Mercurial > jdk8-mips64-public > hotspot / file revision

 /*

  * Copyright (c) 1997, 2018, 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 2000 or XP to use IsDebuggerPresent

 #define _WIN32_WINNT 0x500

 // 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 "prims/jniFastGetField.hpp"

 #include "prims/jvm.h"

 #include "prims/jvm_misc.hpp"

 #include "runtime/arguments.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 "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

 #else

   #ifdef _M_AMD64

     #define __CPU__ amd64

   #else

     #define __CPU__ i486

   #endif

 #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;

 }

 #ifndef _WIN64

 // previous UnhandledExceptionFilter, if there is one

 static LPTOP_LEVEL_EXCEPTION_FILTER prev_uef_handler = NULL;

 LONG WINAPI Handle_FLT_Exception(struct _EXCEPTION_POINTERS* exceptionInfo);

 #endif

 void os::init_system_properties_values() {

   /* sysclasspath, java_home, dll_dir */

   {

       char *home_path;

       char *dll_path;

       char *pslash;

       char *bin = "\\bin";

       char home_dir[MAX_PATH];

       if (!getenv("_ALT_JAVA_HOME_DIR", home_dir, MAX_PATH)) {

           os::jvm_path(home_dir, sizeof(home_dir));

           // Found the full path to jvm.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);

     }

   }

   // Install a win32 structured exception handler around every thread created

   // by VM, so VM can genrate error dump when an exception occurred in non-

   // Java thread (e.g. VM thread).

   __try {

      thread->run();

   } __except(topLevelExceptionFilter(

              (_EXCEPTION_POINTERS*)_exception_info())) {

       // Nothing to do.

   }

   // One less thread is executing

   // When the VMThread gets here, the main thread may have already exited

   // which frees the CodeHeap containing the Atomic::add code

   if (thread != VMThread::vm_thread() && VMThread::vm_thread() != NULL) {

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

   }

   return 0;

 }

 static OSThread* create_os_thread(Thread* thread, HANDLE thread_handle, int thread_id) {

   // Allocate the OSThread object

   OSThread* osthread = new OSThread(NULL, NULL);

   if (osthread == NULL) return NULL;

   // Initialize support for Java interrupts

   HANDLE interrupt_event = CreateEvent(NULL, true, false, NULL);

   if (interrupt_event == NULL) {

     delete osthread;

     return NULL;

   }

   osthread->set_interrupt_event(interrupt_event);

   // Store info on the Win32 thread into the OSThread

   osthread->set_thread_handle(thread_handle);

   osthread->set_thread_id(thread_id);

   if (UseNUMA) {

     int lgrp_id = os::numa_get_group_id();

     if (lgrp_id != -1) {

       thread->set_lgrp_id(lgrp_id);

     }

   }

   // Initial thread state is INITIALIZED, not SUSPENDED

   osthread->set_state(INITIALIZED);

   return osthread;

 }

 bool os::create_attached_thread(JavaThread* thread) {

 #ifdef ASSERT

   thread->verify_not_published();

 #endif

   HANDLE thread_h;

   if (!DuplicateHandle(main_process, GetCurrentThread(), GetCurrentProcess(),

                        &thread_h, THREAD_ALL_ACCESS, false, 0)) {

     fatal("DuplicateHandle failed\n");

   }

   OSThread* osthread = create_os_thread(thread, thread_h,

                                         (int)current_thread_id());

   if (osthread == NULL) {

      return false;

   }

   // Initial thread state is RUNNABLE

   osthread->set_state(RUNNABLE);

   thread->set_osthread(osthread);

   return true;

 }

 bool os::create_main_thread(JavaThread* thread) {

 #ifdef ASSERT

   thread->verify_not_published();

 #endif

   if (_starting_thread == NULL) {

     _starting_thread = create_os_thread(thread, main_thread, main_thread_id);

      if (_starting_thread == NULL) {

         return false;

      }

   }

   // The primordial thread is runnable from the start)

   _starting_thread->set_state(RUNNABLE);

   thread->set_osthread(_starting_thread);

   return true;

 }

 // Allocate and initialize a new OSThread

 bool os::create_thread(Thread* thread, ThreadType thr_type, size_t stack_size) {

   unsigned thread_id;

   // Allocate the OSThread object

   OSThread* osthread = new OSThread(NULL, NULL);

   if (osthread == NULL) {

     return false;

   }

   // Initialize support for Java interrupts

   HANDLE interrupt_event = CreateEvent(NULL, true, false, NULL);

   if (interrupt_event == NULL) {

     delete osthread;

     return NULL;

   }

   osthread->set_interrupt_event(interrupt_event);

   osthread->set_interrupted(false);

   thread->set_osthread(osthread);

   if (stack_size == 0) {

     switch (thr_type) {

     case os::java_thread:

       // Java threads use ThreadStackSize which default value can be changed with the flag -Xss

       if (JavaThread::stack_size_at_create() > 0)

         stack_size = JavaThread::stack_size_at_create();

       break;

     case os::compiler_thread:

       if (CompilerThreadStackSize > 0) {

         stack_size = (size_t)(CompilerThreadStackSize * K);

         break;

       } // else fall through:

         // use VMThreadStackSize if CompilerThreadStackSize is not defined

     case os::vm_thread:

     case os::pgc_thread:

     case os::cgc_thread:

     case os::watcher_thread:

       if (VMThreadStackSize > 0) stack_size = (size_t)(VMThreadStackSize * K);

       break;

     }

   }

   // Create the Win32 thread

   //

   // Contrary to what MSDN document says, "stack_size" in _beginthreadex()

   // does not specify stack size. Instead, it specifies the size of

   // initially committed space. The stack size is determined by

   // PE header in the executable. If the committed "stack_size" is larger

   // than default value in the PE header, the stack is rounded up to the

   // nearest multiple of 1MB. For example if the launcher has default

   // stack size of 320k, specifying any size less than 320k does not

   // affect the actual stack size at all, it only affects the initial

   // commitment. On the other hand, specifying 'stack_size' larger than

   // default value may cause significant increase in memory usage, because

   // not only the stack space will be rounded up to MB, but also the

   // entire space is committed upfront.

   //

   // Finally Windows XP added a new flag 'STACK_SIZE_PARAM_IS_A_RESERVATION'

   // for CreateThread() that can treat 'stack_size' as stack size. However we

   // are not supposed to call CreateThread() directly according to MSDN

   // document because JVM uses C runtime library. The good news is that the

   // flag appears to work with _beginthredex() as well.

 #ifndef STACK_SIZE_PARAM_IS_A_RESERVATION

 #define STACK_SIZE_PARAM_IS_A_RESERVATION  (0x10000)

 #endif

   HANDLE thread_handle =

     (HANDLE)_beginthreadex(NULL,

                            (unsigned)stack_size,

                            (unsigned (__stdcall *)(void*)) java_start,

                            thread,

                            CREATE_SUSPENDED | STACK_SIZE_PARAM_IS_A_RESERVATION,

                            &thread_id);

   if (thread_handle == NULL) {

     // perhaps STACK_SIZE_PARAM_IS_A_RESERVATION is not supported, try again

     // without the flag.

     thread_handle =

     (HANDLE)_beginthreadex(NULL,

                            (unsigned)stack_size,

                            (unsigned (__stdcall *)(void*)) java_start,

                            thread,

                            CREATE_SUSPENDED,

                            &thread_id);

   }

   if (thread_handle == NULL) {

     // Need to clean up stuff we've allocated so far

     CloseHandle(osthread->interrupt_event());

     thread->set_osthread(NULL);

     delete osthread;

     return NULL;

   }

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

   // Store info on the Win32 thread into the OSThread

   osthread->set_thread_handle(thread_handle);

   osthread->set_thread_id(thread_id);

   // Initial thread state is INITIALIZED, not SUSPENDED

   osthread->set_state(INITIALIZED);

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

   return true;

 }

 // Free Win32 resources related to the OSThread

 void os::free_thread(OSThread* osthread) {

   assert(osthread != NULL, "osthread not set");

   CloseHandle(osthread->thread_handle());

   CloseHandle(osthread->interrupt_event());

   delete osthread;

 }

 static int    has_performance_count = 0;

 static jlong first_filetime;

 static jlong initial_performance_count;

 static jlong performance_frequency;

 jlong as_long(LARGE_INTEGER x) {

   jlong result = 0; // initialization to avoid warning

   set_high(&result, x.HighPart);

   set_low(&result,  x.LowPart);

   return result;

 }

 jlong os::elapsed_counter() {

   LARGE_INTEGER count;

   if (has_performance_count) {

     QueryPerformanceCounter(&count);

     return as_long(count) - initial_performance_count;

   } else {

     FILETIME wt;

     GetSystemTimeAsFileTime(&wt);

     return (jlong_from(wt.dwHighDateTime, wt.dwLowDateTime) - first_filetime);

   }

 }

 jlong os::elapsed_frequency() {

   if (has_performance_count) {

     return performance_frequency;

   } else {

    // the FILETIME time is the number of 100-nanosecond intervals since January 1,1601.

    return 10000000;

   }

 }

 julong os::available_memory() {

   return win32::available_memory();

 }

 julong os::win32::available_memory() {

   // 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() {

   // User has overridden the number of active processors

   if (ActiveProcessorCount > 0) {

     if (PrintActiveCpus) {

       tty->print_cr("active_processor_count: "

                     "active processor count set by user : %d",

                      ActiveProcessorCount);

     }

     return ActiveProcessorCount;

   }

   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;

 }

 static void initialize_performance_counter() {

   LARGE_INTEGER count;

   if (QueryPerformanceFrequency(&count)) {

     has_performance_count = 1;

     performance_frequency = as_long(count);

     QueryPerformanceCounter(&count);

     initial_performance_count = as_long(count);

   } else {

     has_performance_count = 0;

     FILETIME wt;

     GetSystemTimeAsFileTime(&wt);

     first_filetime = jlong_from(wt.dwHighDateTime, wt.dwLowDateTime);

   }

 }

 double os::elapsedTime() {

   return (double) elapsed_counter() / (double) elapsed_frequency();

 }

 // Windows format:

 //   The FILETIME structure is a 64-bit value representing the number of 100-nanosecond intervals since January 1, 1601.

 // Java format:

 //   Java standards require the number of milliseconds since 1/1/1970

 // Constant offset - calculated using offset()

 static jlong  _offset   = 116444736000000000;

 // Fake time counter for reproducible results when debugging

 static jlong  fake_time = 0;

 #ifdef ASSERT

 // Just to be safe, recalculate the offset in debug mode

 static jlong _calculated_offset = 0;

 static int   _has_calculated_offset = 0;

 jlong offset() {

   if (_has_calculated_offset) return _calculated_offset;

   SYSTEMTIME java_origin;

   java_origin.wYear          = 1970;

   java_origin.wMonth         = 1;

   java_origin.wDayOfWeek     = 0; // ignored

   java_origin.wDay           = 1;

   java_origin.wHour          = 0;

   java_origin.wMinute        = 0;

   java_origin.wSecond        = 0;

   java_origin.wMilliseconds  = 0;

   FILETIME jot;

   if (!SystemTimeToFileTime(&java_origin, &jot)) {

     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 (!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 (!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

   ::exit(1);

 }

 // Die immediately, no exit hook, no abort hook, no cleanup.

 void os::die() {

   _exit(-1);

 }

 // Directory routines copied from src/win32/native/java/io/dirent_md.c

 //  * dirent_md.c       1.15 00/02/02

 //

 // The declarations for DIR and struct dirent are in jvm_win32.h.

 /* Caller must have already run dirname through JVM_NativePath, which removes

    duplicate slashes and converts all instances of '/' into '\\'. */

 DIR *

 os::opendir(const char *dirname)

 {

     assert(dirname != NULL, "just checking");   // hotspot change

     DIR *dirp = (DIR *)malloc(sizeof(DIR), 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

 // Enumerate all modules for a given process ID

 //

 // Notice that Windows 95/98/Me and Windows NT/2000/XP have

 // different API for doing this. We use PSAPI.DLL on NT based

 // Windows and ToolHelp on 95/98/Me.

 // Callback function that is called by enumerate_modules() on

 // every DLL module.

 // Input parameters:

 //    int       pid,

 //    char*     module_file_name,

 //    address   module_base_addr,

 //    unsigned  module_size,

 //    void*     param

 typedef int (*EnumModulesCallbackFunc)(int, char *, address, unsigned, void *);

 // enumerate_modules for Windows NT, using PSAPI

 static int _enumerate_modules_winnt( int pid, EnumModulesCallbackFunc func, void * param)

 {

   HANDLE   hProcess ;

 # define MAX_NUM_MODULES 128

   HMODULE     modules[MAX_NUM_MODULES];

   static char filename[ MAX_PATH ];

   int         result = 0;

   if (!os::PSApiDll::PSApiAvailable()) {

     return 0;

   }

   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 = func(pid, filename, (address)modinfo.lpBaseOfDll,

                   modinfo.SizeOfImage, param);

     if (result) break;

   }

   CloseHandle( hProcess ) ;

   return result;

 }

 // enumerate_modules for Windows 95/98/ME, using TOOLHELP

 static int _enumerate_modules_windows( int pid, EnumModulesCallbackFunc func, void *param)

 {

   HANDLE                hSnapShot ;

   static MODULEENTRY32  modentry ;

   int                   result = 0;

   if (!os::Kernel32Dll::HelpToolsAvailable()) {

     return 0;

   }

   // Get a handle to a Toolhelp snapshot of the system

   hSnapShot = os::Kernel32Dll::CreateToolhelp32Snapshot(TH32CS_SNAPMODULE, pid ) ;

   if( hSnapShot == INVALID_HANDLE_VALUE ) {

       return FALSE ;

   }

   // iterate through all modules

   modentry.dwSize = sizeof(MODULEENTRY32) ;

   bool not_done = os::Kernel32Dll::Module32First( hSnapShot, &modentry ) != 0;

   while( not_done ) {

     // invoke the callback

     result=func(pid, modentry.szExePath, (address)modentry.modBaseAddr,

                 modentry.modBaseSize, param);

     if (result) break;

     modentry.dwSize = sizeof(MODULEENTRY32) ;

     not_done = os::Kernel32Dll::Module32Next( hSnapShot, &modentry ) != 0;

   }

   CloseHandle(hSnapShot);

   return result;

 }

 int enumerate_modules( int pid, EnumModulesCallbackFunc func, void * param )

 {

   // Get current process ID if caller doesn't provide it.

   if (!pid) pid = os::current_process_id();

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

   else                    return _enumerate_modules_windows(pid, func, param);

 }

 struct _modinfo {

    address addr;

    char*   full_path;   // point to a char buffer

    int     buflen;      // size of the buffer

    address base_addr;

 };

 static int _locate_module_by_addr(int pid, char * mod_fname, address base_addr,

                                   unsigned size, void * param) {

    struct _modinfo *pmod = (struct _modinfo *)param;

    if (!pmod) return -1;

    if (base_addr     <= pmod->addr &&

        base_addr+size > pmod->addr) {

      // if a buffer is provided, copy path name to the buffer

      if (pmod->full_path) {

        jio_snprintf(pmod->full_path, pmod->buflen, "%s", mod_fname);

      }

      pmod->base_addr = base_addr;

      return 1;

    }

    return 0;

 }

 bool os::dll_address_to_library_name(address addr, char* buf,

                                      int buflen, int* offset) {

   // 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;

   int pid = os::current_process_id();

   if (enumerate_modules(pid, _locate_module_by_addr, (void *)&mi)) {

     // buf already contains path name

     if (offset) *offset = addr - mi.base_addr;

     return true;

   }

   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(int pid, char* mod_fname, address base_addr,

                     unsigned size, void * param) {

    if (!param) return -1;

    if (base_addr     <= (address)_locate_jvm_dll &&

        base_addr+size > (address)_locate_jvm_dll) {

          ((address*)param)[0] = base_addr;

          ((address*)param)[1] = base_addr + size;

          return 1;

    }

    return 0;

 }

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

 // check if addr is inside jvm.dll

 bool os::address_is_in_vm(address addr) {

   if (!vm_lib_location[0] || !vm_lib_location[1]) {

     int pid = os::current_process_id();

     if (!enumerate_modules(pid, _locate_jvm_dll, (void *)vm_lib_location)) {

       assert(false, "Can't find jvm module.");

       return false;

     }

   }

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

 }

 // print module info; param is outputStream*

 static int _print_module(int pid, char* fname, address base,

                          unsigned size, void* param) {

    if (!param) return -1;

    outputStream* st = (outputStream*)param;

    address end_addr = base + size;

    st->print(PTR_FORMAT " - " PTR_FORMAT " \t%s\n", base, end_addr, fname);

    return 0;

 }

 // Loads .dll/.so and

 // in case of error it checks if .dll/.so was built for the

 // same architecture as Hotspot is running on

 void * os::dll_load(const char *name, char *ebuf, int ebuflen)

 {

   void * result = LoadLibrary(name);

   if (result != NULL)

   {

     return result;

   }

   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 file_descriptor=::open(name, O_RDONLY | O_BINARY, 0);

   if (file_descriptor<0)

   {

     return NULL;

   }

   uint32_t signature_offset;

   uint16_t lib_arch=0;

   bool failed_to_get_lib_arch=

   (

     //Go to position 3c in the dll

     (os::seek_to_file_offset(file_descriptor,IMAGE_FILE_PTR_TO_SIGNATURE)<0)

     ||

     // Read loacation of signature

     (sizeof(signature_offset)!=

       (os::read(file_descriptor, (void*)&signature_offset,sizeof(signature_offset))))

     ||

     //Go to COFF File Header in dll

     //that is located after"signature" (4 bytes long)

     (os::seek_to_file_offset(file_descriptor,

       signature_offset+IMAGE_FILE_SIGNATURE_LENGTH)<0)

     ||

     //Read field that contains code of architecture

     // that dll was build for

     (sizeof(lib_arch)!=

       (os::read(file_descriptor, (void*)&lib_arch,sizeof(lib_arch))))

   );

   ::close(file_descriptor);

   if (failed_to_get_lib_arch)

   {

     // file i/o error - report 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 runing architecture code in arch_array");

   // If the architure 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) {

    int pid = os::current_process_id();

    st->print_cr("Dynamic libraries:");

    enumerate_modules(pid, _print_module, (void *)st);

 }

 void os::print_os_info_brief(outputStream* st) {

   os::print_os_info(st);

 }

 void os::print_os_info(outputStream* st) {

   st->print("OS:");

   os::win32::print_windows_version(st);

 }

 void os::win32::print_windows_version(outputStream* st) {

   OSVERSIONINFOEX osvi;

   VS_FIXEDFILEINFO *file_info;

   TCHAR kernel32_path[MAX_PATH];

   UINT len, ret;

   // Use the GetVersionEx information to see if we're on a server or

   // workstation edition of Windows. Starting with Windows 8.1 we can't

   // trust the OS version information returned by this API.

   ZeroMemory(&osvi, sizeof(OSVERSIONINFOEX));

   osvi.dwOSVersionInfoSize = sizeof(OSVERSIONINFOEX);

   if (!GetVersionEx((OSVERSIONINFO *)&osvi)) {

     st->print_cr("Call to GetVersionEx failed");

     return;

   }

   bool is_workstation = (osvi.wProductType == VER_NT_WORKSTATION);

   // Get the full path to \Windows\System32\kernel32.dll and use that for

   // determining what version of Windows we're running on.

   len = MAX_PATH - (UINT)strlen("\\kernel32.dll") - 1;

   ret = GetSystemDirectory(kernel32_path, len);

   if (ret == 0 || ret > len) {

     st->print_cr("Call to GetSystemDirectory failed");

     return;

   }

   strncat(kernel32_path, "\\kernel32.dll", MAX_PATH - ret);

   DWORD version_size = GetFileVersionInfoSize(kernel32_path, NULL);

   if (version_size == 0) {

     st->print_cr("Call to GetFileVersionInfoSize failed");

     return;

   }

   LPTSTR version_info = (LPTSTR)os::malloc(version_size, mtInternal);

   if (version_info == NULL) {

     st->print_cr("Failed to allocate version_info");

     return;

   }

   if (!GetFileVersionInfo(kernel32_path, NULL, version_size, version_info)) {

     os::free(version_info);

     st->print_cr("Call to GetFileVersionInfo failed");

     return;

   }

   if (!VerQueryValue(version_info, TEXT("\\"), (LPVOID*)&file_info, &len)) {

     os::free(version_info);

     st->print_cr("Call to VerQueryValue failed");

     return;

   }

   int major_version = HIWORD(file_info->dwProductVersionMS);

   int minor_version = LOWORD(file_info->dwProductVersionMS);

   int build_number = HIWORD(file_info->dwProductVersionLS);

   int build_minor = LOWORD(file_info->dwProductVersionLS);

   int os_vers = major_version * 1000 + minor_version;

   os::free(version_info);

   st->print(" Windows ");

   switch (os_vers) {

   case 6000:

     if (is_workstation) {

       st->print("Vista");

     } else {

       st->print("Server 2008");

     }

     break;

   case 6001:

     if (is_workstation) {

       st->print("7");

     } else {

       st->print("Server 2008 R2");

     }

     break;

   case 6002:

     if (is_workstation) {

       st->print("8");

     } else {

       st->print("Server 2012");

     }

     break;

   case 6003:

     if (is_workstation) {

       st->print("8.1");

     } else {

       st->print("Server 2012 R2");

     }

     break;

   case 6004:

     if (is_workstation) {

       st->print("10");

     } else {

       st->print("Server 2016");

     }

     break;

   default:

     // Unrecognized windows, print out its major and minor versions

     st->print("%d.%d", major_version, minor_version);

     break;

   }

   // Retrieve SYSTEM_INFO from GetNativeSystemInfo call so that we could

   // find out whether we are running on 64 bit processor or not

   SYSTEM_INFO si;

   ZeroMemory(&si, sizeof(SYSTEM_INFO));

   os::Kernel32Dll::GetNativeSystemInfo(&si);

   if (si.wProcessorArchitecture == PROCESSOR_ARCHITECTURE_AMD64) {

     st->print(" , 64 bit");

   }

   st->print(" Build %d", build_number);

   st->print(" (%d.%d.%d.%d)", major_version, minor_version, build_number, build_minor);

   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::created_by_gamma_launcher()) {

      // Support for the gamma launcher. Check for an

      // JAVA_HOME environment variable

      // and fix up the path so it looks like

      // libjvm.so is installed there (append a fake suffix

      // hotspot/libjvm.so).

      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!");

 #else

   #ifdef _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

 #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

 // 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

 #define def_excpt(val) { #val, (val) }

 static const struct { char* name; uint number; } 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

 };

 const char* os::exception_name(int exception_code, char *buf, size_t size) {

   uint code = static_cast<uint>(exception_code);

   for (uint i = 0; i < ARRAY_SIZE(exceptlabels); ++i) {

     if (exceptlabels[i].number == 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");

 #else

   #ifdef  _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 = (DWORD64)pc + 2;        // idiv reg, reg  is 2 bytes

   ctx->Rax = (DWORD64)min_jint;      // result

   ctx->Rdx = (DWORD64)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

 #endif

   return EXCEPTION_CONTINUE_EXECUTION;

 }

 #ifndef  _WIN64

 //-----------------------------------------------------------------------------

 LONG WINAPI Handle_FLT_Exception(struct _EXCEPTION_POINTERS* exceptionInfo) {

   // handle exception caused by native method modifying control word

   PCONTEXT ctx = exceptionInfo->ContextRecord;

   DWORD exception_code = exceptionInfo->ExceptionRecord->ExceptionCode;

   switch (exception_code) {

     case EXCEPTION_FLT_DENORMAL_OPERAND:

     case EXCEPTION_FLT_DIVIDE_BY_ZERO:

     case EXCEPTION_FLT_INEXACT_RESULT:

     case EXCEPTION_FLT_INVALID_OPERATION:

     case EXCEPTION_FLT_OVERFLOW:

     case EXCEPTION_FLT_STACK_CHECK:

     case EXCEPTION_FLT_UNDERFLOW:

       jint fp_control_word = (* (jint*) StubRoutines::addr_fpu_cntrl_wrd_std());

       if (fp_control_word != ctx->FloatSave.ControlWord) {

         // Restore FPCW and mask out FLT exceptions

         ctx->FloatSave.ControlWord = fp_control_word | 0xffffffc0;

         // Mask out pending FLT exceptions

         ctx->FloatSave.StatusWord &=  0xffffff00;

         return EXCEPTION_CONTINUE_EXECUTION;

       }

   }

   if (prev_uef_handler != NULL) {

     // We didn't handle this exception so pass it to the previous

     // UnhandledExceptionFilter.

     return (prev_uef_handler)(exceptionInfo);

   }

   return EXCEPTION_CONTINUE_SEARCH;

 }

 #else //_WIN64

 /*

   On Windows, the mxcsr control bits are non-volatile across calls

   See also CR 6192333

   If EXCEPTION_FLT_* happened after some native method modified

   mxcsr - it is not a jvm fault.

   However should we decide to restore of mxcsr after a faulty

   native method we can uncomment following code

       jint MxCsr = INITIAL_MXCSR;

         // we can't use StubRoutines::addr_mxcsr_std()

         // because in Win64 mxcsr is not saved there

       if (MxCsr != ctx->MxCsr) {

         ctx->MxCsr = MxCsr;

         return EXCEPTION_CONTINUE_EXECUTION;

       }

 */

 #endif // _WIN64

 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));

 #else

   #ifdef _M_AMD64

   address pc = (address) exceptionInfo->ContextRecord->Rip;

   #else

   address pc = (address) exceptionInfo->ContextRecord->Eip;

   #endif

 #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) {