--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/os_cpu/linux_ppc/vm/os_linux_ppc.cpp	Fri Aug 02 16:46:45 2013 +0200
@@ -0,0 +1,607 @@
+/*
+ * Copyright (c) 1997, 2013, Oracle and/or its affiliates. All rights reserved.
+ * Copyright 2012, 2013 SAP AG. 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 hat
+ * 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.
+ *
+ */
+
+// no precompiled headers
+#include "assembler_ppc.inline.hpp"
+#include "classfile/classLoader.hpp"
+#include "classfile/systemDictionary.hpp"
+#include "classfile/vmSymbols.hpp"
+#include "code/icBuffer.hpp"
+#include "code/vtableStubs.hpp"
+#include "interpreter/interpreter.hpp"
+#include "jvm_linux.h"
+#include "memory/allocation.inline.hpp"
+#include "mutex_linux.inline.hpp"
+#include "nativeInst_ppc.hpp"
+#include "os_share_linux.hpp"
+#include "prims/jniFastGetField.hpp"
+#include "prims/jvm.h"
+#include "prims/jvm_misc.hpp"
+#include "runtime/arguments.hpp"
+#include "runtime/extendedPC.hpp"
+#include "runtime/frame.inline.hpp"
+#include "runtime/interfaceSupport.hpp"
+#include "runtime/java.hpp"
+#include "runtime/javaCalls.hpp"
+#include "runtime/mutexLocker.hpp"
+#include "runtime/osThread.hpp"
+#include "runtime/sharedRuntime.hpp"
+#include "runtime/stubRoutines.hpp"
+#include "runtime/thread.inline.hpp"
+#include "runtime/timer.hpp"
+#include "utilities/events.hpp"
+#include "utilities/vmError.hpp"
+
+// put OS-includes here
+# include <sys/types.h>
+# include <sys/mman.h>
+# include <pthread.h>
+# include <signal.h>
+# include <errno.h>
+# include <dlfcn.h>
+# include <stdlib.h>
+# include <stdio.h>
+# include <unistd.h>
+# include <sys/resource.h>
+# include <pthread.h>
+# include <sys/stat.h>
+# include <sys/time.h>
+# include <sys/utsname.h>
+# include <sys/socket.h>
+# include <sys/wait.h>
+# include <pwd.h>
+# include <poll.h>
+# include <ucontext.h>
+
+
+address os::current_stack_pointer() {
+  intptr_t* csp;
+
+  // inline assembly `mr regno(csp), R1_SP':
+  __asm__ __volatile__ ("mr %0, 1":"=r"(csp):);
+
+  return (address) csp;
+}
+
+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;
+}
+
+void os::initialize_thread(Thread *thread) { }
+
+// Frame information (pc, sp, fp) retrieved via ucontext
+// always looks like a C-frame according to the frame
+// conventions in frame_ppc64.hpp.
+address os::Linux::ucontext_get_pc(ucontext_t * uc) {
+  // On powerpc64, ucontext_t is not selfcontained but contains
+  // a pointer to an optional substructure (mcontext_t.regs) containing the volatile
+  // registers - NIP, among others.
+  // This substructure may or may not be there depending where uc came from:
+  // - if uc was handed over as the argument to a sigaction handler, a pointer to the
+  //   substructure was provided by the kernel when calling the signal handler, and
+  //   regs->nip can be accessed.
+  // - if uc was filled by getcontext(), it is undefined - getcontext() does not fill
+  //   it because the volatile registers are not needed to make setcontext() work.
+  //   Hopefully it was zero'd out beforehand.
+  guarantee(uc->uc_mcontext.regs != NULL, "only use ucontext_get_pc in sigaction context");
+  return (address)uc->uc_mcontext.regs->nip;
+}
+
+intptr_t* os::Linux::ucontext_get_sp(ucontext_t * uc) {
+  return (intptr_t*)uc->uc_mcontext.regs->gpr[1/*REG_SP*/];
+}
+
+intptr_t* os::Linux::ucontext_get_fp(ucontext_t * uc) {
+  return NULL;
+}
+
+ExtendedPC os::fetch_frame_from_context(void* ucVoid,
+                    intptr_t** ret_sp, intptr_t** ret_fp) {
+
+  ExtendedPC  epc;
+  ucontext_t* uc = (ucontext_t*)ucVoid;
+
+  if (uc != NULL) {
+    epc = ExtendedPC(os::Linux::ucontext_get_pc(uc));
+    if (ret_sp) *ret_sp = os::Linux::ucontext_get_sp(uc);
+    if (ret_fp) *ret_fp = os::Linux::ucontext_get_fp(uc);
+  } else {
+    // construct empty ExtendedPC for return value checking
+    epc = ExtendedPC(NULL);
+    if (ret_sp) *ret_sp = (intptr_t *)NULL;
+    if (ret_fp) *ret_fp = (intptr_t *)NULL;
+  }
+
+  return epc;
+}
+
+frame os::fetch_frame_from_context(void* ucVoid) {
+  intptr_t* sp;
+  intptr_t* fp;
+  ExtendedPC epc = fetch_frame_from_context(ucVoid, &sp, &fp);
+  return frame(sp, epc.pc());
+}
+
+frame os::get_sender_for_C_frame(frame* fr) {
+  if (*fr->sp() == 0) {
+    // fr is the last C frame
+    return frame(NULL, NULL);
+  }
+  return frame(fr->sender_sp(), fr->sender_pc());
+}
+
+
+frame os::current_frame() {
+  intptr_t* csp = (intptr_t*) *((intptr_t*) os::current_stack_pointer());
+  // hack.
+  frame topframe(csp, (address)0x8);
+  // return sender of current topframe which hopefully has pc != NULL.
+  return os::get_sender_for_C_frame(&topframe);
+}
+
+// Utility functions
+
+extern "C" JNIEXPORT int
+JVM_handle_linux_signal(int sig,
+                        siginfo_t* info,
+                        void* ucVoid,
+                        int abort_if_unrecognized) {
+  ucontext_t* uc = (ucontext_t*) ucVoid;
+
+  Thread* t = ThreadLocalStorage::get_thread_slow();
+
+  SignalHandlerMark shm(t);
+
+  // Note: it's not uncommon that JNI code uses signal/sigset to install
+  // then restore certain signal handler (e.g. to temporarily block SIGPIPE,
+  // or have a SIGILL handler when detecting CPU type). When that happens,
+  // JVM_handle_linux_signal() might be invoked with junk info/ucVoid. To
+  // avoid unnecessary crash when libjsig is not preloaded, try handle signals
+  // that do not require siginfo/ucontext first.
+
+  if (sig == SIGPIPE) {
+    if (os::Linux::chained_handler(sig, info, ucVoid)) {
+      return true;
+    } else {
+      if (PrintMiscellaneous && (WizardMode || Verbose)) {
+        warning("Ignoring SIGPIPE - see bug 4229104");
+      }
+      return true;
+    }
+  }
+
+  JavaThread* thread = NULL;
+  VMThread* vmthread = NULL;
+  if (os::Linux::signal_handlers_are_installed) {
+    if (t != NULL) {
+      if(t->is_Java_thread()) {
+        thread = (JavaThread*)t;
+      } else if(t->is_VM_thread()) {
+        vmthread = (VMThread *)t;
+      }
+    }
+  }
+
+  // Moved SafeFetch32 handling outside thread!=NULL conditional block to make
+  // it work if no associated JavaThread object exists.
+  if (uc) {
+    address const pc = os::Linux::ucontext_get_pc(uc);
+    if (pc && StubRoutines::is_safefetch_fault(pc)) {
+      uc->uc_mcontext.regs->nip = (unsigned long)StubRoutines::continuation_for_safefetch_fault(pc);
+      return true;
+    }
+  }
+
+  // decide if this trap can be handled by a stub
+  address stub = NULL;
+  address pc   = NULL;
+
+  //%note os_trap_1
+  if (info != NULL && uc != NULL && thread != NULL) {
+    pc = (address) os::Linux::ucontext_get_pc(uc);
+
+    // Handle ALL stack overflow variations here
+    if (sig == SIGSEGV) {
+      // Si_addr may not be valid due to a bug in the linux-ppc64 kernel (see
+      // comment below). Use get_stack_bang_address instead of si_addr.
+      address addr = ((NativeInstruction*)pc)->get_stack_bang_address(uc);
+
+      // Check if fault address is within thread stack.
+      if (addr < thread->stack_base() &&
+          addr >= thread->stack_base() - thread->stack_size()) {
+        // stack overflow
+        if (thread->in_stack_yellow_zone(addr)) {
+          thread->disable_stack_yellow_zone();
+          if (thread->thread_state() == _thread_in_Java) {
+            // Throw a stack overflow exception.
+            // Guard pages will be reenabled while unwinding the stack.
+            stub = SharedRuntime::continuation_for_implicit_exception(thread, pc, SharedRuntime::STACK_OVERFLOW);
+          } else {
+            // Thread was in the vm or native code. Return and try to finish.
+            return 1;
+          }
+        } else if (thread->in_stack_red_zone(addr)) {
+          // Fatal red zone violation.  Disable the guard pages and fall through
+          // to handle_unexpected_exception way down below.
+          thread->disable_stack_red_zone();
+          tty->print_raw_cr("An irrecoverable stack overflow has occurred.");
+
+          // This is a likely cause, but hard to verify. Let's just print
+          // it as a hint.
+          tty->print_raw_cr("Please check if any of your loaded .so files has "
+                            "enabled executable stack (see man page execstack(8))");
+        } else {
+          // Accessing stack address below sp may cause SEGV if current
+          // thread has MAP_GROWSDOWN stack. This should only happen when
+          // current thread was created by user code with MAP_GROWSDOWN flag
+          // and then attached to VM. See notes in os_linux.cpp.
+          if (thread->osthread()->expanding_stack() == 0) {
+             thread->osthread()->set_expanding_stack();
+             if (os::Linux::manually_expand_stack(thread, addr)) {
+               thread->osthread()->clear_expanding_stack();
+               return 1;
+             }
+             thread->osthread()->clear_expanding_stack();
+          } else {
+             fatal("recursive segv. expanding stack.");
+          }
+        }
+      }
+    }
+
+    if (thread->thread_state() == _thread_in_Java) {
+      // Java thread running in Java code => find exception handler if any
+      // a fault inside compiled code, the interpreter, or a stub
+
+      // A VM-related SIGILL may only occur if we are not in the zero page.
+      // On AIX, we get a SIGILL if we jump to 0x0 or to somewhere else
+      // in the zero page, because it is filled with 0x0. We ignore
+      // explicit SIGILLs in the zero page.
+      if (sig == SIGILL && (pc < (address) 0x200)) {
+        if (TraceTraps)
+          tty->print_raw_cr("SIGILL happened inside zero page.");
+        goto report_and_die;
+      }
+
+      // Handle signal from NativeJump::patch_verified_entry().
+      if (( TrapBasedNotEntrantChecks && sig == SIGTRAP && nativeInstruction_at(pc)->is_sigtrap_zombie_not_entrant()) ||
+          (!TrapBasedNotEntrantChecks && sig == SIGILL  && nativeInstruction_at(pc)->is_sigill_zombie_not_entrant())) {
+        if (TraceTraps)
+          tty->print_cr("trap: zombie_not_entrant (%s)", (sig == SIGTRAP) ? "SIGTRAP" : "SIGILL");
+        stub = SharedRuntime::get_handle_wrong_method_stub();
+      }
+
+      else if (sig == SIGSEGV &&
+               // A linux-ppc64 kernel before 2.6.6 doesn't set si_addr on some segfaults
+               // in 64bit mode (cf. http://www.kernel.org/pub/linux/kernel/v2.6/ChangeLog-2.6.6),
+               // especially when we try to read from the safepoint polling page. So the check
+               //   (address)info->si_addr == os::get_standard_polling_page()
+               // doesn't work for us. We use:
+               ((NativeInstruction*)pc)->is_safepoint_poll()) {
+        if (TraceTraps)
+          tty->print_cr("trap: safepoint_poll at " INTPTR_FORMAT " (SIGSEGV)", pc);
+        stub = SharedRuntime::get_poll_stub(pc);
+      }
+
+      // SIGTRAP-based ic miss check in compiled code.
+      else if (sig == SIGTRAP && TrapBasedICMissChecks &&
+               nativeInstruction_at(pc)->is_sigtrap_ic_miss_check()) {
+        if (TraceTraps)
+          tty->print_cr("trap: ic_miss_check at " INTPTR_FORMAT " (SIGTRAP)", pc);
+        stub = SharedRuntime::get_ic_miss_stub();
+      }
+
+      // SIGTRAP-based implicit null check in compiled code.
+      else if (sig == SIGTRAP && TrapBasedNullChecks &&
+               nativeInstruction_at(pc)->is_sigtrap_null_check()) {
+        if (TraceTraps)
+          tty->print_cr("trap: null_check at " INTPTR_FORMAT " (SIGTRAP)", pc);
+        stub = SharedRuntime::continuation_for_implicit_exception(thread, pc, SharedRuntime::IMPLICIT_NULL);
+      }
+
+      // SIGSEGV-based implicit null check in compiled code.
+      else if (sig == SIGSEGV && ImplicitNullChecks &&
+               CodeCache::contains((void*) pc) &&
+               !MacroAssembler::needs_explicit_null_check((intptr_t) info->si_addr)) {
+        if (TraceTraps)
+          tty->print_cr("trap: null_check at " INTPTR_FORMAT " (SIGSEGV)", pc);
+        stub = SharedRuntime::continuation_for_implicit_exception(thread, pc, SharedRuntime::IMPLICIT_NULL);
+      }
+
+#ifdef COMPILER2
+      // SIGTRAP-based implicit range check in compiled code.
+      else if (sig == SIGTRAP && TrapBasedRangeChecks &&
+               nativeInstruction_at(pc)->is_sigtrap_range_check()) {
+        if (TraceTraps)
+          tty->print_cr("trap: range_check at " INTPTR_FORMAT " (SIGTRAP)", pc);
+        stub = SharedRuntime::continuation_for_implicit_exception(thread, pc, SharedRuntime::IMPLICIT_NULL);
+      }
+#endif
+      else if (sig == SIGBUS) {
+        // BugId 4454115: A read from a MappedByteBuffer can fault here if the
+        // underlying file has been truncated. Do not crash the VM in such a case.
+        CodeBlob* cb = CodeCache::find_blob_unsafe(pc);
+        nmethod* nm = (cb != NULL && cb->is_nmethod()) ? (nmethod*)cb : NULL;
+        if (nm != NULL && nm->has_unsafe_access()) {
+          // We don't really need a stub here! Just set the pending exeption and
+          // continue at the next instruction after the faulting read. Returning
+          // garbage from this read is ok.
+          thread->set_pending_unsafe_access_error();
+          uc->uc_mcontext.regs->nip = ((unsigned long)pc) + 4;
+          return true;
+        }
+      }
+    }
+
+    else { // thread->thread_state() != _thread_in_Java
+      if (sig == SIGILL && VM_Version::is_determine_features_test_running()) {
+        // SIGILL must be caused by VM_Version::determine_features().
+        *(int *)pc = 0; // patch instruction to 0 to indicate that it causes a SIGILL,
+                        // flushing of icache is not necessary.
+        stub = pc + 4;  // continue with next instruction.
+      }
+      else if (thread->thread_state() == _thread_in_vm &&
+               sig == SIGBUS && thread->doing_unsafe_access()) {
+        // We don't really need a stub here! Just set the pending exeption and
+        // continue at the next instruction after the faulting read. Returning
+        // garbage from this read is ok.
+        thread->set_pending_unsafe_access_error();
+        uc->uc_mcontext.regs->nip = ((unsigned long)pc) + 4;
+        return true;
+      }
+    }
+
+    // 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 we can just return to retry the write.
+    if ((sig == SIGSEGV) &&
+        // Si_addr may not be valid due to a bug in the linux-ppc64 kernel (see comment above).
+        // Use is_memory_serialization instead of si_addr.
+        ((NativeInstruction*)pc)->is_memory_serialization(thread, ucVoid)) {
+      // Synchronization problem in the pseudo memory barrier code (bug id 6546278)
+      // Block current thread until the memory serialize page permission restored.
+      os::block_on_serialize_page_trap();
+      return true;
+    }
+  }
+
+  if (stub != NULL) {
+    // Save all thread context in case we need to restore it.
+    if (thread != NULL) thread->set_saved_exception_pc(pc);
+    uc->uc_mcontext.regs->nip = (unsigned long)stub;
+    return true;
+  }
+
+  // signal-chaining
+  if (os::Linux::chained_handler(sig, info, ucVoid)) {
+    return true;
+  }
+
+  if (!abort_if_unrecognized) {
+    // caller wants another chance, so give it to him
+    return false;
+  }
+
+  if (pc == NULL && uc != NULL) {
+    pc = os::Linux::ucontext_get_pc(uc);
+  }
+
+report_and_die:
+  // unmask current signal
+  sigset_t newset;
+  sigemptyset(&newset);
+  sigaddset(&newset, sig);
+  sigprocmask(SIG_UNBLOCK, &newset, NULL);
+
+  VMError err(t, sig, pc, info, ucVoid);
+  err.report_and_die();
+
+  ShouldNotReachHere();
+  return false;
+}
+
+void os::Linux::init_thread_fpu_state(void) {
+  // Disable FP exceptions.
+  __asm__ __volatile__ ("mtfsfi 6,0");
+}
+
+int os::Linux::get_fpu_control_word(void) {
+  // x86 has problems with FPU precision after pthread_cond_timedwait().
+  // nothing to do on ppc64.
+  return 0;
+}
+
+void os::Linux::set_fpu_control_word(int fpu_control) {
+  // x86 has problems with FPU precision after pthread_cond_timedwait().
+  // nothing to do on ppc64.
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// thread stack
+
+size_t os::Linux::min_stack_allowed = 768*K;
+
+bool os::Linux::supports_variable_stack_size() { return true; }
+
+// return default stack size for thr_type
+size_t os::Linux::default_stack_size(os::ThreadType thr_type) {
+  // default stack size (compiler thread needs larger stack)
+  // Notice that the setting for compiler threads here have no impact
+  // because of the strange 'fallback logic' in os::create_thread().
+  // Better set CompilerThreadStackSize in globals_<os_cpu>.hpp if you want to
+  // specify a different stack size for compiler threads!
+  size_t s = (thr_type == os::compiler_thread ? 4 * M : 1024 * K);
+  return s;
+}
+
+size_t os::Linux::default_guard_size(os::ThreadType thr_type) {
+  return 2 * page_size();
+}
+
+// Java thread:
+//
+//   Low memory addresses
+//    +------------------------+
+//    |                        |\  JavaThread created by VM does not have glibc
+//    |    glibc guard page    | - guard, attached Java thread usually has
+//    |                        |/  1 page glibc guard.
+// P1 +------------------------+ Thread::stack_base() - Thread::stack_size()
+//    |                        |\
+//    |  HotSpot Guard Pages   | - red and yellow pages
+//    |                        |/
+//    +------------------------+ JavaThread::stack_yellow_zone_base()
+//    |                        |\
+//    |      Normal Stack      | -
+//    |                        |/
+// P2 +------------------------+ Thread::stack_base()
+//
+// Non-Java thread:
+//
+//   Low memory addresses
+//    +------------------------+
+//    |                        |\
+//    |  glibc guard page      | - usually 1 page
+//    |                        |/
+// P1 +------------------------+ Thread::stack_base() - Thread::stack_size()
+//    |                        |\
+//    |      Normal Stack      | -
+//    |                        |/
+// P2 +------------------------+ Thread::stack_base()
+//
+// ** P1 (aka bottom) and size ( P2 = P1 - size) are the address and stack size returned from
+//    pthread_attr_getstack()
+
+static void current_stack_region(address * bottom, size_t * size) {
+  if (os::Linux::is_initial_thread()) {
+     // initial thread needs special handling because pthread_getattr_np()
+     // may return bogus value.
+    *bottom = os::Linux::initial_thread_stack_bottom();
+    *size   = os::Linux::initial_thread_stack_size();
+  } else {
+    pthread_attr_t attr;
+
+    int rslt = pthread_getattr_np(pthread_self(), &attr);
+
+    // JVM needs to know exact stack location, abort if it fails
+    if (rslt != 0) {
+      if (rslt == ENOMEM) {
+        vm_exit_out_of_memory(0, OOM_MMAP_ERROR, "pthread_getattr_np");
+      } else {
+        fatal(err_msg("pthread_getattr_np failed with errno = %d", rslt));
+      }
+    }
+
+    if (pthread_attr_getstack(&attr, (void **)bottom, size) != 0) {
+      fatal("Can not locate current stack attributes!");
+    }
+
+    pthread_attr_destroy(&attr);
+
+  }
+  assert(os::current_stack_pointer() >= *bottom &&
+         os::current_stack_pointer() < *bottom + *size, "just checking");
+}
+
+address os::current_stack_base() {
+  address bottom;
+  size_t size;
+  current_stack_region(&bottom, &size);
+  return (bottom + size);
+}
+
+size_t os::current_stack_size() {
+  // stack size includes normal stack and HotSpot guard pages
+  address bottom;
+  size_t size;
+  current_stack_region(&bottom, &size);
+  return size;
+}
+
+/////////////////////////////////////////////////////////////////////////////
+// helper functions for fatal error handler
+
+void os::print_context(outputStream *st, void *context) {
+  if (context == NULL) return;
+
+  ucontext_t* uc = (ucontext_t*)context;
+
+  st->print_cr("Registers:");
+  st->print("pc =" INTPTR_FORMAT "  ", uc->uc_mcontext.regs->nip);
+  st->print("lr =" INTPTR_FORMAT "  ", uc->uc_mcontext.regs->link);
+  st->print("ctr=" INTPTR_FORMAT "  ", uc->uc_mcontext.regs->ctr);
+  st->cr();
+  for (int i = 0; i < 32; i++) {
+    st->print("r%-2d=" INTPTR_FORMAT "  ", i, uc->uc_mcontext.regs->gpr[i]);
+    if (i % 3 == 2) st->cr();
+  }
+  st->cr();
+  st->cr();
+
+  intptr_t *sp = (intptr_t *)os::Linux::ucontext_get_sp(uc);
+  st->print_cr("Top of Stack: (sp=" PTR_FORMAT ")", sp);
+  print_hex_dump(st, (address)sp, (address)(sp + 128), sizeof(intptr_t));
+  st->cr();
+
+  // Note: it may be unsafe to inspect memory near pc. For example, pc may
+  // point to garbage if entry point in an nmethod is corrupted. Leave
+  // this at the end, and hope for the best.
+  address pc = os::Linux::ucontext_get_pc(uc);
+  st->print_cr("Instructions: (pc=" PTR_FORMAT ")", pc);
+  print_hex_dump(st, pc - 64, pc + 64, /*instrsize=*/4);
+  st->cr();
+}
+
+void os::print_register_info(outputStream *st, void *context) {
+  if (context == NULL) return;
+
+  ucontext_t *uc = (ucontext_t*)context;
+
+  st->print_cr("Register to memory mapping:");
+  st->cr();
+
+  // this is only for the "general purpose" registers
+  for (int i = 0; i < 32; i++) {
+    st->print("r%-2d=", i);
+    print_location(st, uc->uc_mcontext.regs->gpr[i]);
+  }
+  st->cr();
+}
+
+extern "C" {
+  int SpinPause() {
+    return 0;
+  }
+}
+
+#ifndef PRODUCT
+void os::verify_stack_alignment() {
+  assert(((intptr_t)os::current_stack_pointer() & (StackAlignmentInBytes-1)) == 0, "incorrect stack alignment");
+}
+#endif