are unnecessary complication:
          // this handler is a best-effort safety net, not a complete solution.
          // It is disabled by default and should only be used as a workaround
          // in case we missed any no-execute-unsafe VM code.

          last_addr = addr;

          return EXCEPTION_CONTINUE_EXECUTION;
        }
      }

      // Last unguard failed or not unguarding
      tty->print_raw_cr("Execution protection violation");
      report_error(t, exception_code, addr, exceptionInfo->ExceptionRecord,
                   exceptionInfo->ContextRecord);
      return EXCEPTION_CONTINUE_SEARCH;
    }
  }
#endif // _WIN64

  // Check to see if we caught the safepoint code in the
  // process of write protecting the memory serialization page.
  // It write enables the page immediately after protecting it
  // so just return.
  if ( exception_code == EXCEPTION_ACCESS_VIOLATION ) {
    JavaThread* thread = (JavaThread*) t;
    PEXCEPTION_RECORD exceptionRecord = exceptionInfo->ExceptionRecord;
    address addr = (address) exceptionRecord->ExceptionInformation[1];
    if ( os::is_memory_serialize_page(thread, addr) ) {
      // Block current thread until the memory serialize page permission restored.
      os::block_on_serialize_page_trap();
      return EXCEPTION_CONTINUE_EXECUTION;
    }
  }


  if (t != NULL && t->is_Java_thread()) {
    JavaThread* thread = (JavaThread*) t;
    bool in_java = thread->thread_state() == _thread_in_Java;

    // Handle potential stack overflows up front.
    if (exception_code == EXCEPTION_STACK_OVERFLOW) {
      if (os::uses_stack_guard_pages()) {
#ifdef _M_IA64
        //
        // If it's a legal stack address continue, Windows will map it in.
        //
        PEXCEPTION_RECORD exceptionRecord = exceptionInfo->ExceptionRecord;
        address addr = (address) exceptionRecord->ExceptionInformation[1];
        if (addr > thread->stack_yellow_zone_base() && addr < thread->stack_base() )
          return EXCEPTION_CONTINUE_EXECUTION;

        // The register save area is the same size as the memory stack
        // and starts at the page just above the start of the memory stack.
        // If we get a fault in this area, we've run out of register
        // stack.  If we are in java, try throwing a stack overflow exception.
        if (addr > thread->stack_base() &&
                      addr <= (thread->stack_base()+thread->stack_size()) ) {
          char buf[256];
          jio_snprintf(buf, sizeof(buf),
                       "Register stack overflow, addr:%p, stack_base:%p\n",
                       addr, thread->stack_base() );
          tty->print_raw_cr(buf);
          // If not in java code, return and hope for the best.
          return in_java ? Handle_Exception(exceptionInfo,
            SharedRuntime::continuation_for_implicit_exception(thread, pc, SharedRuntime::STACK_OVERFLOW))
            :  EXCEPTION_CONTINUE_EXECUTION;
        }
#endif
        if (thread->stack_yellow_zone_enabled()) {
          // Yellow zone violation.  The o/s has unprotected the first yellow
          // zone page for us.  Note:  must call disable_stack_yellow_zone to
          // update the enabled status, even if the zone contains only one page.
          thread->disable_stack_yellow_zone();
          // If not in java code, return and hope for the best.
          return in_java ? Handle_Exception(exceptionInfo,
            SharedRuntime::continuation_for_implicit_exception(thread, pc, SharedRuntime::STACK_OVERFLOW))
            :  EXCEPTION_CONTINUE_EXECUTION;
        } else {
          // Fatal red zone violation.
          thread->disable_stack_red_zone();
          tty->print_raw_cr("An unrecoverable stack overflow has occurred.");
          report_error(t, exception_code, pc, exceptionInfo->ExceptionRecord,
                       exceptionInfo->ContextRecord);
          return EXCEPTION_CONTINUE_SEARCH;
        }
      } else if (in_java) {
        // JVM-managed guard pages cannot be used on win95/98.  The o/s provides
        // a one-time-only guard page, which it has released to us.  The next
        // stack overflow on this thread will result in an ACCESS_VIOLATION.
        return Handle_Exception(exceptionInfo,
          SharedRuntime::continuation_for_implicit_exception(thread, pc, SharedRuntime::STACK_OVERFLOW));
      } else {
        // Can only return and hope for the best.  Further stack growth will
        // result in an ACCESS_VIOLATION.
        return EXCEPTION_CONTINUE_EXECUTION;
      }
    } else if (exception_code == EXCEPTION_ACCESS_VIOLATION) {
      // Either stack overflow or null pointer exception.
      if (in_java) {
        PEXCEPTION_RECORD exceptionRecord = exceptionInfo->ExceptionRecord;
        address addr = (address) exceptionRecord->ExceptionInformation[1];
        address stack_end = thread->stack_base() - thread->stack_size();
        if (addr < stack_end && addr >= stack_end - os::vm_page_size()) {
          // Stack overflow.
          assert(!os::uses_stack_guard_pages(),
            "should be caught by red zone code above.");
          return Handle_Exception(exceptionInfo,
            SharedRuntime::continuation_for_implicit_exception(thread, pc, SharedRuntime::STACK_OVERFLOW));
        }
        //
        // Check for safepoint polling and implicit null
        // We only expect null pointers in the stubs (vtable)
        // the rest are checked explicitly now.
        //
        CodeBlob* cb = CodeCache::find_blob(pc);
        if (cb != NULL) {
          if (os::is_poll_address(addr)) {
            address stub = SharedRuntime::get_poll_stub(pc);
            return Handle_Exception(exceptionInfo, stub);
          }
        }
        {
#ifdef _WIN64
          //
          // If it's a legal stack address map the entire region in
          //
          PEXCEPTION_RECORD exceptionRecord = exceptionInfo->ExceptionRecord;
          address addr = (address) exceptionRecord->ExceptionInformation[1];
          if (addr > thread->stack_yellow_zone_base() && addr < thread->stack_base() ) {
                  addr = (address)((uintptr_t)addr &
                         (~((uintptr_t)os::vm_page_size() - (uintptr_t)1)));
                  os::commit_memory( (char *)addr, thread->stack_base() - addr );
                  return EXCEPTION_CONTINUE_EXECUTION;
          }
          else
#endif
          {
            // Null pointer exception.
#ifdef _M_IA64
            // We catch register stack overflows in compiled code by doing
            // an explicit compare and executing a st8(G0, G0) if the
            // BSP enters into our guard area.  We test for the overflow
            // condition and fall into the normal null pointer exception
            // code if BSP hasn't overflowed.
            if ( in_java ) {
              if(thread->register_stack_overflow()) {
                assert((address)exceptionInfo->ContextRecord->IntS3 ==
                                thread->register_stack_limit(),
                               "GR7 doesn't contain register_stack_limit");
                // Disable the yellow zone which sets the state that
                // we've got a stack overflow problem.
                if (thread->stack_yellow_zone_enabled()) {
                  thread->disable_stack_yellow_zone();
                }
                // Give us some room to process the exception
                thread->disable_register_stack_guard();
                // Update GR7 with the new limit so we can continue running
                // compiled code.
                exceptionInfo->ContextRecord->IntS3 =
                               (ULONGLONG)thread->register_stack_limit();
                return Handle_Exception(exceptionInfo,
                       SharedRuntime::continuation_for_implicit_exception(thread, pc, SharedRuntime::STACK_OVERFLOW));
              } else {
                //
                // Check for implicit null
                // We only expect null pointers in the stubs (vtable)
                // the rest are checked explicitly now.
                //
                if (((uintptr_t)addr) < os::vm_page_size() ) {
                  // an access to the first page of VM--assume it is a null pointer
                  address stub = SharedRuntime::continuation_for_implicit_exception(thread, pc, SharedRuntime::IMPLICIT_NULL);
                  if (stub != NULL) return Handle_Exception(exceptionInfo, stub);
                }
              }
            } // in_java

            // IA64 doesn't use implicit null checking yet. So we shouldn't
            // get here.
            tty->print_raw_cr("Access violation, possible null pointer exception");
            report_error(t, exception_code, pc, exceptionInfo->ExceptionRecord,
                         exceptionInfo->ContextRecord);
            return EXCEPTION_CONTINUE_SEARCH;
#else /* !IA64 */

            // Windows 98 reports faulting addresses incorrectly
            if (!MacroAssembler::needs_explicit_null_check((intptr_t)addr) ||
                !os::win32::is_nt()) {
              address stub = SharedRuntime::continuation_for_implicit_exception(thread, pc, SharedRuntime::IMPLICIT_NULL);
              if (stub != NULL) return Handle_Exception(exceptionInfo, stub);
            }
            report_error(t, exception_code, pc, exceptionInfo->ExceptionRecord,
                         exceptionInfo->ContextRecord);
            return EXCEPTION_CONTINUE_SEARCH;
#endif
          }
        }
      }

#ifdef _WIN64
      // Special care for fast JNI field accessors.
      // jni_fast_Get<Primitive>Field can trap at certain pc's if a GC kicks
      // in and the heap gets shrunk before the field access.
      if (exception_code == EXCEPTION_ACCESS_VIOLATION) {
        address addr = JNI_FastGetField::find_slowcase_pc(pc);
        if (addr != (address)-1) {
          return Handle_Exception(exceptionInfo, addr);
        }
      }
#endif

#ifdef _WIN64
      // Windows will sometimes generate an access violation
      // when we call malloc.  Since we use VectoredExceptions
      // on 64 bit platforms, we see this exception.  We must
      // pass this exception on so Windows can recover.
      // We check to see if the pc of the fault is in NTDLL.DLL
      // if so, we pass control on to Windows for handling.
      if (UseVectoredExceptions && _addr_in_ntdll(pc)) return EXCEPTION_CONTINUE_SEARCH;
#endif

      // Stack overflow or null pointer exception in native code.
      report_error(t, exception_code, pc, exceptionInfo->ExceptionRecord,
                   exceptionInfo->ContextRecord);
      return EXCEPTION_CONTINUE_SEARCH;
    }

    if (in_java) {
      switch (exception_code) {
      case EXCEPTION_INT_DIVIDE_BY_ZERO:
        return Handle_Exception(exceptionInfo, SharedRuntime::continuation_for_implicit_exception(thread, pc, SharedRuntime::IMPLICIT_DIVIDE_BY_ZERO));

      case EXCEPTION_INT_OVERFLOW:
        return Handle_IDiv_Exception(exceptionInfo);

      } // switch
    }
#ifndef _WIN64
    if ((thread->thread_state() == _thread_in_Java) ||
        (thread->thread_state() == _thread_in_native) )
    {
      LONG result=Handle_FLT_Exception(exceptionInfo);
      if (result==EXCEPTION_CONTINUE_EXECUTION) return result;
    }
#endif //_WIN64
  }

  if (exception_code != EXCEPTION_BREAKPOINT) {
#ifndef _WIN64
    report_error(t, exception_code, pc, exceptionInfo->ExceptionRecord,
                 exceptionInfo->ContextRecord);
#else
    // Itanium Windows uses a VectoredExceptionHandler
    // Which means that C++ programatic exception handlers (try/except)
    // will get here.  Continue the search for the right except block if
    // the exception code is not a fatal code.
    switch ( exception_code ) {
      case EXCEPTION_ACCESS_VIOLATION:
      case EXCEPTION_STACK_OVERFLOW:
      case EXCEPTION_ILLEGAL_INSTRUCTION:
      case EXCEPTION_ILLEGAL_INSTRUCTION_2:
      case EXCEPTION_INT_OVERFLOW:
      case EXCEPTION_INT_DIVIDE_BY_ZERO:
      {  report_error(t, exception_code, pc, exceptionInfo->ExceptionRecord,
                       exceptionInfo->ContextRecord);
      }
        break;
      default:
        break;
    }
#endif
  }
  return EXCEPTION_CONTINUE_SEARCH;
}

#ifndef _WIN64
// Special care for fast JNI accessors.
// jni_fast_Get<Primitive>Field can trap at certain pc's if a GC kicks in and
// the heap gets shrunk before the field access.
// Need to install our own structured exception handler since native code may
// install its own.
LONG WINAPI fastJNIAccessorExceptionFilter(struct _EXCEPTION_POINTERS* exceptionInfo) {
  DWORD exception_code = exceptionInfo->ExceptionRecord->ExceptionCode;
  if (exception_code == EXCEPTION_ACCESS_VIOLATION) {
    address pc = (address) exceptionInfo->ContextRecord->Eip;
    address addr = JNI_FastGetField::find_slowcase_pc(pc);
    if (addr != (address)-1) {
      return Handle_Exception(exceptionInfo, addr);
    }
  }
  return EXCEPTION_CONTINUE_SEARCH;
}

#define DEFINE_FAST_GETFIELD(Return,Fieldname,Result) \
Return JNICALL jni_fast_Get##Result##Field_wrapper(JNIEnv *env, jobject obj, jfieldID fieldID) { \
  __try { \
    return (*JNI_FastGetField::jni_fast_Get##Result##Field_fp)(env, obj, fieldID); \
  } __except(fastJNIAccessorExceptionFilter((_EXCEPTION_POINTERS*)_exception_info())) { \
  } \
  return 0; \
}

DEFINE_FAST_GETFIELD(jboolean, bool,   Boolean)
DEFINE_FAST_GETFIELD(jbyte,    byte,   Byte)
DEFINE_FAST_GETFIELD(jchar,    char,   Char)
DEFINE_FAST_GETFIELD(jshort,   short,  Short)
DEFINE_FAST_GETFIELD(jint,     int,    Int)
DEFINE_FAST_GETFIELD(jlong,    long,   Long)
DEFINE_FAST_GETFIELD(jfloat,   float,  Float)
DEFINE_FAST_GETFIELD(jdouble,  double, Double)

address os::win32::fast_jni_accessor_wrapper(BasicType type) {
  switch (type) {
    case T_BOOLEAN: return (address)jni_fast_GetBooleanField_wrapper;
    case T_BYTE:    return (address)jni_fast_GetByteField_wrapper;
    case T_CHAR:    return (address)jni_fast_GetCharField_wrapper;
    case T_SHORT:   return (address)jni_fast_GetShortField_wrapper;
    case T_INT:     return (address)jni_fast_GetIntField_wrapper;
    case T_LONG:    return (address)jni_fast_GetLongField_wrapper;
    case T_FLOAT:   return (address)jni_fast_GetFloatField_wrapper;
    case T_DOUBLE:  return (address)jni_fast_GetDoubleField_wrapper;
    default:        ShouldNotReachHere();
  }
  return (address)-1;
}
#endif

// Virtual Memory

int os::vm_page_size() { return os::win32::vm_page_size(); }
int os::vm_allocation_granularity() {
  return os::win32::vm_allocation_granularity();
}

// Windows large page support is available on Windows 2003. In order to use
// large page memory, the administrator must first assign additional privilege
// to the user:
//   + select Control Panel -> Administrative Tools -> Local Security Policy
//   + select Local Policies -> User Rights Assignment
//   + double click "Lock pages in memory", add users and/or groups
//   + reboot
// Note the above steps are needed for administrator as well, as administrators
// by default do not have the privilege to lock pages in memory.
//
// Note about Windows 2003: although the API supports committing large page
// memory on a page-by-page basis and VirtualAlloc() returns success under this
// scenario, I found through experiment it only uses large page if the entire
// memory region is reserved and committed in a single VirtualAlloc() call.
// This makes Windows large page support more or less like Solaris ISM, in
// that the entire heap must be committed upfront. This probably will change
// in the future, if so the code below needs to be revisited.

#ifndef MEM_LARGE_PAGES
#define MEM_LARGE_PAGES 0x20000000
#endif

// GetLargePageMinimum is only available on Windows 2003. The other functions
// are available on NT but not on Windows 98/Me. We have to resolve them at
// runtime.
typedef SIZE_T (WINAPI *GetLargePageMinimum_func_type) (void);
typedef BOOL (WINAPI *AdjustTokenPrivileges_func_type)
             (HANDLE, BOOL, PTOKEN_PRIVILEGES, DWORD, PTOKEN_PRIVILEGES, PDWORD);
typedef BOOL (WINAPI *OpenProcessToken_func_type) (HANDLE, DWORD, PHANDLE);
typedef BOOL (WINAPI *LookupPrivilegeValue_func_type) (LPCTSTR, LPCTSTR, PLUID);

static GetLargePageMinimum_func_type   _GetLargePageMinimum;
static AdjustTokenPrivileges_func_type _AdjustTokenPrivileges;
static OpenProcessToken_func_type      _OpenProcessToken;
static LookupPrivilegeValue_func_type  _LookupPrivilegeValue;

static HINSTANCE _kernel32;
static HINSTANCE _advapi32;
static HANDLE    _hProcess;
static HANDLE    _hToken;

static size_t _large_page_size = 0;

static bool resolve_functions_for_large_page_init() {
  _kernel32 = LoadLibrary("kernel32.dll");
  if (_kernel32 == NULL) return false;

  _GetLargePageMinimum   = CAST_TO_FN_PTR(GetLargePageMinimum_func_type,
                            GetProcAddress(_kernel32, "GetLargePageMinimum"));
  if (_GetLargePageMinimum == NULL) return false;

  _advapi32 = LoadLibrary("advapi32.dll");
  if (_advapi32 == NULL) return false;

  _AdjustTokenPrivileges = CAST_TO_FN_PTR(AdjustTokenPrivileges_func_type,
                            GetProcAddress(_advapi32, "AdjustTokenPrivileges"));
  _OpenProcessToken      = CAST_TO_FN_PTR(OpenProcessToken_func_type,
                            GetProcAddress(_advapi32, "OpenProcessToken"));
  _LookupPrivilegeValue  = CAST_TO_FN_PTR(LookupPrivilegeValue_func_type,
                            GetProcAddress(_advapi32, "LookupPrivilegeValueA"));
  return _AdjustTokenPrivileges != NULL &&
         _OpenProcessToken      != NULL &&
         _LookupPrivilegeValue  != NULL;
}

static bool request_lock_memory_privilege() {
  _hProcess = OpenProcess(PROCESS_QUERY_INFORMATION, FALSE,
                                os::current_process_id());

  LUID luid;
  if (_hProcess != NULL &&
      _OpenProcessToken(_hProcess, TOKEN_ADJUST_PRIVILEGES, &_hToken) &&
      _LookupPrivilegeValue(NULL, "SeLockMemoryPrivilege", &luid)) {

    TOKEN_PRIVILEGES tp;
    tp.PrivilegeCount = 1;
    tp.Privileges[0].Luid = luid;
    tp.Privileges[0].Attributes = SE_PRIVILEGE_ENABLED;

    // AdjustTokenPrivileges() may return TRUE even when it couldn't change the
    // privilege. Check GetLastError() too. See MSDN document.
    if (_AdjustTokenPrivileges(_hToken, false, &tp, sizeof(tp), NULL, NULL) &&
        (GetLastError() == ERROR_SUCCESS)) {
      return true;
    }
  }

  return false;
}

static void cleanup_after_large_page_init() {
  _GetLargePageMinimum = NULL;
  _AdjustTokenPrivileges = NULL;
  _OpenProcessToken = NULL;
  _LookupPrivilegeValue = NULL;
  if (_kernel32) FreeLibrary(_kernel32);
  _kernel32 = NULL;
  if (_advapi32) FreeLibrary(_advapi32);
  _advapi32 = NULL;
  if (_hProcess) CloseHandle(_hProcess);
  _hProcess = NULL;
  if (_hToken) CloseHandle(_hToken);
  _hToken = NULL;
}

bool os::large_page_init() {
  if (!UseLargePages) return false;

  // print a warning if any large page related flag is specified on command line
  bool warn_on_failure = !FLAG_IS_DEFAULT(UseLargePages) ||
                         !FLAG_IS_DEFAULT(LargePageSizeInBytes);
  bool success = false;

# define WARN(msg) if (warn_on_failure) { warning(msg); }
  if (resolve_functions_for_large_page_init()) {
    if (request_lock_memory_privilege()) {
      size_t s = _GetLargePageMinimum();
      if (s) {
#if defined(IA32) || defined(AMD64)
        if (s > 4*M || LargePageSizeInBytes > 4*M) {
          WARN("JVM cannot use large pages bigger than 4mb.");
        } else {
#endif
          if (LargePageSizeInBytes && LargePageSizeInBytes % s == 0) {
            _large_page_size = LargePageSizeInBytes;
          } else {
            _large_page_size = s;
          }
          success = true;
#if defined(IA32) || defined(AMD64)
        }
#endif
      } else {
        WARN("Large page is not supported by the processor.");
      }
    } else {
      WARN("JVM cannot use large page memory because it does not have enough privilege to lock pages in memory.");
    }
  } else {
    WARN("Large page is not supported by the operating system.");
  }
#undef WARN

  const size_t default_page_size = (size_t) vm_page_size();
  if (success && _large_page_size > default_page_size) {
    _page_sizes[0] = _large_page_size;
    _page_sizes[1] = default_page_size;
    _page_sizes[2] = 0;
  }

  cleanup_after_large_page_init();
  return success;
}

// On win32, one cannot release just a part of reserved memory, it's an
// all or nothing deal.  When we split a reservation, we must break the
// reservation into two reservations.
void os::split_reserved_memory(char *base, size_t size, size_t split,
                              bool realloc) {
  if (size > 0) {
    release_memory(base, size);
    if (realloc) {
      reserve_memory(split, base);
    }
    if (size != split) {
      reserve_memory(size - split, base + split);
    }
  }
}

char* os::reserve_memory(size_t bytes, char* addr, size_t alignment_hint) {
  assert((size_t)addr % os::vm_allocation_granularity() == 0,
         "reserve alignment");
  assert(bytes % os::vm_allocation_granularity() == 0, "reserve block size");
  char* res = (char*)VirtualAlloc(addr, bytes, MEM_RESERVE,
                                  PAGE_EXECUTE_READWRITE);
  assert(res == NULL || addr == NULL || addr == res,
         "Unexpected address from reserve.");
  return res;
}

// Reserve memory at an arbitrary address, only if that area is
// available (and not reserved for something else).
char* os::attempt_reserve_memory_at(size_t bytes, char* requested_addr) {
  // Windows os::reserve_memory() fails of the requested address range is
  // not avilable.
  return reserve_memory(bytes, requested_addr);
}

size_t os::large_page_size() {
  return _large_page_size;
}

bool os::can_commit_large_page_memory() {
  // Windows only uses large page memory when the entire region is reserved
  // and committed in a single VirtualAlloc() call. This may change in the
  // future, but with Windows 2003 it's not possible to commit on demand.
  return false;
}

bool os::can_execute_large_page_memory() {
  return true;
}

char* os::reserve_memory_special(size_t bytes) {

  if (UseLargePagesIndividualAllocation) {
    if (TracePageSizes && Verbose) {
       tty->print_cr("Reserving large pages individually.");
    }
    char * p_buf;
    // first reserve enough address space in advance since we want to be
    // able to break a single contiguous virtual address range into multiple
    // large page commits but WS2003 does not allow reserving large page space
    // so we just use 4K pages for reserve, this gives us a legal contiguous
    // address space. then we will deallocate that reservation, and re alloc
    // using large pages
    const size_t size_of_reserve = bytes + _large_page_size;
    if (bytes > size_of_reserve) {
      // Overflowed.
      warning("Individually allocated large pages failed, "
        "use -XX:-UseLargePagesIndividualAllocation to turn off");
      return NULL;
    }
    p_buf = (char *) VirtualAlloc(NULL,
                                 size_of_reserve,  // size of Reserve
                                 MEM_RESERVE,
                                 PAGE_EXECUTE_READWRITE);
    // If reservation failed, return NULL
    if (p_buf == NULL) return NULL;

    release_memory(p_buf, bytes + _large_page_size);
    // round up to page boundary.  If the size_of_reserve did not
    // overflow and the reservation did not fail, this align up
    // should not overflow.
    p_buf = (char *) align_size_up((size_t)p_buf, _large_page_size);

    // now go through and allocate one page at a time until all bytes are
    // allocated
    size_t  bytes_remaining = align_size_up(bytes, _large_page_size);
    // An overflow of align_size_up() would have been caught above
    // in the calculation of size_of_reserve.
    char * next_alloc_addr = p_buf;

#ifdef ASSERT
    // Variable for the failure injection
    long ran_num = os::random();
    size_t fail_after = ran_num % bytes;
#endif

    while (bytes_remaining) {
      size_t bytes_to_rq = MIN2(bytes_remaining, _large_page_size);
      // Note allocate and commit
      char * p_new;

#ifdef ASSERT
      bool inject_error = LargePagesIndividualAllocationInjectError &&
          (bytes_remaining <= fail_after);
#else
      const bool inject_error = false;
#endif

      if (inject_error) {
        p_new = NULL;
      } else {
        p_new = (char *) VirtualAlloc(next_alloc_addr,
                                    bytes_to_rq,
                                    MEM_RESERVE | MEM_COMMIT | MEM_LARGE_PAGES,
                                    PAGE_EXECUTE_READWRITE);
      }

      if (p_new == NULL) {
        // Free any allocated pages
        if (next_alloc_addr > p_buf) {
          // Some memory was committed so release it.
          size_t bytes_to_release = bytes - bytes_remaining;
          release_memory(p_buf, bytes_to_release);
        }
#ifdef ASSERT
        if (UseLargePagesIndividualAllocation &&
            LargePagesIndividualAllocationInjectError) {
          if (TracePageSizes && Verbose) {
             tty->print_cr("Reserving large pages individually failed.");
          }
        }
#endif
        return NULL;
      }
      bytes_remaining -= bytes_to_rq;
      next_alloc_addr += bytes_to_rq;
    }

    return p_buf;

  } else {
    // normal policy just allocate it all at once
    DWORD flag = MEM_RESERVE | MEM_COMMIT | MEM_LARGE_PAGES;
    char * res = (char *)VirtualAlloc(NULL,
                                      bytes,
                                      flag,
                                      PAGE_EXECUTE_READWRITE);
    return res;
  }
}

bool os::release_memory_special(char* base, size_t bytes) {
  return release_memory(base, bytes);
}

void os::print_statistics() {
}

bool os::commit_memory(char* addr, size_t bytes) {
  if (bytes == 0) {
    // Don't bother the OS with noops.
    return true;
  }
  assert((size_t) addr % os::vm_page_size() == 0, "commit on page boundaries");
  assert(bytes % os::vm_page_size() == 0, "commit in page-sized chunks");
  // Don't attempt to print anything if the OS call fails. We're
  // probably low on resources, so the print itself may cause crashes.
  return VirtualAlloc(addr, bytes, MEM_COMMIT, PAGE_EXECUTE_READWRITE) != NULL;
}

bool os::commit_memory(char* addr, size_t size, size_t alignment_hint) {
  return commit_memory(addr, size);
}

bool os::uncommit_memory(char* addr, size_t bytes) {
  if (bytes == 0) {
    // Don't bother the OS with noops.
    return true;
  }
  assert((size_t) addr % os::vm_page_size() == 0, "uncommit on page boundaries");
  assert(bytes % os::vm_page_size() == 0, "uncommit in page-sized chunks");
  return VirtualFree(addr, bytes, MEM_DECOMMIT) != 0;
}

bool os::release_memory(char* addr, size_t bytes) {
  return VirtualFree(addr, 0, MEM_RELEASE) != 0;
}

// Set protections specified
bool os::protect_memory(char* addr, size_t bytes, ProtType prot,
                        bool is_committed) {
  unsigned int p = 0;
  switch (prot) {
  case MEM_PROT_NONE: p = PAGE_NOACCESS; break;
  case MEM_PROT_READ: p = PAGE_READONLY; break;
  case MEM_PROT_RW:   p = PAGE_READWRITE; break;
  case MEM_PROT_RWX:  p = PAGE_EXECUTE_READWRITE; break;
  default:
    ShouldNotReachHere();
  }

  DWORD old_status;

  // Strange enough, but on Win32 one can change protection only for committed
  // memory, not a big deal anyway, as bytes less or equal than 64K
  if (!is_committed && !commit_memory(addr, bytes)) {
    fatal("cannot commit protection page");
  }
  // One cannot use os::guard_memory() here, as on Win32 guard page
  // have different (one-shot) semantics, from MSDN on PAGE_GUARD:
  //
  // Pages in the region become guard pages. Any attempt to access a guard page
  // causes the system to raise a STATUS_GUARD_PAGE exception and turn off
  // the guard page status. Guard pages thus act as a one-time access alarm.
  return VirtualProtect(addr, bytes, p, &old_status) != 0;
}

bool os::guard_memory(char* addr, size_t bytes) {
  DWORD old_status;
  return VirtualProtect(addr, bytes, PAGE_READWRITE | PAGE_GUARD, &old_status) != 0;
}

bool os::unguard_memory(char* addr, size_t bytes) {
  DWORD old_status;
  return VirtualProtect(addr, bytes, PAGE_READWRITE, &old_status) != 0;
}

void os::realign_memory(char *addr, size_t bytes, size_t alignment_hint) { }
void os::free_memory(char *addr, size_t bytes)         { }
void os::numa_make_global(char *addr, size_t bytes)    { }
void os::numa_make_local(char *addr, size_t bytes, int lgrp_hint)    { }
bool os::numa_topology_changed()                       { return false; }
size_t os::numa_get_groups_num()                       { return 1; }
int os::numa_get_group_id()                            { return 0; }
size_t os::numa_get_leaf_groups(int *ids, size_t size) {
  if (size > 0) {
    ids[0] = 0;
    return 1;
  }
  return 0;
}

bool os::get_page_info(char *start, page_info* info) {
  return false;
}

char *os::scan_pages(char *start, char* end, page_info* page_expected, page_info* page_found) {
  return end;
}

char* os::non_memory_address_word() {
  // Must never look like an address returned by reserve_memory,
  // even in its subfields (as defined by the CPU immediate fields,
  // if the CPU splits constants across multiple instructions).
  return (char*)-1;
}

#define MAX_ERROR_COUNT 100
#define SYS_THREAD_ERROR 0xffffffffUL

void os::pd_start_thread(Thread* thread) {
  DWORD ret = ResumeThread(thread->osthread()->thread_handle());
  // Returns previous suspend state:
  // 0:  Thread was not suspended
  // 1:  Thread is running now
  // >1: Thread is still suspended.
  assert(ret != SYS_THREAD_ERROR, "StartThread failed"); // should propagate back
}

size_t os::read(int fd, void *buf, unsigned int nBytes) {
  return ::read(fd, buf, nBytes);
}

class HighResolutionInterval {
  // The default timer resolution seems to be 10 milliseconds.
  // (Where is this written down?)
  // If someone wants to sleep for only a fraction of the default,
  // then we set the timer resolution down to 1 millisecond for
  // the duration of their interval.
  // We carefully set the resolution back, since otherwise we
  // seem to incur an overhead (3%?) that we don't need.
  // CONSIDER: if ms is small, say 3, then we should run with a high resolution time.
  // Buf if ms is large, say 500, or 503, we should avoid the call to timeBeginPeriod().
  // Alternatively, we could compute the relative error (503/500 = .6%) and only use
  // timeBeginPeriod() if the relative error exceeded some threshold.
  // timeBeginPeriod() has been linked to problems with clock drift on win32 systems and
  // to decreased efficiency related to increased timer "tick" rates.  We want to minimize
  // (a) calls to timeBeginPeriod() and timeEndPeriod() and (b) time spent with high
  // resolution timers running.
private:
    jlong resolution;
public:
  HighResolutionInterval(jlong ms) {
    resolution = ms % 10L;
    if (resolution != 0) {
      MMRESULT result = timeBeginPeriod(1L);
    }
  }
  ~HighResolutionInterval() {
    if (resolution != 0) {
      MMRESULT result = timeEndPeriod(1L);
    }
    resolution = 0L;
  }
};

int os::sleep(Thread* thread, jlong ms, bool interruptable) {
  jlong limit = (jlong) MAXDWORD;

  while(ms > limit) {
    int res;
    if ((res = sleep(thread, limit, interruptable)) != OS_TIMEOUT)
      return res;
    ms -= limit;
  }

  assert(thread == Thread::current(),  "thread consistency check");
  OSThread* osthread = thread->osthread();
  OSThreadWaitState osts(osthread, false /* not Object.wait() */);
  int result;
  if (interruptable) {
    assert(thread->is_Java_thread(), "must be java thread");
    JavaThread *jt = (JavaThread *) thread;
    ThreadBlockInVM tbivm(jt);

    jt->set_suspend_equivalent();
    // cleared by handle_special_suspend_equivalent_condition() or
    // java_suspend_self() via check_and_wait_while_suspended()

    HANDLE events[1];
    events[0] = osthread->interrupt_event();
    HighResolutionInterval *phri=NULL;
    if(!ForceTimeHighResolution)
      phri = new HighResolutionInterval( ms );
    if (WaitForMultipleObjects(1, events, FALSE, (DWORD)ms) == WAIT_TIMEOUT) {
      result = OS_TIMEOUT;
    } else {
      ResetEvent(osthread->interrupt_event());
      osthread->set_interrupted(false);
      result = OS_INTRPT;
    }
    delete phri; //if it is NULL, harmless

    // were we externally suspended while we were waiting?
    jt->check_and_wait_while_suspended();
  } else {
    assert(!thread->is_Java_thread(), "must not be java thread");
    Sleep((long) ms);
    result = OS_TIMEOUT;
  }
  return result;
}

// Sleep forever; naked call to OS-specific sleep; use with CAUTION
void os::infinite_sleep() {
  while (true) {    // sleep forever ...
    Sleep(100000);  // ... 100 seconds at a time
  }
}

typedef BOOL (WINAPI * STTSignature)(void) ;

os::YieldResult os::NakedYield() {
  // Use either SwitchToThread() or Sleep(0)
  // Consider passing back the return value from SwitchToThread().
  // We use GetProcAddress() as ancient Win9X versions of windows doen't support SwitchToThread.
  // In that case we revert to Sleep(0).
  static volatile STTSignature stt = (STTSignature) 1 ;

  if (stt == ((STTSignature) 1)) {
    stt = (STTSignature) ::GetProcAddress (LoadLibrary ("Kernel32.dll"), "SwitchToThread") ;
    // It's OK if threads race during initialization as the operation above is idempotent.
  }
  if (stt != NULL) {
    return (*stt)() ? os::YIELD_SWITCHED : os::YIELD_NONEREADY ;
  } else {
    Sleep (0) ;
  }
  return os::YIELD_UNKNOWN ;
}

void os::yield() {  os::NakedYield(); }

void os::yield_all(int attempts) {
  // Yields to all threads, including threads with lower priorities
  Sleep(1);
}

// Win32 only gives you access to seven real priorities at a time,
// so we compress Java's ten down to seven.  It would be better
// if we dynamically adjusted relative priorities.

int os::java_to_os_priority[MaxPriority + 1] = {
  THREAD_PRIORITY_IDLE,                         // 0  Entry should never be used
  THREAD_PRIORITY_LOWEST,                       // 1  MinPriority
  THREAD_PRIORITY_LOWEST,                       // 2
  THREAD_PRIORITY_BELOW_NORMAL,                 // 3
  THREAD_PRIORITY_BELOW_NORMAL,                 // 4
  THREAD_PRIORITY_NORMAL,                       // 5  NormPriority
  THREAD_PRIORITY_NORMAL,                       // 6
  THREAD_PRIORITY_ABOVE_NORMAL,                 // 7
  THREAD_PRIORITY_ABOVE_NORMAL,                 // 8
  THREAD_PRIORITY_HIGHEST,                      // 9  NearMaxPriority
  THREAD_PRIORITY_HIGHEST                       // 10 MaxPriority
};

int prio_policy1[MaxPriority + 1] = {
  THREAD_PRIORITY_IDLE,                         // 0  Entry should never be used
  THREAD_PRIORITY_LOWEST,                       // 1  MinPriority
  THREAD_PRIORITY_LOWEST,                       // 2
  THREAD_PRIORITY_BELOW_NORMAL,                 // 3
  THREAD_PRIORITY_BELOW_NORMAL,                 // 4
  THREAD_PRIORITY_NORMAL,                       // 5  NormPriority
  THREAD_PRIORITY_ABOVE_NORMAL,                 // 6
  THREAD_PRIORITY_ABOVE_NORMAL,                 // 7
  THREAD_PRIORITY_HIGHEST,                      // 8
  THREAD_PRIORITY_HIGHEST,                      // 9  NearMaxPriority
  THREAD_PRIORITY_TIME_CRITICAL                 // 10 MaxPriority
};

static int prio_init() {
  // If ThreadPriorityPolicy is 1, switch tables
  if (ThreadPriorityPolicy == 1) {
    int i;
    for (i = 0; i < MaxPriority + 1; i++) {
      os::java_to_os_priority[i] = prio_policy1[i];
    }
  }
  return 0;
}

OSReturn os::set_native_priority(Thread* thread, int priority) {
  if (!UseThreadPriorities) return OS_OK;
  bool ret = SetThreadPriority(thread->osthread()->thread_handle(), priority) != 0;
  return ret ? OS_OK : OS_ERR;
}

OSReturn os::get_native_priority(const Thread* const thread, int* priority_ptr) {
  if ( !UseThreadPriorities ) {
    *priority_ptr = java_to_os_priority[NormPriority];
    return OS_OK;
  }
  int os_prio = GetThreadPriority(thread->osthread()->thread_handle());
  if (os_prio == THREAD_PRIORITY_ERROR_RETURN) {
    assert(false, "GetThreadPriority failed");
    return OS_ERR;
  }
  *priority_ptr = os_prio;
  return OS_OK;
}


// Hint to the underlying OS that a task switch would not be good.
// Void return because it's a hint and can fail.
void os::hint_no_preempt() {}

void os::interrupt(Thread* thread) {
  assert(!thread->is_Java_thread() || Thread::current() == thread || Threads_lock->owned_by_self(),
         "possibility of dangling Thread pointer");

  OSThread* osthread = thread->osthread();
  osthread->set_interrupted(true);
  // More than one thread can get here with the same value of osthread,
  // resulting in multiple notifications.  We do, however, want the store
  // to interrupted() to be visible to other threads before we post
  // the interrupt event.
  OrderAccess::release();
  SetEvent(osthread->interrupt_event());
  // For JSR166:  unpark after setting status
  if (thread->is_Java_thread())
    ((JavaThread*)thread)->parker()->unpark();

  ParkEvent * ev = thread->_ParkEvent ;
  if (ev != NULL) ev->unpark() ;

}


bool os::is_interrupted(Thread* thread, bool clear_interrupted) {
  assert(!thread->is_Java_thread() || Thread::current() == thread || Threads_lock->owned_by_self(),
         "possibility of dangling Thread pointer");

  OSThread* osthread = thread->osthread();
  bool interrupted;
  interrupted = osthread->interrupted();
  if (clear_interrupted == true) {
    osthread->set_interrupted(false);
    ResetEvent(osthread->interrupt_event());
  } // Otherwise leave the interrupted state alone

  return interrupted;
}

// Get's a pc (hint) for a running thread. Currently used only for profiling.
ExtendedPC os::get_thread_pc(Thread* thread) {
  CONTEXT context;
  context.ContextFlags = CONTEXT_CONTROL;
  HANDLE handle = thread->osthread()->thread_handle();
#ifdef _M_IA64
  assert(0, "Fix get_thread_pc");
  return ExtendedPC(NULL);
#else
  if (GetThreadContext(handle, &context)) {
#ifdef _M_AMD64
    return ExtendedPC((address) context.Rip);
#else
    return ExtendedPC((address) context.Eip);
#endif
  } else {
    return ExtendedPC(NULL);
  }
#endif
}

// GetCurrentThreadId() returns DWORD
intx os::current_thread_id()          { return GetCurrentThreadId(); }

static int _initial_pid = 0;

int os::current_process_id()
{
  return (_initial_pid ? _initial_pid : _getpid());
}

int    os::win32::_vm_page_size       = 0;
int    os::win32::_vm_allocation_granularity = 0;
int    os::win32::_processor_type     = 0;
// Processor level is not available on non-NT systems, use vm_version instead
int    os::win32::_processor_level    = 0;
julong os::win32::_physical_memory    = 0;
size_t os::win32::_default_stack_size = 0;

         intx os::win32::_os_thread_limit    = 0;
volatile intx os::win32::_os_thread_count    = 0;

bool   os::win32::_is_nt              = false;
bool   os::win32::_is_windows_2003    = false;


void os::win32::initialize_system_info() {
  SYSTEM_INFO si;
  GetSystemInfo(&si);
  _vm_page_size    = si.dwPageSize;
  _vm_allocation_granularity = si.dwAllocationGranularity;
  _processor_type  = si.dwProcessorType;
  _processor_level = si.wProcessorLevel;
  _processor_count = si.dwNumberOfProcessors;

  MEMORYSTATUS ms;
  // also returns dwAvailPhys (free physical memory bytes), dwTotalVirtual, dwAvailVirtual,
  // dwMemoryLoad (% of memory in use)
  GlobalMemoryStatus(&ms);
  _physical_memory = ms.dwTotalPhys;

  OSVERSIONINFO oi;
  oi.dwOSVersionInfoSize = sizeof(OSVERSIONINFO);
  GetVersionEx(&oi);
  switch(oi.dwPlatformId) {
    case VER_PLATFORM_WIN32_WINDOWS: _is_nt = false; break;
    case VER_PLATFORM_WIN32_NT:
      _is_nt = true;
      {
        int os_vers = oi.dwMajorVersion * 1000 + oi.dwMinorVersion;
        if (os_vers == 5002) {
          _is_windows_2003 = true;
        }
      }
      break;
    default: fatal("Unknown platform");
  }

  _default_stack_size = os::current_stack_size();
  assert(_default_stack_size > (size_t) _vm_page_size, "invalid stack size");
  assert((_default_stack_size & (_vm_page_size - 1)) == 0,
    "stack size not a multiple of page size");

  initialize_performance_counter();

  // Win95/Win98 scheduler bug work-around. The Win95/98 scheduler is
  // known to deadlock the system, if the VM issues to thread operations with
  // a too high frequency, e.g., such as changing the priorities.
  // The 6000 seems to work well - no deadlocks has been notices on the test
  // programs that we have seen experience this problem.
  if (!os::win32::is_nt()) {
    StarvationMonitorInterval = 6000;
  }
}


void os::win32::setmode_streams() {
  _setmode(_fileno(stdin), _O_BINARY);
  _setmode(_fileno(stdout), _O_BINARY);
  _setmode(_fileno(stderr), _O_BINARY);
}


int os::message_box(const char* title, const char* message) {
  int result = MessageBox(NULL, message, title,
                          MB_YESNO | MB_ICONERROR | MB_SYSTEMMODAL | MB_DEFAULT_DESKTOP_ONLY);
  return result == IDYES;
}

int os::allocate_thread_local_storage() {
  return TlsAlloc();
}


void os::free_thread_local_storage(int index) {
  TlsFree(index);
}


void os::thread_local_storage_at_put(int index, void* value) {
  TlsSetValue(index, value);
  assert(thread_local_storage_at(index) == value, "Just checking");
}


void* os::thread_local_storage_at(int index) {
  return TlsGetValue(index);
}


#ifndef PRODUCT
#ifndef _WIN64
// Helpers to check whether NX protection is enabled
int nx_exception_filter(_EXCEPTION_POINTERS *pex) {
  if (pex->ExceptionRecord->ExceptionCode == EXCEPTION_ACCESS_VIOLATION &&
      pex->ExceptionRecord->NumberParameters > 0 &&
      pex->ExceptionRecord->ExceptionInformation[0] ==
      EXCEPTION_INFO_EXEC_VIOLATION) {
    return EXCEPTION_EXECUTE_HANDLER;
  }
  return EXCEPTION_CONTINUE_SEARCH;
}

void nx_check_protection() {
  // If NX is enabled we'll get an exception calling into code on the stack
  char code[] = { (char)0xC3 }; // ret
  void *code_ptr = (void *)code;
  __try {
    __asm call code_ptr
  } __except(nx_exception_filter((_EXCEPTION_POINTERS*)_exception_info())) {
    tty->print_raw_cr("NX protection detected.");
  }
}
#endif // _WIN64
#endif // PRODUCT

// this is called _before_ the global arguments have been parsed
void os::init(void) {
  _initial_pid = _getpid();

  init_random(1234567);

  win32::initialize_system_info();
  win32::setmode_streams();
  init_page_sizes((size_t) win32::vm_page_size());

  // For better scalability on MP systems (must be called after initialize_system_info)
#ifndef PRODUCT
  if (is_MP()) {
    NoYieldsInMicrolock = true;
  }
#endif
  // This may be overridden later when argument processing is done.
  FLAG_SET_ERGO(bool, UseLargePagesIndividualAllocation,
    os::win32::is_windows_2003());

  // Initialize main_process and main_thread
  main_process = GetCurrentProcess();  // Remember main_process is a pseudo handle
 if (!DuplicateHandle(main_process, GetCurrentThread(), main_process,
                       &main_thread, THREAD_ALL_ACCESS, false, 0)) {
    fatal("DuplicateHandle failed\n");
  }
  main_thread_id = (int) GetCurrentThreadId();
}

// To install functions for atexit processing
extern "C" {
  static void perfMemory_exit_helper() {
    perfMemory_exit();
  }
}


// this is called _after_ the global arguments have been parsed
jint os::init_2(void) {
  // Allocate a single page and mark it as readable for safepoint polling
  address polling_page = (address)VirtualAlloc(NULL, os::vm_page_size(), MEM_RESERVE, PAGE_READONLY);
  guarantee( polling_page != NULL, "Reserve Failed for polling page");

  address return_page  = (address)VirtualAlloc(polling_page, os::vm_page_size(), MEM_COMMIT, PAGE_READONLY);
  guarantee( return_page != NULL, "Commit Failed for polling page");

  os::set_polling_page( polling_page );

#ifndef PRODUCT
  if( Verbose && PrintMiscellaneous )
    tty->print("[SafePoint Polling address: " INTPTR_FORMAT "]\n", (intptr_t)polling_page);
#endif

  if (!UseMembar) {
    address mem_serialize_page = (address)VirtualAlloc(NULL, os::vm_page_size(), MEM_RESERVE, PAGE_EXECUTE_READWRITE);
    guarantee( mem_serialize_page != NULL, "Reserve Failed for memory serialize page");

    return_page  = (address)VirtualAlloc(mem_serialize_page, os::vm_page_size(), MEM_COMMIT, PAGE_EXECUTE_READWRITE);
    guarantee( return_page != NULL, "Commit Failed for memory serialize page");

    os::set_memory_serialize_page( mem_serialize_page );

#ifndef PRODUCT
    if(Verbose && PrintMiscellaneous)
      tty->print("[Memory Serialize  Page address: " INTPTR_FORMAT "]\n", (intptr_t)mem_serialize_page);
#endif
}

  FLAG_SET_DEFAULT(UseLargePages, os::large_page_init());

  // Setup Windows Exceptions

  // On Itanium systems, Structured Exception Handling does not
  // work since stack frames must be walkable by the OS.  Since
  // much of our code is dynamically generated, and we do not have
  // proper unwind .xdata sections, the system simply exits
  // rather than delivering the exception.  To work around
  // this we use VectorExceptions instead.
#ifdef _WIN64
  if (UseVectoredExceptions) {
    topLevelVectoredExceptionHandler = AddVectoredExceptionHandler( 1, topLevelExceptionFilter);
  }
#endif

  // for debugging float code generation bugs
  if (ForceFloatExceptions) {
#ifndef  _WIN64
    static long fp_control_word = 0;
    __asm { fstcw fp_control_word }
    // see Intel PPro Manual, Vol. 2, p 7-16
    const long precision = 0x20;
    const long underflow = 0x10;
    const long overflow  = 0x08;
    const long zero_div  = 0x04;
    const long denorm    = 0x02;
    const long invalid   = 0x01;
    fp_control_word |= invalid;
    __asm { fldcw fp_control_word }
#endif
  }

  // Initialize HPI.
  jint hpi_result = hpi::initialize();
  if (hpi_result != JNI_OK) { return hpi_result; }

  // If stack_commit_size is 0, windows will reserve the default size,
  // but only commit a small portion of it.
  size_t stack_commit_size = round_to(ThreadStackSize*K, os::vm_page_size());
  size_t default_reserve_size = os::win32::default_stack_size();
  size_t actual_reserve_size = stack_commit_size;
  if (stack_commit_size < default_reserve_size) {
    // If stack_commit_size == 0, we want this too
    actual_reserve_size = default_reserve_size;
  }

  JavaThread::set_stack_size_at_create(stack_commit_size);

  // Calculate theoretical max. size of Threads to guard gainst artifical
  // out-of-memory situations, where all available address-space has been
  // reserved by thread stacks.
  assert(actual_reserve_size != 0, "Must have a stack");

  // Calculate the thread limit when we should start doing Virtual Memory
  // banging. Currently when the threads will have used all but 200Mb of space.
  //
  // TODO: consider performing a similar calculation for commit size instead
  // as reserve size, since on a 64-bit platform we'll run into that more
  // often than running out of virtual memory space.  We can use the
  // lower value of the two calculations as the os_thread_limit.
  size_t max_address_space = ((size_t)1 << (BitsPerWord - 1)) - (200 * K * K);
  win32::_os_thread_limit = (intx)(max_address_space / actual_reserve_size);

  // at exit methods are called in the reverse order of their registration.
  // there is no limit to the number of functions registered. atexit does
  // not set errno.

  if (PerfAllowAtExitRegistration) {
    // only register atexit functions if PerfAllowAtExitRegistration is set.
    // atexit functions can be delayed until process exit time, which
    // can be problematic for embedded VM situations. Embedded VMs should
    // call DestroyJavaVM() to assure that VM resources are released.

    // note: perfMemory_exit_helper atexit function may be removed in
    // the future if the appropriate cleanup code can be added to the
    // VM_Exit VMOperation's doit method.
    if (atexit(perfMemory_exit_helper) != 0) {
      warning("os::init_2 atexit(perfMemory_exit_helper) failed");
    }
  }

  // initialize PSAPI or ToolHelp for fatal error handler
  if (win32::is_nt()) _init_psapi();
  else _init_toolhelp();

#ifndef _WIN64
  // Print something if NX is enabled (win32 on AMD64)
  NOT_PRODUCT(if (PrintMiscellaneous && Verbose) nx_check_protection());
#endif

  // initialize thread priority policy
  prio_init();

  if (UseNUMA && !ForceNUMA) {
    UseNUMA = false; // Currently unsupported.
  }

  return JNI_OK;
}


// Mark the polling page as unreadable
void os::make_polling_page_unreadable(void) {
  DWORD old_status;
  if( !VirtualProtect((char *)_polling_page, os::vm_page_size(), PAGE_NOACCESS, &old_status) )
    fatal("Could not disable polling page");
};

// Mark the polling page as readable
void os::make_polling_page_readable(void) {
  DWORD old_status;
  if( !VirtualProtect((char *)_polling_page, os::vm_page_size(), PAGE_READONLY, &old_status) )
    fatal("Could not enable polling page");
};


int os::stat(const char *path, struct stat *sbuf) {
  char pathbuf[MAX_PATH];
  if (strlen(path) > MAX_PATH - 1) {
    errno = ENAMETOOLONG;
    return -1;
  }
  hpi::native_path(strcpy(pathbuf, path));
  int ret = ::stat(pathbuf, sbuf);
  if (sbuf != NULL && UseUTCFileTimestamp) {
    // Fix for 6539723.  st_mtime returned from stat() is dependent on
    // the system timezone and so can return different values for the
    // same file if/when daylight savings time changes.  This adjustment
    // makes sure the same timestamp is returned regardless of the TZ.
    //
    // See:
    // http://msdn.microsoft.com/library/
    //   default.asp?url=/library/en-us/sysinfo/base/
    //   time_zone_information_str.asp
    // and
    // http://msdn.microsoft.com/library/default.asp?url=
    //   /library/en-us/sysinfo/base/settimezoneinformation.asp
    //
    // NOTE: there is a insidious bug here:  If the timezone is changed
    // after the call to stat() but before 'GetTimeZoneInformation()', then
    // the adjustment we do here will be wrong and we'll return the wrong
    // value (which will likely end up creating an invalid class data
    // archive).  Absent a better API for this, or some time zone locking
    // mechanism, we'll have to live with this risk.
    TIME_ZONE_INFORMATION tz;
    DWORD tzid = GetTimeZoneInformation(&tz);
    int daylightBias =
      (tzid == TIME_ZONE_ID_DAYLIGHT) ?  tz.DaylightBias : tz.StandardBias;
    sbuf->st_mtime += (tz.Bias + daylightBias) * 60;
  }
  return ret;
}


#define FT2INT64(ft) \
  ((jlong)((jlong)(ft).dwHighDateTime << 32 | (julong)(ft).dwLowDateTime))


// current_thread_cpu_time(bool) and thread_cpu_time(Thread*, bool)
// are used by JVM M&M and JVMTI to get user+sys or user CPU time
// of a thread.
//
// current_thread_cpu_time() and thread_cpu_time(Thread*) returns
// the fast estimate available on the platform.

// current_thread_cpu_time() is not optimized for Windows yet
jlong os::current_thread_cpu_time() {
  // return user + sys since the cost is the same
  return os::thread_cpu_time(Thread::current(), true /* user+sys */);
}

jlong os::thread_cpu_time(Thread* thread) {
  // consistent with what current_thread_cpu_time() returns.
  return os::thread_cpu_time(thread, true /* user+sys */);
}

jlong os::current_thread_cpu_time(bool user_sys_cpu_time) {
  return os::thread_cpu_time(Thread::current(), user_sys_cpu_time);
}

jlong os::thread_cpu_time(Thread* thread, bool user_sys_cpu_time) {
  // This code is copy from clasic VM -> hpi::sysThreadCPUTime
  // If this function changes, os::is_thread_cpu_time_supported() should too
  if (os::win32::is_nt()) {
    FILETIME CreationTime;
    FILETIME ExitTime;
    FILETIME KernelTime;
    FILETIME UserTime;

    if ( GetThreadTimes(thread->osthread()->thread_handle(),
                    &CreationTime, &ExitTime, &KernelTime, &UserTime) == 0)
      return -1;
    else
      if (user_sys_cpu_time) {
        return (FT2INT64(UserTime) + FT2INT64(KernelTime)) * 100;
      } else {
        return FT2INT64(UserTime) * 100;
      }
  } else {
    return (jlong) timeGetTime() * 1000000;
  }
}

void os::current_thread_cpu_time_info(jvmtiTimerInfo *info_ptr) {
  info_ptr->max_value = ALL_64_BITS;        // the max value -- all 64 bits
  info_ptr->may_skip_backward = false;      // GetThreadTimes returns absolute time
  info_ptr->may_skip_forward = false;       // GetThreadTimes returns absolute time
  info_ptr->kind = JVMTI_TIMER_TOTAL_CPU;   // user+system time is returned
}

void os::thread_cpu_time_info(jvmtiTimerInfo *info_ptr) {
  info_ptr->max_value = ALL_64_BITS;        // the max value -- all 64 bits
  info_ptr->may_skip_backward = false;      // GetThreadTimes returns absolute time
  info_ptr->may_skip_forward = false;       // GetThreadTimes returns absolute time
  info_ptr->kind = JVMTI_TIMER_TOTAL_CPU;   // user+system time is returned
}

bool os::is_thread_cpu_time_supported() {
  // see os::thread_cpu_time
  if (os::win32::is_nt()) {
    FILETIME CreationTime;
    FILETIME ExitTime;
    FILETIME KernelTime;
    FILETIME UserTime;

    if ( GetThreadTimes(GetCurrentThread(),
                    &CreationTime, &ExitTime, &KernelTime, &UserTime) == 0)
      return false;
    else
      return true;
  } else {
    return false;
  }
}

// Windows does't provide a loadavg primitive so this is stubbed out for now.
// It does have primitives (PDH API) to get CPU usage and run queue length.
// "\\Processor(_Total)\\% Processor Time", "\\System\\Processor Queue Length"
// If we wanted to implement loadavg on Windows, we have a few options:
//
// a) Query CPU usage and run queue length and "fake" an answer by
//    returning the CPU usage if it's under 100%, and the run queue
//    length otherwise.  It turns out that querying is pretty slow
//    on Windows, on the order of 200 microseconds on a fast machine.
//    Note that on the Windows the CPU usage value is the % usage
//    since the last time the API was called (and the first call
//    returns 100%), so we'd have to deal with that as well.
//
// b) Sample the "fake" answer using a sampling thread and store
//    the answer in a global variable.  The call to loadavg would
//    just return the value of the global, avoiding the slow query.
//
// c) Sample a better answer using exponential decay to smooth the
//    value.  This is basically the algorithm used by UNIX kernels.
//
// Note that sampling thread starvation could affect both (b) and (c).
int os::loadavg(double loadavg[], int nelem) {
  return -1;
}


// DontYieldALot=false by default: dutifully perform all yields as requested by JVM_Yield()
bool os::dont_yield() {
  return DontYieldALot;
}

// Is a (classpath) directory empty?
bool os::dir_is_empty(const char* path) {
  WIN32_FIND_DATA fd;
  HANDLE f = FindFirstFile(path, &fd);
  if (f == INVALID_HANDLE_VALUE) {
    return true;
  }
  FindClose(f);
  return false;
}

// create binary file, rewriting existing file if required
int os::create_binary_file(const char* path, bool rewrite_existing) {
  int oflags = _O_CREAT | _O_WRONLY | _O_BINARY;
  if (!rewrite_existing) {
    oflags |= _O_EXCL;
  }
  return ::open(path, oflags, _S_IREAD | _S_IWRITE);
}

// return current position of file pointer
jlong os::current_file_offset(int fd) {
  return (jlong)::_lseeki64(fd, (__int64)0L, SEEK_CUR);
}

// move file pointer to the specified offset
jlong os::seek_to_file_offset(int fd, jlong offset) {
  return (jlong)::_lseeki64(fd, (__int64)offset, SEEK_SET);
}


// Map a block of memory.
char* os::map_memory(int fd, const char* file_name, size_t file_offset,
                     char *addr, size_t bytes, bool read_only,
                     bool allow_exec) {
  HANDLE hFile;
  char* base;

  hFile = CreateFile(file_name, GENERIC_READ, FILE_SHARE_READ, NULL,
                     OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, NULL);
  if (hFile == NULL) {
    if (PrintMiscellaneous && Verbose) {
      DWORD err = GetLastError();
      tty->print_cr("CreateFile() failed: GetLastError->%ld.");
    }
    return NULL;
  }

  if (allow_exec) {
    // CreateFileMapping/MapViewOfFileEx can't map executable memory
    // unless it comes from a PE image (which the shared archive is not.)
    // Even VirtualProtect refuses to give execute access to mapped memory
    // that was not previously executable.
    //
    // Instead, stick the executable region in anonymous memory.  Yuck.
    // Penalty is that ~4 pages will not be shareable - in the future
    // we might consider DLLizing the shared archive with a proper PE
    // header so that mapping executable + sharing is possible.

    base = (char*) VirtualAlloc(addr, bytes, MEM_COMMIT | MEM_RESERVE,
                                PAGE_READWRITE);
    if (base == NULL) {
      if (PrintMiscellaneous && Verbose) {
        DWORD err = GetLastError();
        tty->print_cr("VirtualAlloc() failed: GetLastError->%ld.", err);
      }
      CloseHandle(hFile);
      return NULL;
    }

    DWORD bytes_read;
    OVERLAPPED overlapped;
    overlapped.Offset = (DWORD)file_offset;
    overlapped.OffsetHigh = 0;
    overlapped.hEvent = NULL;
    // ReadFile guarantees that if the return value is true, the requested
    // number of bytes were read before returning.
    bool res = ReadFile(hFile, base, (DWORD)bytes, &bytes_read, &overlapped) != 0;
    if (!res) {
      if (PrintMiscellaneous && Verbose) {
        DWORD err = GetLastError();
        tty->print_cr("ReadFile() failed: GetLastError->%ld.", err);
      }
      release_memory(base, bytes);
      CloseHandle(hFile);
      return NULL;
    }
  } else {
    HANDLE hMap = CreateFileMapping(hFile, NULL, PAGE_WRITECOPY, 0, 0,
                                    NULL /*file_name*/);
    if (hMap == NULL) {
      if (PrintMiscellaneous && Verbose) {
        DWORD err = GetLastError();
        tty->print_cr("CreateFileMapping() failed: GetLastError->%ld.");
      }
      CloseHandle(hFile);
      return NULL;
    }

    DWORD access = read_only ? FILE_MAP_READ : FILE_MAP_COPY;
    base = (char*)MapViewOfFileEx(hMap, access, 0, (DWORD)file_offset,
                                  (DWORD)bytes, addr);
    if (base == NULL) {
      if (PrintMiscellaneous && Verbose) {
        DWORD err = GetLastError();
        tty->print_cr("MapViewOfFileEx() failed: GetLastError->%ld.", err);
      }
      CloseHandle(hMap);
      CloseHandle(hFile);
      return NULL;
    }

    if (CloseHandle(hMap) == 0) {
      if (PrintMiscellaneous && Verbose) {
        DWORD err = GetLastError();
        tty->print_cr("CloseHandle(hMap) failed: GetLastError->%ld.", err);
      }
      CloseHandle(hFile);
      return base;
    }
  }

  if (allow_exec) {
    DWORD old_protect;
    DWORD exec_access = read_only ? PAGE_EXECUTE_READ : PAGE_EXECUTE_READWRITE;
    bool res = VirtualProtect(base, bytes, exec_access, &old_protect) != 0;

    if (!res) {
      if (PrintMiscellaneous && Verbose) {
        DWORD err = GetLastError();
        tty->print_cr("VirtualProtect() failed: GetLastError->%ld.", err);
      }
      // Don't consider this a hard error, on IA32 even if the
      // VirtualProtect fails, we should still be able to execute
      CloseHandle(hFile);
      return base;
    }
  }

  if (CloseHandle(hFile) == 0) {
    if (PrintMiscellaneous && Verbose) {
      DWORD err = GetLastError();
      tty->print_cr("CloseHandle(hFile) failed: GetLastError->%ld.", err);
    }
    return base;
  }

  return base;
}


// Remap a block of memory.
char* os::remap_memory(int fd, const char* file_name, size_t file_offset,
                       char *addr, size_t bytes, bool read_only,
                       bool allow_exec) {
  // This OS does not allow existing memory maps to be remapped so we
  // have to unmap the memory before we remap it.
  if (!os::unmap_memory(addr, bytes)) {
    return NULL;
  }

  // There is a very small theoretical window between the unmap_memory()
  // call above and the map_memory() call below where a thread in native
  // code may be able to access an address that is no longer mapped.

  return os::map_memory(fd, file_name, file_offset, addr, bytes, read_only,
                        allow_exec);
}


// Unmap a block of memory.
// Returns true=success, otherwise false.

bool os::unmap_memory(char* addr, size_t bytes) {
  BOOL result = UnmapViewOfFile(addr);
  if (result == 0) {
    if (PrintMiscellaneous && Verbose) {
      DWORD err = GetLastError();
      tty->print_cr("UnmapViewOfFile() failed: GetLastError->%ld.", err);
    }
    return false;
  }
  return true;
}

void os::pause() {
  char filename[MAX_PATH];
  if (PauseAtStartupFile && PauseAtStartupFile[0]) {
    jio_snprintf(filename, MAX_PATH, PauseAtStartupFile);
  } else {
    jio_snprintf(filename, MAX_PATH, "./vm.paused.%d", current_process_id());
  }

  int fd = ::open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0666);
  if (fd != -1) {
    struct stat buf;
    close(fd);
    while (::stat(filename, &buf) == 0) {
      Sleep(100);
    }
  } else {
    jio_fprintf(stderr,
      "Could not open pause file '%s', continuing immediately.\n", filename);
  }
}

// An Event wraps a win32 "CreateEvent" kernel handle.
//
// We have a number of choices regarding "CreateEvent" win32 handle leakage:
//
// 1:  When a thread dies return the Event to the EventFreeList, clear the ParkHandle
//     field, and call CloseHandle() on the win32 event handle.  Unpark() would
//     need to be modified to tolerate finding a NULL (invalid) win32 event handle.
//     In addition, an unpark() operation might fetch the handle field, but the
//     event could recycle between the fetch and the SetEvent() operation.
//     SetEvent() would either fail because the handle was invalid, or inadvertently work,
//     as the win32 handle value had been recycled.  In an ideal world calling SetEvent()
//     on an stale but recycled handle would be harmless, but in practice this might
//     confuse other non-Sun code, so it's not a viable approach.
//
// 2:  Once a win32 event handle is associated with an Event, it remains associated
//     with the Event.  The event handle is never closed.  This could be construed
//     as handle leakage, but only up to the maximum # of threads that have been extant
//     at any one time.  This shouldn't be an issue, as windows platforms typically
//     permit a process to have hundreds of thousands of open handles.
//
// 3:  Same as (1), but periodically, at stop-the-world time, rundown the EventFreeList
//     and release unused handles.
//
// 4:  Add a CRITICAL_SECTION to the Event to protect LD+SetEvent from LD;ST(null);CloseHandle.
//     It's not clear, however, that we wouldn't be trading one type of leak for another.
//
// 5.  Use an RCU-like mechanism (Read-Copy Update).
//     Or perhaps something similar to Maged Michael's "Hazard pointers".
//
// We use (2).
//
// TODO-FIXME:
// 1.  Reconcile Doug's JSR166 j.u.c park-unpark with the objectmonitor implementation.
// 2.  Consider wrapping the WaitForSingleObject(Ex) calls in SEH try/finally blocks
//     to recover from (or at least detect) the dreaded Windows 841176 bug.
// 3.  Collapse the interrupt_event, the JSR166 parker event, and the objectmonitor ParkEvent
//     into a single win32 CreateEvent() handle.
//
// _Event transitions in park()
//   -1 => -1 : illegal
//    1 =>  0 : pass - return immediately
//    0 => -1 : block
//
// _Event serves as a restricted-range semaphore :
//    -1 : thread is blocked
//     0 : neutral  - thread is running or ready
//     1 : signaled - thread is running or ready
//
// Another possible encoding of _Event would be
// with explicit "PARKED" and "SIGNALED" bits.

int os::PlatformEvent::park (jlong Millis) {
    guarantee (_ParkHandle != NULL , "Invariant") ;
    guarantee (Millis > 0          , "Invariant") ;
    int v ;

    // CONSIDER: defer assigning a CreateEvent() handle to the Event until
    // the initial park() operation.

    for (;;) {
        v = _Event ;
        if (Atomic::cmpxchg (v-1, &_Event, v) == v) break ;
    }
    guarantee ((v == 0) || (v == 1), "invariant") ;
    if (v != 0) return OS_OK ;

    // Do this the hard way by blocking ...
    // TODO: consider a brief spin here, gated on the success of recent
    // spin attempts by this thread.
    //
    // We decompose long timeouts into series of shorter timed waits.
    // Evidently large timo values passed in WaitForSingleObject() are problematic on some
    // versions of Windows.  See EventWait() for details.  This may be superstition.  Or not.
    // We trust the WAIT_TIMEOUT indication and don't track the elapsed wait time
    // with os::javaTimeNanos().  Furthermore, we assume that spurious returns from
    // ::WaitForSingleObject() caused by latent ::setEvent() operations will tend
    // to happen early in the wait interval.  Specifically, after a spurious wakeup (rv ==
    // WAIT_OBJECT_0 but _Event is still < 0) we don't bother to recompute Millis to compensate
    // for the already waited time.  This policy does not admit any new outcomes.
    // In the future, however, we might want to track the accumulated wait time and
    // adjust Millis accordingly if we encounter a spurious wakeup.

    const int MAXTIMEOUT = 0x10000000 ;
    DWORD rv = WAIT_TIMEOUT ;
    while (_Event < 0 && Millis > 0) {
       DWORD prd = Millis ;     // set prd = MAX (Millis, MAXTIMEOUT)
       if (Millis > MAXTIMEOUT) {
          prd = MAXTIMEOUT ;
       }
       rv = ::WaitForSingleObject (_ParkHandle, prd) ;
       assert (rv == WAIT_OBJECT_0 || rv == WAIT_TIMEOUT, "WaitForSingleObject failed") ;
       if (rv == WAIT_TIMEOUT) {
           Millis -= prd ;
       }
    }
    v = _Event ;
    _Event = 0 ;
    OrderAccess::fence() ;
    // If we encounter a nearly simultanous timeout expiry and unpark()
    // we return OS_OK indicating we awoke via unpark().
    // Implementor's license -- returning OS_TIMEOUT would be equally valid, however.
    return (v >= 0) ? OS_OK : OS_TIMEOUT ;
}

void os::PlatformEvent::park () {
    guarantee (_ParkHandle != NULL, "Invariant") ;
    // Invariant: Only the thread associated with the Event/PlatformEvent
    // may call park().
    int v ;
    for (;;) {
        v = _Event ;
        if (Atomic::cmpxchg (v-1, &_Event, v) == v) break ;
    }
    guarantee ((v == 0) || (v == 1), "invariant") ;
    if (v != 0) return ;

    // Do this the hard way by blocking ...
    // TODO: consider a brief spin here, gated on the success of recent
    // spin attempts by this thread.
    while (_Event < 0) {
       DWORD rv = ::WaitForSingleObject (_ParkHandle, INFINITE) ;
       assert (rv == WAIT_OBJECT_0, "WaitForSingleObject failed") ;
    }

    // Usually we'll find _Event == 0 at this point, but as
    // an optional optimization we clear it, just in case can
    // multiple unpark() operations drove _Event up to 1.
    _Event = 0 ;
    OrderAccess::fence() ;
    guarantee (_Event >= 0, "invariant") ;
}

void os::PlatformEvent::unpark() {
  guarantee (_ParkHandle != NULL, "Invariant") ;
  int v ;
  for (;;) {
      v = _Event ;      // Increment _Event if it's < 1.
      if (v > 0) {
         // If it's already signaled just return.
         // The LD of _Event could have reordered or be satisfied
         // by a read-aside from this processor's write buffer.
         // To avoid problems execute a barrier and then
         // ratify the value.  A degenerate CAS() would also work.
         // Viz., CAS (v+0, &_Event, v) == v).
         OrderAccess::fence() ;
         if (_Event == v) return ;
         continue ;
      }
      if (Atomic::cmpxchg (v+1, &_Event, v) == v) break ;
  }
  if (v < 0) {
     ::SetEvent (_ParkHandle) ;
  }
}


// JSR166
// -------------------------------------------------------

/*
 * The Windows implementation of Park is very straightforward: Basic
 * operations on Win32 Events turn out to have the right semantics to
 * use them directly. We opportunistically resuse the event inherited
 * from Monitor.
 */


void Parker::park(bool isAbsolute, jlong time) {
  guarantee (_ParkEvent != NULL, "invariant") ;
  // First, demultiplex/decode time arguments
  if (time < 0) { // don't wait
    return;
  }
  else if (time == 0) {
    time = INFINITE;
  }
  else if  (isAbsolute) {
    time -= os::javaTimeMillis(); // convert to relative time
    if (time <= 0) // already elapsed
      return;
  }
  else { // relative
    time /= 1000000; // Must coarsen from nanos to millis
    if (time == 0)   // Wait for the minimal time unit if zero
      time = 1;
  }

  JavaThread* thread = (JavaThread*)(Thread::current());
  assert(thread->is_Java_thread(), "Must be JavaThread");
  JavaThread *jt = (JavaThread *)thread;

  // Don't wait if interrupted or already triggered
  if (Thread::is_interrupted(thread, false) ||
    WaitForSingleObject(_ParkEvent, 0) == WAIT_OBJECT_0) {
    ResetEvent(_ParkEvent);
    return;
  }
  else {
    ThreadBlockInVM tbivm(jt);
    OSThreadWaitState osts(thread->osthread(), false /* not Object.wait() */);
    jt->set_suspend_equivalent();

    WaitForSingleObject(_ParkEvent,  time);
    ResetEvent(_ParkEvent);

    // If externally suspended while waiting, re-suspend
    if (jt->handle_special_suspend_equivalent_condition()) {
      jt->java_suspend_self();
    }
  }
}

void Parker::unpark() {
  guarantee (_ParkEvent != NULL, "invariant") ;
  SetEvent(_ParkEvent);
}

// Run the specified command in a separate process. Return its exit value,
// or -1 on failure (e.g. can't create a new process).
int os::fork_and_exec(char* cmd) {
  STARTUPINFO si;
  PROCESS_INFORMATION pi;

  memset(&si, 0, sizeof(si));
  si.cb = sizeof(si);
  memset(&pi, 0, sizeof(pi));
  BOOL rslt = CreateProcess(NULL,   // executable name - use command line
                            cmd,    // command line
                            NULL,   // process security attribute
                            NULL,   // thread security attribute
                            TRUE,   // inherits system handles
                            0,      // no creation flags
                            NULL,   // use parent's environment block
                            NULL,   // use parent's starting directory
                            &si,    // (in) startup information
                            &pi);   // (out) process information

  if (rslt) {
    // Wait until child process exits.
    WaitForSingleObject(pi.hProcess, INFINITE);

    DWORD exit_code;
    GetExitCodeProcess(pi.hProcess, &exit_code);

    // Close process and thread handles.
    CloseHandle(pi.hProcess);
    CloseHandle(pi.hThread);

    return (int)exit_code;
  } else {
    return -1;
  }
}

//--------------------------------------------------------------------------------------------------
// Non-product code

static int mallocDebugIntervalCounter = 0;
static int mallocDebugCounter = 0;
bool os::check_heap(bool force) {
  if (++mallocDebugCounter < MallocVerifyStart && !force) return true;
  if (++mallocDebugIntervalCounter >= MallocVerifyInterval || force) {
    // Note: HeapValidate executes two hardware breakpoints when it finds something
    // wrong; at these points, eax contains the address of the offending block (I think).
    // To get to the exlicit error message(s) below, just continue twice.
    HANDLE heap = GetProcessHeap();
    { HeapLock(heap);
      PROCESS_HEAP_ENTRY phe;
      phe.lpData = NULL;
      while (HeapWalk(heap, &phe) != 0) {
        if ((phe.wFlags & PROCESS_HEAP_ENTRY_BUSY) &&
            !HeapValidate(heap, 0, phe.lpData)) {
          tty->print_cr("C heap has been corrupted (time: %d allocations)", mallocDebugCounter);
          tty->print_cr("corrupted block near address %#x, length %d", phe.lpData, phe.cbData);
          fatal("corrupted C heap");
        }
      }
      int err = GetLastError();
      if (err != ERROR_NO_MORE_ITEMS && err != ERROR_CALL_NOT_IMPLEMENTED) {
        fatal1("heap walk aborted with error %d", err);
      }
      HeapUnlock(heap);
    }
    mallocDebugIntervalCounter = 0;
  }
  return true;
}


#ifndef PRODUCT
bool os::find(address addr) {
  // Nothing yet
  return false;
}
#endif

LONG WINAPI os::win32::serialize_fault_filter(struct _EXCEPTION_POINTERS* e) {
  DWORD exception_code = e->ExceptionRecord->ExceptionCode;

  if ( exception_code == EXCEPTION_ACCESS_VIOLATION ) {
    JavaThread* thread = (JavaThread*)ThreadLocalStorage::get_thread_slow();
    PEXCEPTION_RECORD exceptionRecord = e->ExceptionRecord;
    address addr = (address) exceptionRecord->ExceptionInformation[1];

    if (os::is_memory_serialize_page(thread, addr))
      return EXCEPTION_CONTINUE_EXECUTION;
  }

  return EXCEPTION_CONTINUE_SEARCH;
}

static int getLastErrorString(char *buf, size_t len)
{
    long errval;

    if ((errval = GetLastError()) != 0)
    {
      /* DOS error */
      size_t n = (size_t)FormatMessage(
            FORMAT_MESSAGE_FROM_SYSTEM|FORMAT_MESSAGE_IGNORE_INSERTS,
            NULL,
            errval,
            0,
            buf,
            (DWORD)len,
            NULL);
      if (n > 3) {
        /* Drop final '.', CR, LF */
        if (buf[n - 1] == '\n') n--;
        if (buf[n - 1] == '\r') n--;
        if (buf[n - 1] == '.') n--;
        buf[n] = '\0';
      }
      return (int)n;
    }

    if (errno != 0)
    {
      /* C runtime error that has no corresponding DOS error code */
      const char *s = strerror(errno);
      size_t n = strlen(s);
      if (n >= len) n = len - 1;
      strncpy(buf, s, n);
      buf[n] = '\0';
      return (int)n;
    }
    return 0;
}