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

/*
 * Copyright (c) 1997, 2014, Oracle and/or its affiliates. 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 *
 */

// Must be at least Windows Vista or Server 2008 to use InitOnceExecuteOnce
#define _WIN32_WINNT 0x0600

// no precompiled headers
#include "classfile/classLoader.hpp"
#include "classfile/systemDictionary.hpp"
#include "classfile/vmSymbols.hpp"
#include "code/icBuffer.hpp"
#include "code/vtableStubs.hpp"
#include "compiler/compileBroker.hpp"
#include "compiler/disassembler.hpp"
#include "interpreter/interpreter.hpp"
#include "jvm_windows.h"
#include "memory/allocation.inline.hpp"
#include "memory/filemap.hpp"
#include "mutex_windows.inline.hpp"
#include "oops/oop.inline.hpp"
#include "os_share_windows.hpp"
#include "os_windows.inline.hpp"
#include "prims/jniFastGetField.hpp"
#include "prims/jvm.h"
#include "prims/jvm_misc.hpp"
#include "runtime/arguments.hpp"
#include "runtime/atomic.inline.hpp"
#include "runtime/extendedPC.hpp"
#include "runtime/globals.hpp"
#include "runtime/interfaceSupport.hpp"
#include "runtime/java.hpp"
#include "runtime/javaCalls.hpp"
#include "runtime/mutexLocker.hpp"
#include "runtime/objectMonitor.hpp"
#include "runtime/orderAccess.inline.hpp"
#include "runtime/osThread.hpp"
#include "runtime/perfMemory.hpp"
#include "runtime/sharedRuntime.hpp"
#include "runtime/statSampler.hpp"
#include "runtime/stubRoutines.hpp"
#include "runtime/thread.inline.hpp"
#include "runtime/threadCritical.hpp"
#include "runtime/timer.hpp"
#include "runtime/vm_version.hpp"
#include "services/attachListener.hpp"
#include "services/memTracker.hpp"
#include "services/runtimeService.hpp"
#include "utilities/decoder.hpp"
#include "utilities/defaultStream.hpp"
#include "utilities/events.hpp"
#include "utilities/growableArray.hpp"
#include "utilities/vmError.hpp"

#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 <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 _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;

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);
    }
    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;
}

bool os::unsetenv(const char* name) {
  assert(name != NULL, "Null pointer");
  return (SetEnvironmentVariable(name, NULL) == TRUE);
}

// 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;
}

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

LONG WINAPI Handle_FLT_Exception(struct _EXCEPTION_POINTERS* exceptionInfo);

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.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, mtInternal);
    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,
                                mtInternal);
    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 system wide Java Extensions directory (Java only)
    // 3. System directory (GetSystemDirectory)
    // 4. Windows directory (GetWindowsDirectory)
    // 5. The PATH environment variable
    // 6. The current directory

    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, mtInternal);

    library_path[0] = '\0';

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

    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);
    }

    strcat(library_path, ";.");

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

  // 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, mtInternal);
    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();
}

// RtlCaptureStackBackTrace Windows API may not exist prior to Windows XP.
// So far, this method is only used by Native Memory Tracking, which is
// only supported on Windows XP or later.
//
int os::get_native_stack(address* stack, int frames, int toSkip) {
#ifdef _NMT_NOINLINE_
  toSkip++;
#endif
  int captured = Kernel32Dll::RtlCaptureStackBackTrace(toSkip + 1, frames,
                                                       (PVOID*)stack, NULL);
  for (int index = captured; index < frames; index ++) {
    stack[index] = NULL;
  }
  return captured;
}


// 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
  //
  // This is the stack layout you get on NT/IA64 if you specify 1MB stack limit
  // at thread creation (1MB backing store growing upwards, 1MB memory stack
  // growing downwards, 2MB summed up)
  //
  // ...
  // ------- top of stack (high address) -----
  // |
  // |      1MB
  // |      Backing Store (Register Stack)
  // |
  // |         / \
  // |          |
  // |          |
  // |          |
  // ------------------------ stack base -----
  // |      1MB
  // |      Memory Stack
  // |
  // |          |
  // |          |
  // |          |
  // |         \ /
  // |
  // ----- bottom of stack (low address) -----
  // ...

  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;
}

struct tm* os::localtime_pd(const time_t* clock, struct tm* res) {
  const struct tm* time_struct_ptr = localtime(clock);
  if (time_struct_ptr != NULL) {
    *res = *time_struct_ptr;
    return res;
  }
  return NULL;
}

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);
    }
  }

  // Diagnostic code to investigate JDK-6573254
  int res = 90115;  // non-java thread
  if (thread->is_Java_thread()) {
    res = 60115;    // java thread
  }

  // Install a win32 structured exception handler around every thread created
  // by VM, so VM can generate 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);
  }

  // Thread must not return from exit_process_or_thread(), but if it does,
  // let it proceed to exit normally
  return (unsigned)os::win32::exit_process_or_thread(os::win32::EPT_THREAD, res);
}

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 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 (win32::_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 (win32::_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() {
  // Use GlobalMemoryStatusEx() because GlobalMemoryStatus() may return incorrect
  // value if total memory is larger than 4GB
  MEMORYSTATUSEX ms;
  ms.dwLength = sizeof(ms);
  GlobalMemoryStatusEx(&ms);

  return (julong)ms.ullAvailPhys;
}

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

bool os::has_allocatable_memory_limit(julong* limit) {
  MEMORYSTATUSEX ms;
  ms.dwLength = sizeof(ms);
  GlobalMemoryStatusEx(&ms);
#ifdef _LP64
  *limit = (julong)ms.ullAvailVirtual;
  return true;
#else
  // Limit to 1400m because of the 2gb address space wall
  *limit = MIN2((julong)1400*M, (julong)ms.ullAvailVirtual);
  return true;
#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;
  }
}

void os::set_native_thread_name(const char *name) {
  // Not yet implemented.
  return;
}

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;
}

void os::win32::initialize_performance_counter() {
  LARGE_INTEGER count;
  if (QueryPerformanceFrequency(&count)) {
    win32::_has_performance_count = 1;
    performance_frequency = as_long(count);
    QueryPerformanceCounter(&count);
    initial_performance_count = as_long(count);
  } else {
    win32::_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)) {
    fatal(err_msg("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;
}

bool os::supports_vtime() { return true; }
bool os::enable_vtime() { return false; }
bool os::vtime_enabled() { return false; }

double os::elapsedVTime() {
  FILETIME created;
  FILETIME exited;
  FILETIME kernel;
  FILETIME user;
  if (GetThreadTimes(GetCurrentThread(), &created, &exited, &kernel, &user) != 0) {
    // the resolution of windows_to_java_time() should be sufficient (ms)
    return (double) (windows_to_java_time(kernel) + windows_to_java_time(user)) / MILLIUNITS;
  } else {
    return elapsedTime();
  }
}

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

jlong os::javaTimeNanos() {
  if (!win32::_has_performance_count) {
    return javaTimeMillis() * NANOSECS_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) * NANOSECS_PER_SEC);
    return time;
  }
}

void os::javaTimeNanos_info(jvmtiTimerInfo *info_ptr) {
  if (!win32::_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 < NANOSECS_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 > NANOSECS_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 / NANOSECS_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();
  }
}


static BOOL (WINAPI *_MiniDumpWriteDump)(HANDLE, DWORD, HANDLE, MINIDUMP_TYPE,
                                         PMINIDUMP_EXCEPTION_INFORMATION,
                                         PMINIDUMP_USER_STREAM_INFORMATION,
                                         PMINIDUMP_CALLBACK_INFORMATION);

void os::check_or_create_dump(void* exceptionRecord, void* contextRecord, char* buffer, size_t bufferSize) {
  HINSTANCE dbghelp;
  EXCEPTION_POINTERS ep;
  MINIDUMP_EXCEPTION_INFORMATION mei;
  MINIDUMP_EXCEPTION_INFORMATION* pmei;

  HANDLE hProcess = GetCurrentProcess();
  DWORD processId = GetCurrentProcessId();
  HANDLE dumpFile;
  MINIDUMP_TYPE dumpType;
  static const char* cwd;

// Default is to always create dump for debug builds, on product builds only dump on server versions of Windows.
#ifndef ASSERT
  // If running on a client version of Windows and user has not explicitly enabled dumping
  if (!os::win32::is_windows_server() && !CreateMinidumpOnCrash) {
    VMError::report_coredump_status("Minidumps are not enabled by default on client versions of Windows", false);
    return;
    // If running on a server version of Windows and user has explictly disabled dumping
  } else if (os::win32::is_windows_server() && !FLAG_IS_DEFAULT(CreateMinidumpOnCrash) && !CreateMinidumpOnCrash) {
    VMError::report_coredump_status("Minidump has been disabled from the command line", false);
    return;
  }
#else
  if (!FLAG_IS_DEFAULT(CreateMinidumpOnCrash) && !CreateMinidumpOnCrash) {
    VMError::report_coredump_status("Minidump has been disabled from the command line", false);
    return;
  }
#endif

  dbghelp = os::win32::load_Windows_dll("DBGHELP.DLL", NULL, 0);

  if (dbghelp == NULL) {
    VMError::report_coredump_status("Failed to load dbghelp.dll", false);
    return;
  }

  _MiniDumpWriteDump =
      CAST_TO_FN_PTR(BOOL(WINAPI *)(HANDLE, DWORD, HANDLE, MINIDUMP_TYPE,
                                    PMINIDUMP_EXCEPTION_INFORMATION,
                                    PMINIDUMP_USER_STREAM_INFORMATION,
                                    PMINIDUMP_CALLBACK_INFORMATION),
                                    GetProcAddress(dbghelp,
                                    "MiniDumpWriteDump"));

  if (_MiniDumpWriteDump == NULL) {
    VMError::report_coredump_status("Failed to find MiniDumpWriteDump() in module dbghelp.dll", false);
    return;
  }

  dumpType = (MINIDUMP_TYPE)(MiniDumpWithFullMemory | MiniDumpWithHandleData);

// Older versions of dbghelp.h doesn't contain all the dumptypes we want, dbghelp.h with
// API_VERSION_NUMBER 11 or higher contains the ones we want though
#if API_VERSION_NUMBER >= 11
  dumpType = (MINIDUMP_TYPE)(dumpType | MiniDumpWithFullMemoryInfo | MiniDumpWithThreadInfo |
                             MiniDumpWithUnloadedModules);
#endif

  cwd = get_current_directory(NULL, 0);
  jio_snprintf(buffer, bufferSize, "%s\\hs_err_pid%u.mdmp", cwd, current_process_id());
  dumpFile = CreateFile(buffer, GENERIC_WRITE, 0, NULL, CREATE_ALWAYS, FILE_ATTRIBUTE_NORMAL, NULL);

  if (dumpFile == INVALID_HANDLE_VALUE) {
    VMError::report_coredump_status("Failed to create file for dumping", false);
    return;
  }
  if (exceptionRecord != NULL && contextRecord != NULL) {
    ep.ContextRecord = (PCONTEXT) contextRecord;
    ep.ExceptionRecord = (PEXCEPTION_RECORD) exceptionRecord;

    mei.ThreadId = GetCurrentThreadId();
    mei.ExceptionPointers = &ep;
    pmei = &mei;
  } else {
    pmei = NULL;
  }


  // Older versions of dbghelp.dll (the one shipped with Win2003 for example) may not support all
  // the dump types we really want. If first call fails, lets fall back to just use MiniDumpWithFullMemory then.
  if (_MiniDumpWriteDump(hProcess, processId, dumpFile, dumpType, pmei, NULL, NULL) == false &&
      _MiniDumpWriteDump(hProcess, processId, dumpFile, (MINIDUMP_TYPE)MiniDumpWithFullMemory, pmei, NULL, NULL) == false) {
    DWORD error = GetLastError();
    LPTSTR msgbuf = NULL;

    if (FormatMessage(FORMAT_MESSAGE_ALLOCATE_BUFFER |
                      FORMAT_MESSAGE_FROM_SYSTEM |
                      FORMAT_MESSAGE_IGNORE_INSERTS,
                      NULL, error, 0, (LPTSTR)&msgbuf, 0, NULL) != 0) {

      jio_snprintf(buffer, bufferSize, "Call to MiniDumpWriteDump() failed (Error 0x%x: %s)", error, msgbuf);
      LocalFree(msgbuf);
    } else {
      // Call to FormatMessage failed, just include the result from GetLastError
      jio_snprintf(buffer, bufferSize, "Call to MiniDumpWriteDump() failed (Error 0x%x)", error);
    }
    VMError::report_coredump_status(buffer, false);
  } else {
    VMError::report_coredump_status(buffer, true);
  }

  CloseHandle(dumpFile);
}


void os::abort(bool dump_core) {
  os::shutdown();
  // no core dump on Windows
  win32::exit_process_or_thread(win32::EPT_PROCESS, 1);
}

// Die immediately, no exit hook, no abort hook, no cleanup.
void os::die() {
  win32::exit_process_or_thread(win32::EPT_PROCESS_DIE, -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), mtInternal);
  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, mtInternal);
  if (dirp->path == 0) {
    free(dirp, mtInternal);
    errno = ENOMEM;
    return 0;
  }
  strcpy(dirp->path, dirname);

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

// This must be hard coded because it's the system's temporary
// directory not the java application's temp directory, ala java.io.tmpdir.
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;
  }
}

static bool file_exists(const char* filename) {
  if (filename == NULL || strlen(filename) == 0) {
    return false;
  }
  return GetFileAttributes(filename) != INVALID_FILE_ATTRIBUTES;
}

bool os::dll_build_name(char *buffer, size_t buflen,
                        const char* pname, const char* fname) {
  bool retval = false;
  const size_t pnamelen = pname ? strlen(pname) : 0;
  const char c = (pnamelen > 0) ? pname[pnamelen-1] : 0;

  // Return error on buffer overflow.
  if (pnamelen + strlen(fname) + 10 > buflen) {
    return retval;
  }

  if (pnamelen == 0) {
    jio_snprintf(buffer, buflen, "%s.dll", fname);
    retval = true;
  } else if (c == ':' || c == '\\') {
    jio_snprintf(buffer, buflen, "%s%s.dll", pname, fname);
    retval = true;
  } else if (strchr(pname, *os::path_separator()) != NULL) {
    int n;
    char** pelements = split_path(pname, &n);
    if (pelements == NULL) {
      return false;
    }
    for (int i = 0; i < n; i++) {
      char* path = pelements[i];
      // Really shouldn't be NULL, but check can't hurt
      size_t plen = (path == NULL) ? 0 : strlen(path);
      if (plen == 0) {
        continue; // skip the empty path values
      }
      const char lastchar = path[plen - 1];
      if (lastchar == ':' || lastchar == '\\') {
        jio_snprintf(buffer, buflen, "%s%s.dll", path, fname);
      } else {
        jio_snprintf(buffer, buflen, "%s\\%s.dll", path, fname);
      }
      if (file_exists(buffer)) {
        retval = true;
        break;
      }
    }
    // release the storage
    for (int i = 0; i < n; i++) {
      if (pelements[i] != NULL) {
        FREE_C_HEAP_ARRAY(char, pelements[i], mtInternal);
      }
    }
    if (pelements != NULL) {
      FREE_C_HEAP_ARRAY(char*, pelements, mtInternal);
    }
  } else {
    jio_snprintf(buffer, buflen, "%s\\%s.dll", pname, fname);
    retval = true;
  }
  return retval;
}

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

//-----------------------------------------------------------
// Helper functions for fatal error handler
#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 (!os::PSApiDll::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

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(const char * mod_fname, address base_addr,
                                  address top_address, void * param) {
  struct _modinfo *pmod = (struct _modinfo *)param;
  if (!pmod) return -1;

  if (base_addr   <= pmod->addr &&
      top_address > 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) {
  // buf is not optional, but offset is optional
  assert(buf != NULL, "sanity check");

// 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;
  if (get_loaded_modules_info(_locate_module_by_addr, (void *)&mi)) {
    // buf already contains path name
    if (offset) *offset = addr - mi.base_addr;
    return true;
  }

  buf[0] = '\0';
  if (offset) *offset = -1;
  return false;
}

bool os::dll_address_to_function_name(address addr, char *buf,
                                      int buflen, int *offset) {
  // buf is not optional, but offset is optional
  assert(buf != NULL, "sanity check");

  if (Decoder::decode(addr, buf, buflen, offset)) {
    return true;
  }
  if (offset != NULL)  *offset  = -1;
  buf[0] = '\0';
  return false;
}

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

  if (base_addr   <= (address)_locate_jvm_dll &&
      top_address > (address)_locate_jvm_dll) {
    ((address*)param)[0] = base_addr;
    ((address*)param)[1] = top_address;
    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]) {
    if (!get_loaded_modules_info(_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(const char* fname, address base_address,
                         address top_address, void* param) {
  if (!param) return -1;

  outputStream* st = (outputStream*)param;

  st->print(PTR_FORMAT " - " PTR_FORMAT " \t%s\n", base_address, top_address, 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;
  }

  DWORD 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 os::lasterror 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)
  lasterror(ebuf, (size_t) ebuflen);
  ebuf[ebuflen - 1] = '\0';
  int fd = ::open(name, O_RDONLY | O_BINARY, 0);
  if (fd < 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(fd, IMAGE_FILE_PTR_TO_SIGNATURE) < 0)
     ||
     // Read location of signature
     (sizeof(signature_offset) !=
     (os::read(fd, (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(fd,
     signature_offset + IMAGE_FILE_SIGNATURE_LENGTH) < 0)
     ||
     // Read field that contains code of architecture
     // that dll was built for
     (sizeof(lib_arch) != (os::read(fd, (void*)&lib_arch, sizeof(lib_arch))))
    );

  ::close(fd);
  if (failed_to_get_lib_arch) {
    // file i/o error - report os::lasterror(...) 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 running architecture code in arch_array");

  // If the architecture is right
  // but some other error took place - report os::lasterror(...) 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) {
  st->print_cr("Dynamic libraries:");
  get_loaded_modules_info(_print_module, (void *)st);
}

int os::get_loaded_modules_info(os::LoadedModulesCallbackFunc callback, void *param) {
  HANDLE   hProcess;

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

  if (!os::PSApiDll::PSApiAvailable()) {
    return 0;
  }

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

  DWORD size_needed;
  if (!os::PSApiDll::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 (!os::PSApiDll::GetModuleFileNameEx(hProcess, modules[i],
                                           filename, sizeof(filename))) {
      filename[0] = '\0';
    }

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

    // Invoke callback function
    result = callback(filename, (address)modinfo.lpBaseOfDll,
                      (address)((u8)modinfo.lpBaseOfDll + (u8)modinfo.SizeOfImage), param);
    if (result) break;
  }

  CloseHandle(hProcess);
  return result;
}

void os::print_os_info_brief(outputStream* st) {
  os::print_os_info(st);
}

void os::print_os_info(outputStream* st) {
#ifdef ASSERT
  char buffer[1024];
  DWORD size = sizeof(buffer);
  st->print(" HostName: ");
  if (GetComputerNameEx(ComputerNameDnsHostname, buffer, &size)) {
    st->print("%s", buffer);
  } else {
    st->print("N/A");
  }
#endif
  st->print(" OS:");
  os::win32::print_windows_version(st);
}

void os::win32::print_windows_version(outputStream* st) {
  OSVERSIONINFOEX osvi;
  SYSTEM_INFO si;

  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;

  ZeroMemory(&si, sizeof(SYSTEM_INFO));
  if (os_vers >= 5002) {
    // Retrieve SYSTEM_INFO from GetNativeSystemInfo call so that we could
    // find out whether we are running on 64 bit processor or not.
    if (os::Kernel32Dll::GetNativeSystemInfoAvailable()) {
      os::Kernel32Dll::GetNativeSystemInfo(&si);
    } else {
      GetSystemInfo(&si);
    }
  }

  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:
      if (osvi.wProductType == VER_NT_WORKSTATION &&
          si.wProcessorArchitecture == PROCESSOR_ARCHITECTURE_AMD64) {
        st->print(" Windows XP x64 Edition");
      } else {
        st->print(" Windows Server 2003 family");
      }
      break;

    case 6000:
      if (osvi.wProductType == VER_NT_WORKSTATION) {
        st->print(" Windows Vista");
      } else {
        st->print(" Windows Server 2008");
      }
      break;

    case 6001:
      if (osvi.wProductType == VER_NT_WORKSTATION) {
        st->print(" Windows 7");
      } else {
        st->print(" Windows Server 2008 R2");
      }
      break;

    case 6002:
      if (osvi.wProductType == VER_NT_WORKSTATION) {
        st->print(" Windows 8");
      } else {
        st->print(" Windows Server 2012");
      }
      break;

    case 6003:
      if (osvi.wProductType == VER_NT_WORKSTATION) {
        st->print(" Windows 8.1");
      } else {
        st->print(" Windows Server 2012 R2");
      }
      break;

    default: // future os
      // Unrecognized 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);
    }
  }

  if (os_vers >= 6000 && si.wProcessorArchitecture == PROCESSOR_ARCHITECTURE_AMD64) {
    st->print(" , 64 bit");
  }

  st->print(" Build %d", osvi.dwBuildNumber);
  st->print(" %s", osvi.szCSDVersion);           // service pack
  st->cr();
}

void os::pd_print_cpu_info(outputStream* st) {
  // Nothing to do for now.
}

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

  // Use GlobalMemoryStatusEx() because GlobalMemoryStatus() may return incorrect
  // value if total memory is larger than 4GB
  MEMORYSTATUSEX ms;
  ms.dwLength = sizeof(ms);
  GlobalMemoryStatusEx(&ms);

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

  st->print(", swap %uk", ms.ullTotalPageFile >> 10);
  st->print("(%uk free)", ms.ullAvailPageFile >> 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
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;
  }

  buf[0] = '\0';
  if (Arguments::sun_java_launcher_is_altjvm()) {
    // Support for the java launcher's '-XXaltjvm=<path>' option. Check
    // for a JAVA_HOME environment variable and fix up the path so it
    // looks like jvm.dll is installed there (append a fake suffix
    // hotspot/jvm.dll).
    char* java_home_var = ::getenv("JAVA_HOME");
    if (java_home_var != NULL && java_home_var[0] != 0 &&
        strlen(java_home_var) < (size_t)buflen) {
      strncpy(buf, java_home_var, buflen);

      // determine if this is a legacy image or modules image
      // modules image doesn't have "jre" subdirectory
      size_t len = strlen(buf);
      char* jrebin_p = buf + len;
      jio_snprintf(jrebin_p, buflen-len, "\\jre\\bin\\");
      if (0 != _access(buf, 0)) {
        jio_snprintf(jrebin_p, buflen-len, "\\bin\\");
      }
      len = strlen(buf);
      jio_snprintf(buf + len, buflen-len, "hotspot\\jvm.dll");
    }
  }

  if (buf[0] == '\0') {
    GetModuleFileName(vm_lib_handle, buf, buflen);
  }
  strncpy(saved_jvm_path, buf, MAX_PATH);
}


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
}

// This method is a copy of JDK's sysGetLastErrorString
// from src/windows/hpi/src/system_md.c

size_t os::lasterror(char* buf, size_t len) {
  DWORD 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 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 n;
  }

  return 0;
}

int os::get_last_error() {
  DWORD error = GetLastError();
  if (error == 0) {
    error = errno;
  }
  return (int)error;
}

// 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_LOGOFF_EVENT: {
    // Don't terminate JVM if it is running in a non-interactive session,
    // such as a service process.
    USEROBJECTFLAGS flags;
    HANDLE handle = GetProcessWindowStation();
    if (handle != NULL &&
        GetUserObjectInformation(handle, UOI_FLAGS, &flags,
        sizeof(USEROBJECTFLAGS), NULL)) {
      // If it is a non-interactive session, let next handler to deal
      // with it.
      if ((flags.dwFlags & WSF_VISIBLE) == 0) {
        return FALSE;
      }
    }
  }
  case CTRL_CLOSE_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 = NULL;

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;
  if (sig_sem != NULL) {
    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
  // Do not blow up if no thread info available.
  if (thread) {
    // Saving PRECISE pc (with slot information) in thread.
    uint64_t precise_pc = (uint64_t) exceptionInfo->ExceptionRecord->ExceptionAddress;
    // Convert precise PC into "Unix" format
    precise_pc = (precise_pc & 0xFFFFFFFFFFFFFFF0) | ((precise_pc & 0xF) >> 2);
    thread->set_saved_exception_pc((address)precise_pc);
  }
  // Set pc to handler
  exceptionInfo->ContextRecord->StIIP = (DWORD64)handler;
  // Clear out psr.ri (= Restart Instruction) in order to continue
  // at the beginning of the target bundle.
  exceptionInfo->ContextRecord->StIPSR &= 0xFFFFF9FFFFFFFFFF;
  assert(((DWORD64)handler & 0xF) == 0, "Target address must point to the beginning of a bundle!");
#elif _M_AMD64
  // Do not blow up if no thread info available.
  if (thread) {
    thread->set_saved_exception_pc((address)(DWORD_PTR)exceptionInfo->ContextRecord->Rip);
  }
  // Set pc to handler
  exceptionInfo->ContextRecord->Rip = (DWORD64)handler;
#else
  // Do not blow up if no thread info available.
  if (thread) {
    thread->set_saved_exception_pc((address)(DWORD_PTR)exceptionInfo->ContextRecord->Eip);
  }
  // Set pc to handler
  exceptionInfo->ContextRecord->Eip = (DWORD)(DWORD_PTR)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

// Handle NAT Bit consumption on IA64.
#ifdef _M_IA64
  #define EXCEPTION_REG_NAT_CONSUMPTION    STATUS_REG_NAT_CONSUMPTION
#endif

// Windows Vista/2008 heap corruption check
#define EXCEPTION_HEAP_CORRUPTION        0xC0000374

#define def_excpt(val) #val, val

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

// All Visual C++ exceptions thrown from code generated by the Microsoft Visual
// C++ compiler contain this error code. Because this is a compiler-generated
// error, the code is not listed in the Win32 API header files.
// The code is actually a cryptic mnemonic device, with the initial "E"
// standing for "exception" and the final 3 bytes (0x6D7363) representing the
// ASCII values of "msc".

#define EXCEPTION_UNCAUGHT_CXX_EXCEPTION    0xE06D7363


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),
    def_excpt(EXCEPTION_UNCAUGHT_CXX_EXCEPTION),
    def_excpt(EXCEPTION_HEAP_CORRUPTION),
#ifdef _M_IA64
    def_excpt(EXCEPTION_REG_NAT_CONSUMPTION),
#endif
    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;
  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;
  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;
}

//-----------------------------------------------------------------------------
LONG WINAPI Handle_FLT_Exception(struct _EXCEPTION_POINTERS* exceptionInfo) {
  PCONTEXT ctx = exceptionInfo->ContextRecord;
#ifndef  _WIN64
  // handle exception caused by native method modifying control word
  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);
  }
#else // !_WIN64
  // On Windows, the mxcsr control bits are non-volatile across calls
  // See also CR 6192333
  //
  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

  return EXCEPTION_CONTINUE_SEARCH;
}

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
  // On Itanium, we need the "precise pc", which has the slot number coded
  // into the least 4 bits: 0000=slot0, 0100=slot1, 1000=slot2 (Windows format).
  address pc = (address) exceptionInfo->ExceptionRecord->ExceptionAddress;
  // Convert the pc to "Unix format", which has the slot number coded
  // into the least 2 bits: 0000=slot0, 0001=slot1, 0010=slot2
  // This is needed for IA64 because "relocation" / "implicit null check" / "poll instruction"
  // information is saved in the Unix format.
  address pc_unix_format = (address) ((((uint64_t)pc) & 0xFFFFFFFFFFFFFFF0) | ((((uint64_t)pc) & 0xF) >> 2));
#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

  // Handle SafeFetch32 and SafeFetchN exceptions.
  if (StubRoutines::is_safefetch_fault(pc)) {
    return Handle_Exception(exceptionInfo, StubRoutines::continuation_for_safefetch_fault(pc));
  }

#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 ((exception_code == EXCEPTION_ACCESS_VIOLATION) &&
      VM_Version::is_cpuinfo_segv_addr(pc)) {
    // Verify that OS save/restore AVX registers.
    return Handle_Exception(exceptionInfo, VM_Version::cpuinfo_cont_addr());
  }

  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
        // Use guard page for register stack.
        PEXCEPTION_RECORD exceptionRecord = exceptionInfo->ExceptionRecord;
        address addr = (address) exceptionRecord->ExceptionInformation[1];
        // Check for a register stack overflow on Itanium
        if (thread->addr_inside_register_stack_red_zone(addr)) {
          // Fatal red zone violation happens if the Java program
          // catches a StackOverflow error and does so much processing
          // that it runs beyond the unprotected yellow guard zone. As
          // a result, we are out of here.
          fatal("ERROR: Unrecoverable stack overflow happened. JVM will exit.");
        } else if(thread->addr_inside_register_stack(addr)) {
          // 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();
          // Tracing with +Verbose.
          if (Verbose) {
            tty->print_cr("SOF Compiled Register Stack overflow at " INTPTR_FORMAT " (SIGSEGV)", pc);
            tty->print_cr("Register Stack access at " INTPTR_FORMAT, addr);
            tty->print_cr("Register Stack base " INTPTR_FORMAT, thread->register_stack_base());
            tty->print_cr("Register Stack [" INTPTR_FORMAT "," INTPTR_FORMAT "]",
                          thread->register_stack_base(),
                          thread->register_stack_base() + thread->stack_size());
          }

          // Reguard the permanent register stack red zone just to be sure.
          // We saw Windows silently disabling this without telling us.
          thread->enable_register_stack_red_zone();

          return Handle_Exception(exceptionInfo,
                                  SharedRuntime::continuation_for_implicit_exception(thread, pc, SharedRuntime::STACK_OVERFLOW));
        }
#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,
                              !ExecMem);
            return EXCEPTION_CONTINUE_EXECUTION;
          } else
#endif
          {
            // Null pointer exception.
#ifdef _M_IA64
            // Process implicit null checks in compiled code. Note: Implicit null checks
            // can happen even if "ImplicitNullChecks" is disabled, e.g. in vtable stubs.
            if (CodeCache::contains((void*) pc_unix_format) && !MacroAssembler::needs_explicit_null_check((intptr_t) addr)) {
              CodeBlob *cb = CodeCache::find_blob_unsafe(pc_unix_format);
              // Handle implicit null check in UEP method entry
              if (cb && (cb->is_frame_complete_at(pc) ||
                         (cb->is_nmethod() && ((nmethod *)cb)->inlinecache_check_contains(pc)))) {
                if (Verbose) {
                  intptr_t *bundle_start = (intptr_t*) ((intptr_t) pc_unix_format & 0xFFFFFFFFFFFFFFF0);
                  tty->print_cr("trap: null_check at " INTPTR_FORMAT " (SIGSEGV)", pc_unix_format);
                  tty->print_cr("      to addr " INTPTR_FORMAT, addr);
                  tty->print_cr("      bundle is " INTPTR_FORMAT " (high), " INTPTR_FORMAT " (low)",
                                *(bundle_start + 1), *bundle_start);
                }
                return Handle_Exception(exceptionInfo,
                                        SharedRuntime::continuation_for_implicit_exception(thread, pc_unix_format, SharedRuntime::IMPLICIT_NULL));
              }
            }

            // Implicit null checks were processed above.  Hence, we should not reach
            // here in the usual case => die!
            if (Verbose) 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

      // Stack overflow or null pointer exception in native code.
      report_error(t, exception_code, pc, exceptionInfo->ExceptionRecord,
                   exceptionInfo->ContextRecord);
      return EXCEPTION_CONTINUE_SEARCH;
    } // /EXCEPTION_ACCESS_VIOLATION
    // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
#if defined _M_IA64
    else if ((exception_code == EXCEPTION_ILLEGAL_INSTRUCTION ||
              exception_code == EXCEPTION_ILLEGAL_INSTRUCTION_2)) {
      M37 handle_wrong_method_break(0, NativeJump::HANDLE_WRONG_METHOD, PR0);

      // Compiled method patched to be non entrant? Following conditions must apply:
      // 1. must be first instruction in bundle
      // 2. must be a break instruction with appropriate code
      if ((((uint64_t) pc & 0x0F) == 0) &&
          (((IPF_Bundle*) pc)->get_slot0() == handle_wrong_method_break.bits())) {
        return Handle_Exception(exceptionInfo,
                                (address)SharedRuntime::get_handle_wrong_method_stub());
      }
    } // /EXCEPTION_ILLEGAL_INSTRUCTION
#endif


    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
    }
    if (((thread->thread_state() == _thread_in_Java) ||
         (thread->thread_state() == _thread_in_native)) &&
         exception_code != EXCEPTION_UNCAUGHT_CXX_EXCEPTION) {
      LONG result=Handle_FLT_Exception(exceptionInfo);
      if (result==EXCEPTION_CONTINUE_EXECUTION) return result;
    }
  }

  if (exception_code != EXCEPTION_BREAKPOINT) {
    report_error(t, exception_code, pc, exceptionInfo->ExceptionRecord,
                 exceptionInfo->ContextRecord);
  }
  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

void os::win32::call_test_func_with_wrapper(void (*funcPtr)(void)) {
  // Install a win32 structured exception handler around the test
  // function call so the VM can generate an error dump if needed.
  __try {
    (*funcPtr)();
  } __except(topLevelExceptionFilter(
                                     (_EXCEPTION_POINTERS*)_exception_info())) {
    // Nothing to do.
  }
}

// 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

static HANDLE    _hProcess;
static HANDLE    _hToken;

// Container for NUMA node list info
class NUMANodeListHolder {
 private:
  int *_numa_used_node_list;  // allocated below
  int _numa_used_node_count;

  void free_node_list() {
    if (_numa_used_node_list != NULL) {
      FREE_C_HEAP_ARRAY(int, _numa_used_node_list, mtInternal);
    }
  }

 public:
  NUMANodeListHolder() {
    _numa_used_node_count = 0;
    _numa_used_node_list = NULL;
    // do rest of initialization in build routine (after function pointers are set up)
  }

  ~NUMANodeListHolder() {
    free_node_list();
  }

  bool build() {
    DWORD_PTR proc_aff_mask;
    DWORD_PTR sys_aff_mask;
    if (!GetProcessAffinityMask(GetCurrentProcess(), &proc_aff_mask, &sys_aff_mask)) return false;
    ULONG highest_node_number;
    if (!os::Kernel32Dll::GetNumaHighestNodeNumber(&highest_node_number)) return false;
    free_node_list();
    _numa_used_node_list = NEW_C_HEAP_ARRAY(int, highest_node_number + 1, mtInternal);
    for (unsigned int i = 0; i <= highest_node_number; i++) {
      ULONGLONG proc_mask_numa_node;
      if (!os::Kernel32Dll::GetNumaNodeProcessorMask(i, &proc_mask_numa_node)) return false;
      if ((proc_aff_mask & proc_mask_numa_node)!=0) {
        _numa_used_node_list[_numa_used_node_count++] = i;
      }
    }
    return (_numa_used_node_count > 1);
  }

  int get_count() { return _numa_used_node_count; }
  int get_node_list_entry(int n) {
    // for indexes out of range, returns -1
    return (n < _numa_used_node_count ? _numa_used_node_list[n] : -1);
  }

} numa_node_list_holder;



static size_t _large_page_size = 0;

static bool resolve_functions_for_large_page_init() {
  return os::Kernel32Dll::GetLargePageMinimumAvailable() &&
    os::Advapi32Dll::AdvapiAvailable();
}

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

  LUID luid;
  if (_hProcess != NULL &&
      os::Advapi32Dll::OpenProcessToken(_hProcess, TOKEN_ADJUST_PRIVILEGES, &_hToken) &&
      os::Advapi32Dll::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 (os::Advapi32Dll::AdjustTokenPrivileges(_hToken, false, &tp, sizeof(tp), NULL, NULL) &&
        (GetLastError() == ERROR_SUCCESS)) {
      return true;
    }
  }

  return false;
}

static void cleanup_after_large_page_init() {
  if (_hProcess) CloseHandle(_hProcess);
  _hProcess = NULL;
  if (_hToken) CloseHandle(_hToken);
  _hToken = NULL;
}

static bool numa_interleaving_init() {
  bool success = false;
  bool use_numa_interleaving_specified = !FLAG_IS_DEFAULT(UseNUMAInterleaving);

  // print a warning if UseNUMAInterleaving flag is specified on command line
  bool warn_on_failure = use_numa_interleaving_specified;
#define WARN(msg) if (warn_on_failure) { warning(msg); }

  // NUMAInterleaveGranularity cannot be less than vm_allocation_granularity (or _large_page_size if using large pages)
  size_t min_interleave_granularity = UseLargePages ? _large_page_size : os::vm_allocation_granularity();
  NUMAInterleaveGranularity = align_size_up(NUMAInterleaveGranularity, min_interleave_granularity);

  if (os::Kernel32Dll::NumaCallsAvailable()) {
    if (numa_node_list_holder.build()) {
      if (PrintMiscellaneous && Verbose) {
        tty->print("NUMA UsedNodeCount=%d, namely ", numa_node_list_holder.get_count());
        for (int i = 0; i < numa_node_list_holder.get_count(); i++) {
          tty->print("%d ", numa_node_list_holder.get_node_list_entry(i));
        }
        tty->print("\n");
      }
      success = true;
    } else {
      WARN("Process does not cover multiple NUMA nodes.");
    }
  } else {
    WARN("NUMA Interleaving is not supported by the operating system.");
  }
  if (!success) {
    if (use_numa_interleaving_specified) WARN("...Ignoring UseNUMAInterleaving flag.");
  }
  return success;
#undef WARN
}

// this routine is used whenever we need to reserve a contiguous VA range
// but we need to make separate VirtualAlloc calls for each piece of the range
// Reasons for doing this:
//  * UseLargePagesIndividualAllocation was set (normally only needed on WS2003 but possible to be set otherwise)
//  * UseNUMAInterleaving requires a separate node for each piece
static char* allocate_pages_individually(size_t bytes, char* addr, DWORD flags,
                                         DWORD prot,
                                         bool should_inject_error = false) {
  char * p_buf;
  // note: at setup time we guaranteed that NUMAInterleaveGranularity was aligned up to a page size
  size_t page_size = UseLargePages ? _large_page_size : os::vm_allocation_granularity();
  size_t chunk_size = UseNUMAInterleaving ? NUMAInterleaveGranularity : page_size;

  // 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 + chunk_size;
  if (bytes > size_of_reserve) {
    // Overflowed.
    return NULL;
  }
  p_buf = (char *) VirtualAlloc(addr,
                                size_of_reserve,  // size of Reserve
                                MEM_RESERVE,
                                PAGE_READWRITE);
  // If reservation failed, return NULL
  if (p_buf == NULL) return NULL;
  MemTracker::record_virtual_memory_reserve((address)p_buf, size_of_reserve, CALLER_PC);
  os::release_memory(p_buf, bytes + chunk_size);

  // we still need to round up to a page boundary (in case we are using large pages)
  // but not to a chunk boundary (in case InterleavingGranularity doesn't align with page size)
  // instead we handle this in the bytes_to_rq computation below
  p_buf = (char *) align_size_up((size_t)p_buf, page_size);

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

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

  int count=0;
  while (bytes_remaining) {
    // select bytes_to_rq to get to the next chunk_size boundary

    size_t bytes_to_rq = MIN2(bytes_remaining, chunk_size - ((size_t)next_alloc_addr % chunk_size));
    // Note allocate and commit
    char * p_new;

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

    if (inject_error_now) {
      p_new = NULL;
    } else {
      if (!UseNUMAInterleaving) {
        p_new = (char *) VirtualAlloc(next_alloc_addr,
                                      bytes_to_rq,
                                      flags,
                                      prot);
      } else {
        // get the next node to use from the used_node_list
        assert(numa_node_list_holder.get_count() > 0, "Multiple NUMA nodes expected");
        DWORD node = numa_node_list_holder.get_node_list_entry(count % numa_node_list_holder.get_count());
        p_new = (char *)os::Kernel32Dll::VirtualAllocExNuma(hProc,
                                                            next_alloc_addr,
                                                            bytes_to_rq,
                                                            flags,
                                                            prot,
                                                            node);
      }
    }

    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;
        // NMT has yet to record any individual blocks, so it
        // need to create a dummy 'reserve' record to match
        // the release.
        MemTracker::record_virtual_memory_reserve((address)p_buf,
                                                  bytes_to_release, CALLER_PC);
        os::release_memory(p_buf, bytes_to_release);
      }
#ifdef ASSERT
      if (should_inject_error) {
        if (TracePageSizes && Verbose) {
          tty->print_cr("Reserving pages individually failed.");
        }
      }
#endif
      return NULL;
    }

    bytes_remaining -= bytes_to_rq;
    next_alloc_addr += bytes_to_rq;
    count++;
  }
  // Although the memory is allocated individually, it is returned as one.
  // NMT records it as one block.
  if ((flags & MEM_COMMIT) != 0) {
    MemTracker::record_virtual_memory_reserve_and_commit((address)p_buf, bytes, CALLER_PC);
  } else {
    MemTracker::record_virtual_memory_reserve((address)p_buf, bytes, CALLER_PC);
  }

  // made it this far, success
  return p_buf;
}



void os::large_page_init() {
  if (!UseLargePages) return;

  // 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 = os::Kernel32Dll::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();
  UseLargePages = 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::pd_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);
    }
  }
}

// Multiple threads can race in this code but it's not possible to unmap small sections of
// virtual space to get requested alignment, like posix-like os's.
// Windows prevents multiple thread from remapping over each other so this loop is thread-safe.
char* os::reserve_memory_aligned(size_t size, size_t alignment) {
  assert((alignment & (os::vm_allocation_granularity() - 1)) == 0,
         "Alignment must be a multiple of allocation granularity (page size)");
  assert((size & (alignment -1)) == 0, "size must be 'alignment' aligned");

  size_t extra_size = size + alignment;
  assert(extra_size >= size, "overflow, size is too large to allow alignment");

  char* aligned_base = NULL;

  do {
    char* extra_base = os::reserve_memory(extra_size, NULL, alignment);
    if (extra_base == NULL) {
      return NULL;
    }
    // Do manual alignment
    aligned_base = (char*) align_size_up((uintptr_t) extra_base, alignment);

    os::release_memory(extra_base, extra_size);

    aligned_base = os::reserve_memory(size, aligned_base);

  } while (aligned_base == NULL);

  return aligned_base;
}

char* os::pd_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;
  // note that if UseLargePages is on, all the areas that require interleaving
  // will go thru reserve_memory_special rather than thru here.
  bool use_individual = (UseNUMAInterleaving && !UseLargePages);
  if (!use_individual) {
    res = (char*)VirtualAlloc(addr, bytes, MEM_RESERVE, PAGE_READWRITE);
  } else {
    elapsedTimer reserveTimer;
    if (Verbose && PrintMiscellaneous) reserveTimer.start();
    // in numa interleaving, we have to allocate pages individually
    // (well really chunks of NUMAInterleaveGranularity size)
    res = allocate_pages_individually(bytes, addr, MEM_RESERVE, PAGE_READWRITE);
    if (res == NULL) {
      warning("NUMA page allocation failed");
    }
    if (Verbose && PrintMiscellaneous) {
      reserveTimer.stop();
      tty->print_cr("reserve_memory of %Ix bytes took " JLONG_FORMAT " ms (" JLONG_FORMAT " ticks)", bytes,
                    reserveTimer.milliseconds(), reserveTimer.ticks());
    }
  }
  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::pd_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, size_t alignment, char* addr,
                                 bool exec) {
  assert(UseLargePages, "only for large pages");

  if (!is_size_aligned(bytes, os::large_page_size()) || alignment > os::large_page_size()) {
    return NULL; // Fallback to small pages.
  }

  const DWORD prot = exec ? PAGE_EXECUTE_READWRITE : PAGE_READWRITE;
  const DWORD flags = MEM_RESERVE | MEM_COMMIT | MEM_LARGE_PAGES;

  // with large pages, there are two cases where we need to use Individual Allocation
  // 1) the UseLargePagesIndividualAllocation flag is set (set by default on WS2003)
  // 2) NUMA Interleaving is enabled, in which case we use a different node for each page
  if (UseLargePagesIndividualAllocation || UseNUMAInterleaving) {
    if (TracePageSizes && Verbose) {
      tty->print_cr("Reserving large pages individually.");
    }
    char * p_buf = allocate_pages_individually(bytes, addr, flags, prot, LargePagesIndividualAllocationInjectError);
    if (p_buf == NULL) {
      // give an appropriate warning message
      if (UseNUMAInterleaving) {
        warning("NUMA large page allocation failed, UseLargePages flag ignored");
      }
      if (UseLargePagesIndividualAllocation) {
        warning("Individually allocated large pages failed, "
                "use -XX:-UseLargePagesIndividualAllocation to turn off");
      }
      return NULL;
    }

    return p_buf;

  } else {
    if (TracePageSizes && Verbose) {
      tty->print_cr("Reserving large pages in a single large chunk.");
    }
    // normal policy just allocate it all at once
    DWORD flag = MEM_RESERVE | MEM_COMMIT | MEM_LARGE_PAGES;
    char * res = (char *)VirtualAlloc(addr, bytes, flag, prot);
    if (res != NULL) {
      MemTracker::record_virtual_memory_reserve_and_commit((address)res, bytes, CALLER_PC);
    }

    return res;
  }
}

bool os::release_memory_special(char* base, size_t bytes) {
  assert(base != NULL, "Sanity check");
  return release_memory(base, bytes);
}

void os::print_statistics() {
}

static void warn_fail_commit_memory(char* addr, size_t bytes, bool exec) {
  int err = os::get_last_error();
  char buf[256];
  size_t buf_len = os::lasterror(buf, sizeof(buf));
  warning("INFO: os::commit_memory(" PTR_FORMAT ", " SIZE_FORMAT
          ", %d) failed; error='%s' (DOS error/errno=%d)", addr, bytes,
          exec, buf_len != 0 ? buf : "<no_error_string>", err);
}

bool os::pd_commit_memory(char* addr, size_t bytes, bool exec) {
  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.

  // unless we have NUMAInterleaving enabled, the range of a commit
  // is always within a reserve covered by a single VirtualAlloc
  // in that case we can just do a single commit for the requested size
  if (!UseNUMAInterleaving) {
    if (VirtualAlloc(addr, bytes, MEM_COMMIT, PAGE_READWRITE) == NULL) {
      NOT_PRODUCT(warn_fail_commit_memory(addr, bytes, exec);)
      return false;
    }
    if (exec) {
      DWORD oldprot;
      // Windows doc says to use VirtualProtect to get execute permissions
      if (!VirtualProtect(addr, bytes, PAGE_EXECUTE_READWRITE, &oldprot)) {
        NOT_PRODUCT(warn_fail_commit_memory(addr, bytes, exec);)
        return false;
      }
    }
    return true;
  } else {

    // when NUMAInterleaving is enabled, the commit might cover a range that
    // came from multiple VirtualAlloc reserves (using allocate_pages_individually).
    // VirtualQuery can help us determine that.  The RegionSize that VirtualQuery
    // returns represents the number of bytes that can be committed in one step.
    size_t bytes_remaining = bytes;
    char * next_alloc_addr = addr;
    while (bytes_remaining > 0) {
      MEMORY_BASIC_INFORMATION alloc_info;
      VirtualQuery(next_alloc_addr, &alloc_info, sizeof(alloc_info));
      size_t bytes_to_rq = MIN2(bytes_remaining, (size_t)alloc_info.RegionSize);
      if (VirtualAlloc(next_alloc_addr, bytes_to_rq, MEM_COMMIT,
                       PAGE_READWRITE) == NULL) {
        NOT_PRODUCT(warn_fail_commit_memory(next_alloc_addr, bytes_to_rq,
                                            exec);)
        return false;
      }
      if (exec) {
        DWORD oldprot;
        if (!VirtualProtect(next_alloc_addr, bytes_to_rq,
                            PAGE_EXECUTE_READWRITE, &oldprot)) {
          NOT_PRODUCT(warn_fail_commit_memory(next_alloc_addr, bytes_to_rq,
                                              exec);)
          return false;
        }
      }
      bytes_remaining -= bytes_to_rq;
      next_alloc_addr += bytes_to_rq;
    }
  }
  // if we made it this far, return true
  return true;
}

bool os::pd_commit_memory(char* addr, size_t size, size_t alignment_hint,
                          bool exec) {
  // alignment_hint is ignored on this OS
  return pd_commit_memory(addr, size, exec);
}

void os::pd_commit_memory_or_exit(char* addr, size_t size, bool exec,
                                  const char* mesg) {
  assert(mesg != NULL, "mesg must be specified");
  if (!pd_commit_memory(addr, size, exec)) {
    warn_fail_commit_memory(addr, size, exec);
    vm_exit_out_of_memory(size, OOM_MMAP_ERROR, mesg);
  }
}

void os::pd_commit_memory_or_exit(char* addr, size_t size,
                                  size_t alignment_hint, bool exec,
                                  const char* mesg) {
  // alignment_hint is ignored on this OS
  pd_commit_memory_or_exit(addr, size, exec, mesg);
}

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

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

bool os::remove_stack_guard_pages(char* addr, size_t size) {
  return os::uncommit_memory(addr, size);
}

// 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_or_exit(addr, bytes, prot == MEM_PROT_RWX,
                          "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::pd_realign_memory(char *addr, size_t bytes, size_t alignment_hint) { }
void os::pd_free_memory(char *addr, size_t bytes, size_t alignment_hint) { }
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 MAX2(numa_node_list_holder.get_count(), 1); }
int os::numa_get_group_id()                            { return 0; }
size_t os::numa_get_leaf_groups(int *ids, size_t size) {
  if (numa_node_list_holder.get_count() == 0 && size > 0) {
    // Provide an answer for UMA systems
    ids[0] = 0;
    return 1;
  } else {
    // check for size bigger than actual groups_num
    size = MIN2(size, numa_get_groups_num());
    for (int i = 0; i < (int)size; i++) {
      ids[i] = numa_node_list_holder.get_node_list_entry(i);
    }
    return size;
  }
}

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
}

class HighResolutionInterval : public CHeapObj<mtThread> {
  // 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;
}

// Short sleep, direct OS call.
//
// ms = 0, means allow others (if any) to run.
//
void os::naked_short_sleep(jlong ms) {
  assert(ms < 1000, "Un-interruptable sleep, short time use only");
  Sleep(ms);
}

// 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);

void os::naked_yield() {
  // Use either SwitchToThread() or Sleep(0)
  // Consider passing back the return value from SwitchToThread().
  if (os::Kernel32Dll::SwitchToThreadAvailable()) {
    SwitchToThread();
  } else {
    Sleep(0);
  }
}

// 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[CriticalPriority + 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
  THREAD_PRIORITY_HIGHEST                       // 11 CriticalPriority
};

int prio_policy1[CriticalPriority + 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
  THREAD_PRIORITY_TIME_CRITICAL                 // 11 CriticalPriority
};

static int prio_init() {
  // If ThreadPriorityPolicy is 1, switch tables
  if (ThreadPriorityPolicy == 1) {
    int i;
    for (i = 0; i < CriticalPriority + 1; i++) {
      os::java_to_os_priority[i] = prio_policy1[i];
    }
  }
  if (UseCriticalJavaThreadPriority) {
    os::java_to_os_priority[MaxPriority] = os::java_to_os_priority[CriticalPriority];
  }
  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();
  // There is no synchronization between the setting of the interrupt
  // and it being cleared here. It is critical - see 6535709 - that
  // we only clear the interrupt state, and reset the interrupt event,
  // if we are going to report that we were indeed interrupted - else
  // an interrupt can be "lost", leading to spurious wakeups or lost wakeups
  // depending on the timing. By checking thread interrupt event to see
  // if the thread gets real interrupt thus prevent spurious wakeup.
  bool interrupted = osthread->interrupted() && (WaitForSingleObject(osthread->interrupt_event(), 0) == WAIT_OBJECT_0);
  if (interrupted && clear_interrupted) {
    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;
bool   os::win32::_is_windows_server         = false;

// 6573254
// Currently, the bug is observed across all the supported Windows releases,
// including the latest one (as of this writing - Windows Server 2012 R2)
bool   os::win32::_has_exit_bug              = true;
bool   os::win32::_has_performance_count     = 0;

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;
  set_processor_count(si.dwNumberOfProcessors);

  MEMORYSTATUSEX ms;
  ms.dwLength = sizeof(ms);

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

  OSVERSIONINFOEX oi;
  oi.dwOSVersionInfoSize = sizeof(OSVERSIONINFOEX);
  GetVersionEx((OSVERSIONINFO*)&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;
      }
      if (oi.wProductType == VER_NT_DOMAIN_CONTROLLER ||
          oi.wProductType == VER_NT_SERVER) {
        _is_windows_server = 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;
  }
}


HINSTANCE os::win32::load_Windows_dll(const char* name, char *ebuf,
                                      int ebuflen) {
  char path[MAX_PATH];
  DWORD size;
  DWORD pathLen = (DWORD)sizeof(path);
  HINSTANCE result = NULL;

  // only allow library name without path component
  assert(strchr(name, '\\') == NULL, "path not allowed");
  assert(strchr(name, ':') == NULL, "path not allowed");
  if (strchr(name, '\\') != NULL || strchr(name, ':') != NULL) {
    jio_snprintf(ebuf, ebuflen,
                 "Invalid parameter while calling os::win32::load_windows_dll(): cannot take path: %s", name);
    return NULL;
  }

  // search system directory
  if ((size = GetSystemDirectory(path, pathLen)) > 0) {
    strcat(path, "\\");
    strcat(path, name);
    if ((result = (HINSTANCE)os::dll_load(path, ebuf, ebuflen)) != NULL) {
      return result;
    }
  }

  // try Windows directory
  if ((size = GetWindowsDirectory(path, pathLen)) > 0) {
    strcat(path, "\\");
    strcat(path, name);
    if ((result = (HINSTANCE)os::dll_load(path, ebuf, ebuflen)) != NULL) {
      return result;
    }
  }

  jio_snprintf(ebuf, ebuflen,
               "os::win32::load_windows_dll() cannot load %s from system directories.", name);
  return NULL;
}

#define MIN_EXIT_MUTEXES 1
#define MAX_EXIT_MUTEXES 16

struct ExitMutexes {
  DWORD count;
  HANDLE handles[MAX_EXIT_MUTEXES];
};

static BOOL CALLBACK init_muts_call(PINIT_ONCE, PVOID ppmuts, PVOID*) {
  static ExitMutexes muts;

  muts.count = os::processor_count();
  if (muts.count < MIN_EXIT_MUTEXES) {
    muts.count = MIN_EXIT_MUTEXES;
  } else if (muts.count > MAX_EXIT_MUTEXES) {
    muts.count = MAX_EXIT_MUTEXES;
  }

  for (DWORD i = 0; i < muts.count; ++i) {
    muts.handles[i] = CreateMutex(NULL, FALSE, NULL);
    if (muts.handles[i] == NULL) {
      return FALSE;
    }
  }
  *((ExitMutexes**)ppmuts) = &muts;
  return TRUE;
}

int os::win32::exit_process_or_thread(Ept what, int exit_code) {
  if (os::win32::has_exit_bug()) {
    static INIT_ONCE init_once_muts = INIT_ONCE_STATIC_INIT;
    static ExitMutexes* pmuts;

    if (!InitOnceExecuteOnce(&init_once_muts, init_muts_call, &pmuts, NULL)) {
      warning("ExitMutex initialization failed in %s: %d\n", __FILE__, __LINE__);
    } else if (WaitForMultipleObjects(pmuts->count, pmuts->handles,
                                      (what != EPT_THREAD), // exiting process waits for all mutexes
                                      INFINITE) == WAIT_FAILED) {
      warning("ExitMutex acquisition failed in %s: %d\n", __FILE__, __LINE__);
    }
  }

  switch (what) {
  case EPT_THREAD:
    _endthreadex((unsigned)exit_code);
    break;

  case EPT_PROCESS:
    ::exit(exit_code);
    break;

  case EPT_PROCESS_DIE:
    _exit(exit_code);
    break;
  }

  // should not reach here
  return exit_code;
}

#undef MIN_EXIT_MUTEXES
#undef MAX_EXIT_MUTEXES

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


bool os::is_debugger_attached() {
  return IsDebuggerPresent() ? true : false;
}


void os::wait_for_keypress_at_exit(void) {
  if (PauseAtExit) {
    fprintf(stderr, "Press any key to continue...\n");
    fgetc(stdin);
  }
}


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());

  // 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();
  }
}

static jint initSock();

// 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_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_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
  }

  // Setup Windows Exceptions

  // 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
  }

  // 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;
  }

  // Check minimum allowable stack size for thread creation and to initialize
  // the java system classes, including StackOverflowError - depends on page
  // size.  Add a page for compiler2 recursion in main thread.
  // Add in 2*BytesPerWord times page size to account for VM stack during
  // class initialization depending on 32 or 64 bit VM.
  size_t min_stack_allowed =
            (size_t)(StackYellowPages+StackRedPages+StackShadowPages+
                     2*BytesPerWord COMPILER2_PRESENT(+1)) * os::vm_page_size();
  if (actual_reserve_size < min_stack_allowed) {
    tty->print_cr("\nThe stack size specified is too small, "
                  "Specify at least %dk",
                  min_stack_allowed / K);
    return JNI_ERR;
  }

  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");
    }
  }

#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; // We don't fully support this yet
  }

  if (UseNUMAInterleaving) {
    // first check whether this Windows OS supports VirtualAllocExNuma, if not ignore this flag
    bool success = numa_interleaving_init();
    if (!success) UseNUMAInterleaving = false;
  }

  if (initSock() != JNI_OK) {
    return JNI_ERR;
  }

  return JNI_OK;
}

void os::init_3(void) {
  return;
}

// 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;
  }
  os::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;
}

// This method is a slightly reworked copy of JDK's sysOpen
// from src/windows/hpi/src/sys_api_md.c

int os::open(const char *path, int oflag, int mode) {
  char pathbuf[MAX_PATH];

  if (strlen(path) > MAX_PATH - 1) {
    errno = ENAMETOOLONG;
    return -1;
  }
  os::native_path(strcpy(pathbuf, path));
  return ::open(pathbuf, oflag | O_BINARY | O_NOINHERIT, mode);
}

FILE* os::open(int fd, const char* mode) {
  return ::_fdopen(fd, mode);
}

// 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);
}


jlong os::lseek(int fd, jlong offset, int whence) {
  return (jlong) ::_lseeki64(fd, offset, whence);
}

// This method is a slightly reworked copy of JDK's sysNativePath
// from src/windows/hpi/src/path_md.c

// Convert a pathname to native format.  On win32, this involves forcing all
// separators to be '\\' rather than '/' (both are legal inputs, but Win95
// sometimes rejects '/') and removing redundant separators.  The input path is
// assumed to have been converted into the character encoding used by the local
// system.  Because this might be a double-byte encoding, care is taken to
// treat double-byte lead characters correctly.
//
// This procedure modifies the given path in place, as the result is never
// longer than the original.  There is no error return; this operation always
// succeeds.
char * os::native_path(char *path) {
  char *src = path, *dst = path, *end = path;
  char *colon = NULL;  // If a drive specifier is found, this will
                       // point to the colon following the drive letter

  // Assumption: '/', '\\', ':', and drive letters are never lead bytes
  assert(((!::IsDBCSLeadByte('/')) && (!::IsDBCSLeadByte('\\'))
          && (!::IsDBCSLeadByte(':'))), "Illegal lead byte");

  // Check for leading separators
#define isfilesep(c) ((c) == '/' || (c) == '\\')
  while (isfilesep(*src)) {
    src++;
  }

  if (::isalpha(*src) && !::IsDBCSLeadByte(*src) && src[1] == ':') {
    // Remove leading separators if followed by drive specifier.  This
    // hack is necessary to support file URLs containing drive
    // specifiers (e.g., "file://c:/path").  As a side effect,
    // "/c:/path" can be used as an alternative to "c:/path".
    *dst++ = *src++;
    colon = dst;
    *dst++ = ':';
    src++;
  } else {
    src = path;
    if (isfilesep(src[0]) && isfilesep(src[1])) {
      // UNC pathname: Retain first separator; leave src pointed at
      // second separator so that further separators will be collapsed
      // into the second separator.  The result will be a pathname
      // beginning with "\\\\" followed (most likely) by a host name.
      src = dst = path + 1;
      path[0] = '\\';     // Force first separator to '\\'
    }
  }

  end = dst;

  // Remove redundant separators from remainder of path, forcing all
  // separators to be '\\' rather than '/'. Also, single byte space
  // characters are removed from the end of the path because those
  // are not legal ending characters on this operating system.
  //
  while (*src != '\0') {
    if (isfilesep(*src)) {
      *dst++ = '\\'; src++;
      while (isfilesep(*src)) src++;
      if (*src == '\0') {
        // Check for trailing separator
        end = dst;
        if (colon == dst - 2) break;  // "z:\\"
        if (dst == path + 1) break;   // "\\"
        if (dst == path + 2 && isfilesep(path[0])) {
          // "\\\\" is not collapsed to "\\" because "\\\\" marks the
          // beginning of a UNC pathname.  Even though it is not, by
          // itself, a valid UNC pathname, we leave it as is in order
          // to be consistent with the path canonicalizer as well
          // as the win32 APIs, which treat this case as an invalid
          // UNC pathname rather than as an alias for the root
          // directory of the current drive.
          break;
        }
        end = --dst;  // Path does not denote a root directory, so
                      // remove trailing separator
        break;
      }
      end = dst;
    } else {
      if (::IsDBCSLeadByte(*src)) {  // Copy a double-byte character
        *dst++ = *src++;
        if (*src) *dst++ = *src++;
        end = dst;
      } else {  // Copy a single-byte character
        char c = *src++;
        *dst++ = c;
        // Space is not a legal ending character
        if (c != ' ') end = dst;
      }
    }
  }

  *end = '\0';

  // For "z:", add "." to work around a bug in the C runtime library
  if (colon == dst - 1) {
    path[2] = '.';
    path[3] = '\0';
  }

  return path;
}

// This code is a copy of JDK's sysSetLength
// from src/windows/hpi/src/sys_api_md.c

int os::ftruncate(int fd, jlong length) {
  HANDLE h = (HANDLE)::_get_osfhandle(fd);
  long high = (long)(length >> 32);
  DWORD ret;

  if (h == (HANDLE)(-1)) {
    return -1;
  }

  ret = ::SetFilePointer(h, (long)(length), &high, FILE_BEGIN);
  if ((ret == 0xFFFFFFFF) && (::GetLastError() != NO_ERROR)) {
    return -1;
  }

  if (::SetEndOfFile(h) == FALSE) {
    return -1;
  }

  return 0;
}


// This code is a copy of JDK's sysSync
// from src/windows/hpi/src/sys_api_md.c
// except for the legacy workaround for a bug in Win 98

int os::fsync(int fd) {
  HANDLE handle = (HANDLE)::_get_osfhandle(fd);

  if ((!::FlushFileBuffers(handle)) &&
      (GetLastError() != ERROR_ACCESS_DENIED)) {
    // from winerror.h
    return -1;
  }
  return 0;
}

static int nonSeekAvailable(int, long *);
static int stdinAvailable(int, long *);

#define S_ISCHR(mode)   (((mode) & _S_IFCHR) == _S_IFCHR)
#define S_ISFIFO(mode)  (((mode) & _S_IFIFO) == _S_IFIFO)

// This code is a copy of JDK's sysAvailable
// from src/windows/hpi/src/sys_api_md.c

int os::available(int fd, jlong *bytes) {
  jlong cur, end;
  struct _stati64 stbuf64;

  if (::_fstati64(fd, &stbuf64) >= 0) {
    int mode = stbuf64.st_mode;
    if (S_ISCHR(mode) || S_ISFIFO(mode)) {
      int ret;
      long lpbytes;
      if (fd == 0) {
        ret = stdinAvailable(fd, &lpbytes);
      } else {
        ret = nonSeekAvailable(fd, &lpbytes);
      }
      (*bytes) = (jlong)(lpbytes);
      return ret;
    }
    if ((cur = ::_lseeki64(fd, 0L, SEEK_CUR)) == -1) {
      return FALSE;
    } else if ((end = ::_lseeki64(fd, 0L, SEEK_END)) == -1) {
      return FALSE;
    } else if (::_lseeki64(fd, cur, SEEK_SET) == -1) {
      return FALSE;
    }
    *bytes = end - cur;
    return TRUE;
  } else {
    return FALSE;
  }
}

// This code is a copy of JDK's nonSeekAvailable
// from src/windows/hpi/src/sys_api_md.c

static int nonSeekAvailable(int fd, long *pbytes) {
  // This is used for available on non-seekable devices
  // (like both named and anonymous pipes, such as pipes
  //  connected to an exec'd process).
  // Standard Input is a special case.
  HANDLE han;

  if ((han = (HANDLE) ::_get_osfhandle(fd)) == (HANDLE)(-1)) {
    return FALSE;
  }

  if (! ::PeekNamedPipe(han, NULL, 0, NULL, (LPDWORD)pbytes, NULL)) {
    // PeekNamedPipe fails when at EOF.  In that case we
    // simply make *pbytes = 0 which is consistent with the
    // behavior we get on Solaris when an fd is at EOF.
    // The only alternative is to raise an Exception,
    // which isn't really warranted.
    //
    if (::GetLastError() != ERROR_BROKEN_PIPE) {
      return FALSE;
    }
    *pbytes = 0;
  }
  return TRUE;
}

#define MAX_INPUT_EVENTS 2000

// This code is a copy of JDK's stdinAvailable
// from src/windows/hpi/src/sys_api_md.c

static int stdinAvailable(int fd, long *pbytes) {
  HANDLE han;
  DWORD numEventsRead = 0;  // Number of events read from buffer
  DWORD numEvents = 0;      // Number of events in buffer
  DWORD i = 0;              // Loop index
  DWORD curLength = 0;      // Position marker
  DWORD actualLength = 0;   // Number of bytes readable
  BOOL error = FALSE;       // Error holder
  INPUT_RECORD *lpBuffer;   // Pointer to records of input events

  if ((han = ::GetStdHandle(STD_INPUT_HANDLE)) == INVALID_HANDLE_VALUE) {
    return FALSE;
  }

  // Construct an array of input records in the console buffer
  error = ::GetNumberOfConsoleInputEvents(han, &numEvents);
  if (error == 0) {
    return nonSeekAvailable(fd, pbytes);
  }

  // lpBuffer must fit into 64K or else PeekConsoleInput fails
  if (numEvents > MAX_INPUT_EVENTS) {
    numEvents = MAX_INPUT_EVENTS;
  }

  lpBuffer = (INPUT_RECORD *)os::malloc(numEvents * sizeof(INPUT_RECORD), mtInternal);
  if (lpBuffer == NULL) {
    return FALSE;
  }

  error = ::PeekConsoleInput(han, lpBuffer, numEvents, &numEventsRead);
  if (error == 0) {
    os::free(lpBuffer, mtInternal);
    return FALSE;
  }

  // Examine input records for the number of bytes available
  for (i=0; i<numEvents; i++) {
    if (lpBuffer[i].EventType == KEY_EVENT) {

      KEY_EVENT_RECORD *keyRecord = (KEY_EVENT_RECORD *)
                                      &(lpBuffer[i].Event);
      if (keyRecord->bKeyDown == TRUE) {
        CHAR *keyPressed = (CHAR *) &(keyRecord->uChar);
        curLength++;
        if (*keyPressed == '\r') {
          actualLength = curLength;
        }
      }
    }
  }

  if (lpBuffer != NULL) {
    os::free(lpBuffer, mtInternal);
  }

  *pbytes = (long) actualLength;
  return TRUE;
}

// Map a block of memory.
char* os::pd_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.", err);
    }
    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.", err);
      }
      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::pd_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::pd_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);
  }
}

os::WatcherThreadCrashProtection::WatcherThreadCrashProtection() {
  assert(Thread::current()->is_Watcher_thread(), "Must be WatcherThread");
}

// See the caveats for this class in os_windows.hpp
// Protects the callback call so that raised OS EXCEPTIONS causes a jump back
// into this method and returns false. If no OS EXCEPTION was raised, returns
// true.
// The callback is supposed to provide the method that should be protected.
//
bool os::WatcherThreadCrashProtection::call(os::CrashProtectionCallback& cb) {
  assert(Thread::current()->is_Watcher_thread(), "Only for WatcherThread");
  assert(!WatcherThread::watcher_thread()->has_crash_protection(),
         "crash_protection already set?");

  bool success = true;
  __try {
    WatcherThread::watcher_thread()->set_crash_protection(this);
    cb.call();
  } __except(EXCEPTION_EXECUTE_HANDLER) {
    // only for protection, nothing to do
    success = false;
  }
  WatcherThread::watcher_thread()->set_crash_protection(NULL);
  return success;
}

// 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;
  // see comment at end of os::PlatformEvent::park() below:
  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");

  // Transitions for _Event:
  //    0 :=> 1
  //    1 :=> 1
  //   -1 :=> either 0 or 1; must signal target thread
  //          That is, we can safely transition _Event from -1 to either
  //          0 or 1.
  // See also: "Semaphores in Plan 9" by Mullender & Cox
  //
  // Note: Forcing a transition from "-1" to "1" on an unpark() means
  // that it will take two back-to-back park() calls for the owning
  // thread to block. This has the benefit of forcing a spurious return
  // from the first park() call after an unpark() call which will help
  // shake out uses of park() and unpark() without condition variables.

  if (Atomic::xchg(1, &_Event) >= 0) return;

  ::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 && !isAbsolute) {
    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();

    // If we fail to lock the heap, then gflags.exe has been used
    // or some other special heap flag has been set that prevents
    // locking. We don't try to walk a heap we can't lock.
    if (HeapLock(heap) != 0) {
      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");
        }
      }
      DWORD err = GetLastError();
      if (err != ERROR_NO_MORE_ITEMS && err != ERROR_CALL_NOT_IMPLEMENTED) {
        fatal(err_msg("heap walk aborted with error %d", err));
      }
      HeapUnlock(heap);
    }
    mallocDebugIntervalCounter = 0;
  }
  return true;
}


bool os::find(address addr, outputStream* st) {
  // Nothing yet
  return false;
}

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;
}

// We don't build a headless jre for Windows
bool os::is_headless_jre() { return false; }

static jint initSock() {
  WSADATA wsadata;

  if (!os::WinSock2Dll::WinSock2Available()) {
    jio_fprintf(stderr, "Could not load Winsock (error: %d)\n",
                ::GetLastError());
    return JNI_ERR;
  }

  if (os::WinSock2Dll::WSAStartup(MAKEWORD(2,2), &wsadata) != 0) {
    jio_fprintf(stderr, "Could not initialize Winsock (error: %d)\n",
                ::GetLastError());
    return JNI_ERR;
  }
  return JNI_OK;
}

struct hostent* os::get_host_by_name(char* name) {
  return (struct hostent*)os::WinSock2Dll::gethostbyname(name);
}

int os::socket_close(int fd) {
  return ::closesocket(fd);
}

int os::socket_available(int fd, jint *pbytes) {
  int ret = ::ioctlsocket(fd, FIONREAD, (u_long*)pbytes);
  return (ret < 0) ? 0 : 1;
}

int os::socket(int domain, int type, int protocol) {
  return ::socket(domain, type, protocol);
}

int os::listen(int fd, int count) {
  return ::listen(fd, count);
}

int os::connect(int fd, struct sockaddr* him, socklen_t len) {
  return ::connect(fd, him, len);
}

int os::accept(int fd, struct sockaddr* him, socklen_t* len) {
  return ::accept(fd, him, len);
}

int os::sendto(int fd, char* buf, size_t len, uint flags,
               struct sockaddr* to, socklen_t tolen) {

  return ::sendto(fd, buf, (int)len, flags, to, tolen);
}

int os::recvfrom(int fd, char *buf, size_t nBytes, uint flags,
                 sockaddr* from, socklen_t* fromlen) {

  return ::recvfrom(fd, buf, (int)nBytes, flags, from, fromlen);
}

int os::recv(int fd, char* buf, size_t nBytes, uint flags) {
  return ::recv(fd, buf, (int)nBytes, flags);
}

int os::send(int fd, char* buf, size_t nBytes, uint flags) {
  return ::send(fd, buf, (int)nBytes, flags);
}

int os::raw_send(int fd, char* buf, size_t nBytes, uint flags) {
  return ::send(fd, buf, (int)nBytes, flags);
}

int os::timeout(int fd, long timeout) {
  fd_set tbl;
  struct timeval t;

  t.tv_sec  = timeout / 1000;
  t.tv_usec = (timeout % 1000) * 1000;

  tbl.fd_count    = 1;
  tbl.fd_array[0] = fd;

  return ::select(1, &tbl, 0, 0, &t);
}

int os::get_host_name(char* name, int namelen) {
  return ::gethostname(name, namelen);
}

int os::socket_shutdown(int fd, int howto) {
  return ::shutdown(fd, howto);
}

int os::bind(int fd, struct sockaddr* him, socklen_t len) {
  return ::bind(fd, him, len);
}

int os::get_sock_name(int fd, struct sockaddr* him, socklen_t* len) {
  return ::getsockname(fd, him, len);
}

int os::get_sock_opt(int fd, int level, int optname,
                     char* optval, socklen_t* optlen) {
  return ::getsockopt(fd, level, optname, optval, optlen);
}

int os::set_sock_opt(int fd, int level, int optname,
                     const char* optval, socklen_t optlen) {
  return ::setsockopt(fd, level, optname, optval, optlen);
}

// WINDOWS CONTEXT Flags for THREAD_SAMPLING
#if defined(IA32)
  #define sampling_context_flags (CONTEXT_FULL | CONTEXT_FLOATING_POINT | CONTEXT_EXTENDED_REGISTERS)
#elif defined (AMD64)
  #define sampling_context_flags (CONTEXT_FULL | CONTEXT_FLOATING_POINT)
#endif

// returns true if thread could be suspended,
// false otherwise
static bool do_suspend(HANDLE* h) {
  if (h != NULL) {
    if (SuspendThread(*h) != ~0) {
      return true;
    }
  }
  return false;
}

// resume the thread
// calling resume on an active thread is a no-op
static void do_resume(HANDLE* h) {
  if (h != NULL) {
    ResumeThread(*h);
  }
}

// retrieve a suspend/resume context capable handle
// from the tid. Caller validates handle return value.
void get_thread_handle_for_extended_context(HANDLE* h,
                                            OSThread::thread_id_t tid) {
  if (h != NULL) {
    *h = OpenThread(THREAD_SUSPEND_RESUME | THREAD_GET_CONTEXT | THREAD_QUERY_INFORMATION, FALSE, tid);
  }
}

// Thread sampling implementation
//
void os::SuspendedThreadTask::internal_do_task() {
  CONTEXT    ctxt;
  HANDLE     h = NULL;

  // get context capable handle for thread
  get_thread_handle_for_extended_context(&h, _thread->osthread()->thread_id());

  // sanity
  if (h == NULL || h == INVALID_HANDLE_VALUE) {
    return;
  }

  // suspend the thread
  if (do_suspend(&h)) {
    ctxt.ContextFlags = sampling_context_flags;
    // get thread context
    GetThreadContext(h, &ctxt);
    SuspendedThreadTaskContext context(_thread, &ctxt);
    // pass context to Thread Sampling impl
    do_task(context);
    // resume thread
    do_resume(&h);
  }

  // close handle
  CloseHandle(h);
}


// Kernel32 API
typedef SIZE_T (WINAPI* GetLargePageMinimum_Fn)(void);
typedef LPVOID (WINAPI *VirtualAllocExNuma_Fn)(HANDLE, LPVOID, SIZE_T, DWORD, DWORD, DWORD);
typedef BOOL (WINAPI *GetNumaHighestNodeNumber_Fn)(PULONG);
typedef BOOL (WINAPI *GetNumaNodeProcessorMask_Fn)(UCHAR, PULONGLONG);
typedef USHORT (WINAPI* RtlCaptureStackBackTrace_Fn)(ULONG, ULONG, PVOID*, PULONG);

GetLargePageMinimum_Fn      os::Kernel32Dll::_GetLargePageMinimum = NULL;
VirtualAllocExNuma_Fn       os::Kernel32Dll::_VirtualAllocExNuma = NULL;
GetNumaHighestNodeNumber_Fn os::Kernel32Dll::_GetNumaHighestNodeNumber = NULL;
GetNumaNodeProcessorMask_Fn os::Kernel32Dll::_GetNumaNodeProcessorMask = NULL;
RtlCaptureStackBackTrace_Fn os::Kernel32Dll::_RtlCaptureStackBackTrace = NULL;


BOOL                        os::Kernel32Dll::initialized = FALSE;
SIZE_T os::Kernel32Dll::GetLargePageMinimum() {
  assert(initialized && _GetLargePageMinimum != NULL,
         "GetLargePageMinimumAvailable() not yet called");
  return _GetLargePageMinimum();
}

BOOL os::Kernel32Dll::GetLargePageMinimumAvailable() {
  if (!initialized) {
    initialize();
  }
  return _GetLargePageMinimum != NULL;
}

BOOL os::Kernel32Dll::NumaCallsAvailable() {
  if (!initialized) {
    initialize();
  }
  return _VirtualAllocExNuma != NULL;
}

LPVOID os::Kernel32Dll::VirtualAllocExNuma(HANDLE hProc, LPVOID addr,
                                           SIZE_T bytes, DWORD flags,
                                           DWORD prot, DWORD node) {
  assert(initialized && _VirtualAllocExNuma != NULL,
         "NUMACallsAvailable() not yet called");

  return _VirtualAllocExNuma(hProc, addr, bytes, flags, prot, node);
}

BOOL os::Kernel32Dll::GetNumaHighestNodeNumber(PULONG ptr_highest_node_number) {
  assert(initialized && _GetNumaHighestNodeNumber != NULL,
         "NUMACallsAvailable() not yet called");

  return _GetNumaHighestNodeNumber(ptr_highest_node_number);
}

BOOL os::Kernel32Dll::GetNumaNodeProcessorMask(UCHAR node,
                                               PULONGLONG proc_mask) {
  assert(initialized && _GetNumaNodeProcessorMask != NULL,
         "NUMACallsAvailable() not yet called");

  return _GetNumaNodeProcessorMask(node, proc_mask);
}

USHORT os::Kernel32Dll::RtlCaptureStackBackTrace(ULONG FrameToSkip,
                                                 ULONG FrameToCapture,
                                                 PVOID* BackTrace,
                                                 PULONG BackTraceHash) {
  if (!initialized) {
    initialize();
  }

  if (_RtlCaptureStackBackTrace != NULL) {
    return _RtlCaptureStackBackTrace(FrameToSkip, FrameToCapture,
                                     BackTrace, BackTraceHash);
  } else {
    return 0;
  }
}

void os::Kernel32Dll::initializeCommon() {
  if (!initialized) {
    HMODULE handle = ::GetModuleHandle("Kernel32.dll");
    assert(handle != NULL, "Just check");
    _GetLargePageMinimum = (GetLargePageMinimum_Fn)::GetProcAddress(handle, "GetLargePageMinimum");
    _VirtualAllocExNuma = (VirtualAllocExNuma_Fn)::GetProcAddress(handle, "VirtualAllocExNuma");
    _GetNumaHighestNodeNumber = (GetNumaHighestNodeNumber_Fn)::GetProcAddress(handle, "GetNumaHighestNodeNumber");
    _GetNumaNodeProcessorMask = (GetNumaNodeProcessorMask_Fn)::GetProcAddress(handle, "GetNumaNodeProcessorMask");
    _RtlCaptureStackBackTrace = (RtlCaptureStackBackTrace_Fn)::GetProcAddress(handle, "RtlCaptureStackBackTrace");
    initialized = TRUE;
  }
}



#ifndef JDK6_OR_EARLIER

void os::Kernel32Dll::initialize() {
  initializeCommon();
}


// Kernel32 API
inline BOOL os::Kernel32Dll::SwitchToThread() {
  return ::SwitchToThread();
}

inline BOOL os::Kernel32Dll::SwitchToThreadAvailable() {
  return true;
}

// Help tools
inline BOOL os::Kernel32Dll::HelpToolsAvailable() {
  return true;
}

inline HANDLE os::Kernel32Dll::CreateToolhelp32Snapshot(DWORD dwFlags,
                                                        DWORD th32ProcessId) {
  return ::CreateToolhelp32Snapshot(dwFlags, th32ProcessId);
}

inline BOOL os::Kernel32Dll::Module32First(HANDLE hSnapshot,
                                           LPMODULEENTRY32 lpme) {
  return ::Module32First(hSnapshot, lpme);
}

inline BOOL os::Kernel32Dll::Module32Next(HANDLE hSnapshot,
                                          LPMODULEENTRY32 lpme) {
  return ::Module32Next(hSnapshot, lpme);
}


inline BOOL os::Kernel32Dll::GetNativeSystemInfoAvailable() {
  return true;
}

inline void os::Kernel32Dll::GetNativeSystemInfo(LPSYSTEM_INFO lpSystemInfo) {
  ::GetNativeSystemInfo(lpSystemInfo);
}

// PSAPI API
inline BOOL os::PSApiDll::EnumProcessModules(HANDLE hProcess,
                                             HMODULE *lpModule, DWORD cb,
                                             LPDWORD lpcbNeeded) {
  return ::EnumProcessModules(hProcess, lpModule, cb, lpcbNeeded);
}

inline DWORD os::PSApiDll::GetModuleFileNameEx(HANDLE hProcess,
                                               HMODULE hModule,
                                               LPTSTR lpFilename,
                                               DWORD nSize) {
  return ::GetModuleFileNameEx(hProcess, hModule, lpFilename, nSize);
}

inline BOOL os::PSApiDll::GetModuleInformation(HANDLE hProcess,
                                               HMODULE hModule,
                                               LPMODULEINFO lpmodinfo,
                                               DWORD cb) {
  return ::GetModuleInformation(hProcess, hModule, lpmodinfo, cb);
}

inline BOOL os::PSApiDll::PSApiAvailable() {
  return true;
}


// WinSock2 API
inline BOOL os::WinSock2Dll::WSAStartup(WORD wVersionRequested,
                                        LPWSADATA lpWSAData) {
  return ::WSAStartup(wVersionRequested, lpWSAData);
}

inline struct hostent* os::WinSock2Dll::gethostbyname(const char *name) {
  return ::gethostbyname(name);
}

inline BOOL os::WinSock2Dll::WinSock2Available() {
  return true;
}

// Advapi API
inline BOOL os::Advapi32Dll::AdjustTokenPrivileges(HANDLE TokenHandle,
                                                   BOOL DisableAllPrivileges,
                                                   PTOKEN_PRIVILEGES NewState,
                                                   DWORD BufferLength,
                                                   PTOKEN_PRIVILEGES PreviousState,
                                                   PDWORD ReturnLength) {
  return ::AdjustTokenPrivileges(TokenHandle, DisableAllPrivileges, NewState,
                                 BufferLength, PreviousState, ReturnLength);
}

inline BOOL os::Advapi32Dll::OpenProcessToken(HANDLE ProcessHandle,
                                              DWORD DesiredAccess,
                                              PHANDLE TokenHandle) {
  return ::OpenProcessToken(ProcessHandle, DesiredAccess, TokenHandle);
}

inline BOOL os::Advapi32Dll::LookupPrivilegeValue(LPCTSTR lpSystemName,
                                                  LPCTSTR lpName,
                                                  PLUID lpLuid) {
  return ::LookupPrivilegeValue(lpSystemName, lpName, lpLuid);
}

inline BOOL os::Advapi32Dll::AdvapiAvailable() {
  return true;
}

void* os::get_default_process_handle() {
  return (void*)GetModuleHandle(NULL);
}

// Builds a platform dependent Agent_OnLoad_<lib_name> function name
// which is used to find statically linked in agents.
// Additionally for windows, takes into account __stdcall names.
// Parameters:
//            sym_name: Symbol in library we are looking for
//            lib_name: Name of library to look in, NULL for shared libs.
//            is_absolute_path == true if lib_name is absolute path to agent
//                                     such as "C:/a/b/L.dll"
//            == false if only the base name of the library is passed in
//               such as "L"
char* os::build_agent_function_name(const char *sym_name, const char *lib_name,
                                    bool is_absolute_path) {
  char *agent_entry_name;
  size_t len;
  size_t name_len;
  size_t prefix_len = strlen(JNI_LIB_PREFIX);
  size_t suffix_len = strlen(JNI_LIB_SUFFIX);
  const char *start;

  if (lib_name != NULL) {
    len = name_len = strlen(lib_name);
    if (is_absolute_path) {
      // Need to strip path, prefix and suffix
      if ((start = strrchr(lib_name, *os::file_separator())) != NULL) {
        lib_name = ++start;
      } else {
        // Need to check for drive prefix
        if ((start = strchr(lib_name, ':')) != NULL) {
          lib_name = ++start;
        }
      }
      if (len <= (prefix_len + suffix_len)) {
        return NULL;
      }
      lib_name += prefix_len;
      name_len = strlen(lib_name) - suffix_len;
    }
  }
  len = (lib_name != NULL ? name_len : 0) + strlen(sym_name) + 2;
  agent_entry_name = NEW_C_HEAP_ARRAY_RETURN_NULL(char, len, mtThread);
  if (agent_entry_name == NULL) {
    return NULL;
  }
  if (lib_name != NULL) {
    const char *p = strrchr(sym_name, '@');
    if (p != NULL && p != sym_name) {
      // sym_name == _Agent_OnLoad@XX
      strncpy(agent_entry_name, sym_name, (p - sym_name));
      agent_entry_name[(p-sym_name)] = '\0';
      // agent_entry_name == _Agent_OnLoad
      strcat(agent_entry_name, "_");
      strncat(agent_entry_name, lib_name, name_len);
      strcat(agent_entry_name, p);
      // agent_entry_name == _Agent_OnLoad_lib_name@XX
    } else {
      strcpy(agent_entry_name, sym_name);
      strcat(agent_entry_name, "_");
      strncat(agent_entry_name, lib_name, name_len);
    }
  } else {
    strcpy(agent_entry_name, sym_name);
  }
  return agent_entry_name;
}

#else
// Kernel32 API
typedef BOOL (WINAPI* SwitchToThread_Fn)(void);
typedef HANDLE (WINAPI* CreateToolhelp32Snapshot_Fn)(DWORD, DWORD);
typedef BOOL (WINAPI* Module32First_Fn)(HANDLE, LPMODULEENTRY32);
typedef BOOL (WINAPI* Module32Next_Fn)(HANDLE, LPMODULEENTRY32);
typedef void (WINAPI* GetNativeSystemInfo_Fn)(LPSYSTEM_INFO);

SwitchToThread_Fn           os::Kernel32Dll::_SwitchToThread = NULL;
CreateToolhelp32Snapshot_Fn os::Kernel32Dll::_CreateToolhelp32Snapshot = NULL;
Module32First_Fn            os::Kernel32Dll::_Module32First = NULL;
Module32Next_Fn             os::Kernel32Dll::_Module32Next = NULL;
GetNativeSystemInfo_Fn      os::Kernel32Dll::_GetNativeSystemInfo = NULL;

void os::Kernel32Dll::initialize() {
  if (!initialized) {
    HMODULE handle = ::GetModuleHandle("Kernel32.dll");
    assert(handle != NULL, "Just check");

    _SwitchToThread = (SwitchToThread_Fn)::GetProcAddress(handle, "SwitchToThread");
    _CreateToolhelp32Snapshot = (CreateToolhelp32Snapshot_Fn)
      ::GetProcAddress(handle, "CreateToolhelp32Snapshot");
    _Module32First = (Module32First_Fn)::GetProcAddress(handle, "Module32First");
    _Module32Next = (Module32Next_Fn)::GetProcAddress(handle, "Module32Next");
    _GetNativeSystemInfo = (GetNativeSystemInfo_Fn)::GetProcAddress(handle, "GetNativeSystemInfo");
    initializeCommon();  // resolve the functions that always need resolving

    initialized = TRUE;
  }
}

BOOL os::Kernel32Dll::SwitchToThread() {
  assert(initialized && _SwitchToThread != NULL,
         "SwitchToThreadAvailable() not yet called");
  return _SwitchToThread();
}


BOOL os::Kernel32Dll::SwitchToThreadAvailable() {
  if (!initialized) {
    initialize();
  }
  return _SwitchToThread != NULL;
}

// Help tools
BOOL os::Kernel32Dll::HelpToolsAvailable() {
  if (!initialized) {
    initialize();
  }
  return _CreateToolhelp32Snapshot != NULL &&
         _Module32First != NULL &&
         _Module32Next != NULL;
}

HANDLE os::Kernel32Dll::CreateToolhelp32Snapshot(DWORD dwFlags,
                                                 DWORD th32ProcessId) {
  assert(initialized && _CreateToolhelp32Snapshot != NULL,
         "HelpToolsAvailable() not yet called");

  return _CreateToolhelp32Snapshot(dwFlags, th32ProcessId);
}

BOOL os::Kernel32Dll::Module32First(HANDLE hSnapshot,LPMODULEENTRY32 lpme) {
  assert(initialized && _Module32First != NULL,
         "HelpToolsAvailable() not yet called");

  return _Module32First(hSnapshot, lpme);
}

inline BOOL os::Kernel32Dll::Module32Next(HANDLE hSnapshot,
                                          LPMODULEENTRY32 lpme) {
  assert(initialized && _Module32Next != NULL,
         "HelpToolsAvailable() not yet called");

  return _Module32Next(hSnapshot, lpme);
}


BOOL os::Kernel32Dll::GetNativeSystemInfoAvailable() {
  if (!initialized) {
    initialize();
  }
  return _GetNativeSystemInfo != NULL;
}

void os::Kernel32Dll::GetNativeSystemInfo(LPSYSTEM_INFO lpSystemInfo) {
  assert(initialized && _GetNativeSystemInfo != NULL,
         "GetNativeSystemInfoAvailable() not yet called");

  _GetNativeSystemInfo(lpSystemInfo);
}

// PSAPI API


typedef BOOL (WINAPI *EnumProcessModules_Fn)(HANDLE, HMODULE *, DWORD, LPDWORD);
typedef BOOL (WINAPI *GetModuleFileNameEx_Fn)(HANDLE, HMODULE, LPTSTR, DWORD);
typedef BOOL (WINAPI *GetModuleInformation_Fn)(HANDLE, HMODULE, LPMODULEINFO, DWORD);

EnumProcessModules_Fn   os::PSApiDll::_EnumProcessModules = NULL;
GetModuleFileNameEx_Fn  os::PSApiDll::_GetModuleFileNameEx = NULL;
GetModuleInformation_Fn os::PSApiDll::_GetModuleInformation = NULL;
BOOL                    os::PSApiDll::initialized = FALSE;

void os::PSApiDll::initialize() {
  if (!initialized) {
    HMODULE handle = os::win32::load_Windows_dll("PSAPI.DLL", NULL, 0);
    if (handle != NULL) {
      _EnumProcessModules = (EnumProcessModules_Fn)::GetProcAddress(handle,
                                                                    "EnumProcessModules");
      _GetModuleFileNameEx = (GetModuleFileNameEx_Fn)::GetProcAddress(handle,
                                                                      "GetModuleFileNameExA");
      _GetModuleInformation = (GetModuleInformation_Fn)::GetProcAddress(handle,
                                                                        "GetModuleInformation");
    }
    initialized = TRUE;
  }
}



BOOL os::PSApiDll::EnumProcessModules(HANDLE hProcess, HMODULE *lpModule,
                                      DWORD cb, LPDWORD lpcbNeeded) {
  assert(initialized && _EnumProcessModules != NULL,
         "PSApiAvailable() not yet called");
  return _EnumProcessModules(hProcess, lpModule, cb, lpcbNeeded);
}

DWORD os::PSApiDll::GetModuleFileNameEx(HANDLE hProcess, HMODULE hModule,
                                        LPTSTR lpFilename, DWORD nSize) {
  assert(initialized && _GetModuleFileNameEx != NULL,
         "PSApiAvailable() not yet called");
  return _GetModuleFileNameEx(hProcess, hModule, lpFilename, nSize);
}

BOOL os::PSApiDll::GetModuleInformation(HANDLE hProcess, HMODULE hModule,
                                        LPMODULEINFO lpmodinfo, DWORD cb) {
  assert(initialized && _GetModuleInformation != NULL,
         "PSApiAvailable() not yet called");
  return _GetModuleInformation(hProcess, hModule, lpmodinfo, cb);
}

BOOL os::PSApiDll::PSApiAvailable() {
  if (!initialized) {
    initialize();
  }
  return _EnumProcessModules != NULL &&
    _GetModuleFileNameEx != NULL &&
    _GetModuleInformation != NULL;
}


// WinSock2 API
typedef int (PASCAL FAR* WSAStartup_Fn)(WORD, LPWSADATA);
typedef struct hostent *(PASCAL FAR *gethostbyname_Fn)(...);

WSAStartup_Fn    os::WinSock2Dll::_WSAStartup = NULL;
gethostbyname_Fn os::WinSock2Dll::_gethostbyname = NULL;
BOOL             os::WinSock2Dll::initialized = FALSE;

void os::WinSock2Dll::initialize() {
  if (!initialized) {
    HMODULE handle = os::win32::load_Windows_dll("ws2_32.dll", NULL, 0);
    if (handle != NULL) {
      _WSAStartup = (WSAStartup_Fn)::GetProcAddress(handle, "WSAStartup");
      _gethostbyname = (gethostbyname_Fn)::GetProcAddress(handle, "gethostbyname");
    }
    initialized = TRUE;
  }
}


BOOL os::WinSock2Dll::WSAStartup(WORD wVersionRequested, LPWSADATA lpWSAData) {
  assert(initialized && _WSAStartup != NULL,
         "WinSock2Available() not yet called");
  return _WSAStartup(wVersionRequested, lpWSAData);
}

struct hostent* os::WinSock2Dll::gethostbyname(const char *name) {
  assert(initialized && _gethostbyname != NULL,
         "WinSock2Available() not yet called");
  return _gethostbyname(name);
}

BOOL os::WinSock2Dll::WinSock2Available() {
  if (!initialized) {
    initialize();
  }
  return _WSAStartup != NULL &&
    _gethostbyname != NULL;
}

typedef BOOL (WINAPI *AdjustTokenPrivileges_Fn)(HANDLE, BOOL, PTOKEN_PRIVILEGES, DWORD, PTOKEN_PRIVILEGES, PDWORD);
typedef BOOL (WINAPI *OpenProcessToken_Fn)(HANDLE, DWORD, PHANDLE);
typedef BOOL (WINAPI *LookupPrivilegeValue_Fn)(LPCTSTR, LPCTSTR, PLUID);

AdjustTokenPrivileges_Fn os::Advapi32Dll::_AdjustTokenPrivileges = NULL;
OpenProcessToken_Fn      os::Advapi32Dll::_OpenProcessToken = NULL;
LookupPrivilegeValue_Fn  os::Advapi32Dll::_LookupPrivilegeValue = NULL;
BOOL                     os::Advapi32Dll::initialized = FALSE;

void os::Advapi32Dll::initialize() {
  if (!initialized) {
    HMODULE handle = os::win32::load_Windows_dll("advapi32.dll", NULL, 0);
    if (handle != NULL) {
      _AdjustTokenPrivileges = (AdjustTokenPrivileges_Fn)::GetProcAddress(handle,
                                                                          "AdjustTokenPrivileges");
      _OpenProcessToken = (OpenProcessToken_Fn)::GetProcAddress(handle,
                                                                "OpenProcessToken");
      _LookupPrivilegeValue = (LookupPrivilegeValue_Fn)::GetProcAddress(handle,
                                                                        "LookupPrivilegeValueA");
    }
    initialized = TRUE;
  }
}

BOOL os::Advapi32Dll::AdjustTokenPrivileges(HANDLE TokenHandle,
                                            BOOL DisableAllPrivileges,
                                            PTOKEN_PRIVILEGES NewState,
                                            DWORD BufferLength,
                                            PTOKEN_PRIVILEGES PreviousState,
                                            PDWORD ReturnLength) {
  assert(initialized && _AdjustTokenPrivileges != NULL,
         "AdvapiAvailable() not yet called");
  return _AdjustTokenPrivileges(TokenHandle, DisableAllPrivileges, NewState,
                                BufferLength, PreviousState, ReturnLength);
}

BOOL os::Advapi32Dll::OpenProcessToken(HANDLE ProcessHandle,
                                       DWORD DesiredAccess,
                                       PHANDLE TokenHandle) {
  assert(initialized && _OpenProcessToken != NULL,
         "AdvapiAvailable() not yet called");
  return _OpenProcessToken(ProcessHandle, DesiredAccess, TokenHandle);
}

BOOL os::Advapi32Dll::LookupPrivilegeValue(LPCTSTR lpSystemName,
                                           LPCTSTR lpName, PLUID lpLuid) {
  assert(initialized && _LookupPrivilegeValue != NULL,
         "AdvapiAvailable() not yet called");
  return _LookupPrivilegeValue(lpSystemName, lpName, lpLuid);
}

BOOL os::Advapi32Dll::AdvapiAvailable() {
  if (!initialized) {
    initialize();
  }
  return _AdjustTokenPrivileges != NULL &&
    _OpenProcessToken != NULL &&
    _LookupPrivilegeValue != NULL;
}

#endif

#ifndef PRODUCT

// test the code path in reserve_memory_special() that tries to allocate memory in a single
// contiguous memory block at a particular address.
// The test first tries to find a good approximate address to allocate at by using the same
// method to allocate some memory at any address. The test then tries to allocate memory in
// the vicinity (not directly after it to avoid possible by-chance use of that location)
// This is of course only some dodgy assumption, there is no guarantee that the vicinity of
// the previously allocated memory is available for allocation. The only actual failure
// that is reported is when the test tries to allocate at a particular location but gets a
// different valid one. A NULL return value at this point is not considered an error but may
// be legitimate.
// If -XX:+VerboseInternalVMTests is enabled, print some explanatory messages.
void TestReserveMemorySpecial_test() {
  if (!UseLargePages) {
    if (VerboseInternalVMTests) {
      gclog_or_tty->print("Skipping test because large pages are disabled");
    }
    return;
  }
  // save current value of globals
  bool old_use_large_pages_individual_allocation = UseLargePagesIndividualAllocation;
  bool old_use_numa_interleaving = UseNUMAInterleaving;

  // set globals to make sure we hit the correct code path
  UseLargePagesIndividualAllocation = UseNUMAInterleaving = false;

  // do an allocation at an address selected by the OS to get a good one.
  const size_t large_allocation_size = os::large_page_size() * 4;
  char* result = os::reserve_memory_special(large_allocation_size, os::large_page_size(), NULL, false);
  if (result == NULL) {
    if (VerboseInternalVMTests) {
      gclog_or_tty->print("Failed to allocate control block with size "SIZE_FORMAT". Skipping remainder of test.",
                          large_allocation_size);
    }
  } else {
    os::release_memory_special(result, large_allocation_size);

    // allocate another page within the recently allocated memory area which seems to be a good location. At least
    // we managed to get it once.
    const size_t expected_allocation_size = os::large_page_size();
    char* expected_location = result + os::large_page_size();
    char* actual_location = os::reserve_memory_special(expected_allocation_size, os::large_page_size(), expected_location, false);
    if (actual_location == NULL) {
      if (VerboseInternalVMTests) {
        gclog_or_tty->print("Failed to allocate any memory at "PTR_FORMAT" size "SIZE_FORMAT". Skipping remainder of test.",
                            expected_location, large_allocation_size);
      }
    } else {
      // release memory
      os::release_memory_special(actual_location, expected_allocation_size);
      // only now check, after releasing any memory to avoid any leaks.
      assert(actual_location == expected_location,
             err_msg("Failed to allocate memory at requested location "PTR_FORMAT" of size "SIZE_FORMAT", is "PTR_FORMAT" instead",
             expected_location, expected_allocation_size, actual_location));
    }
  }

  // restore globals
  UseLargePagesIndividualAllocation = old_use_large_pages_individual_allocation;
  UseNUMAInterleaving = old_use_numa_interleaving;
}
#endif // PRODUCT