jdk8-mips64-public/hotspot: src/cpu/x86/vm/stubGenerator_x86

src/cpu/x86/vm/stubGenerator_x86_32.cpp@dca455dea3a7 (annotated)

src/cpu/x86/vm/stubGenerator_x86_32.cpp

Tue, 20 Dec 2011 12:33:05 +0100

author: bdelsart
date: Tue, 20 Dec 2011 12:33:05 +0100
changeset 3372: dca455dea3a7
parent 3156: f08d439fab8c
child 3400: 22cee0ee8927
permissions: -rw-r--r--

7116216: StackOverflow GC crash
Summary: GC crash for explicit stack overflow checks after a C2I transition.
Reviewed-by: coleenp, never
Contributed-by: yang02.wang@sap.com, bertrand.delsart@oracle.com

 /*
  * Copyright (c) 1999, 2011, 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.
  *
  */
 #include "precompiled.hpp"
 #include "asm/assembler.hpp"
 #include "assembler_x86.inline.hpp"
 #include "interpreter/interpreter.hpp"
 #include "nativeInst_x86.hpp"
 #include "oops/instanceOop.hpp"
 #include "oops/methodOop.hpp"
 #include "oops/objArrayKlass.hpp"
 #include "oops/oop.inline.hpp"
 #include "prims/methodHandles.hpp"
 #include "runtime/frame.inline.hpp"
 #include "runtime/handles.inline.hpp"
 #include "runtime/sharedRuntime.hpp"
 #include "runtime/stubCodeGenerator.hpp"
 #include "runtime/stubRoutines.hpp"
 #include "utilities/top.hpp"
 #ifdef TARGET_OS_FAMILY_linux
 # include "thread_linux.inline.hpp"
 #endif
 #ifdef TARGET_OS_FAMILY_solaris
 # include "thread_solaris.inline.hpp"
 #endif
 #ifdef TARGET_OS_FAMILY_windows
 # include "thread_windows.inline.hpp"
 #endif
 #ifdef TARGET_OS_FAMILY_bsd
 # include "thread_bsd.inline.hpp"
 #endif
 #ifdef COMPILER2
 #include "opto/runtime.hpp"
 #endif
 // Declaration and definition of StubGenerator (no .hpp file).
 // For a more detailed description of the stub routine structure
 // see the comment in stubRoutines.hpp
 #define __ _masm->
 #define a__ ((Assembler*)_masm)->
 #ifdef PRODUCT
 #define BLOCK_COMMENT(str) /* nothing */
 #else
 #define BLOCK_COMMENT(str) __ block_comment(str)
 #endif
 #define BIND(label) bind(label); BLOCK_COMMENT(#label ":")
 const int MXCSR_MASK  = 0xFFC0;  // Mask out any pending exceptions
 const int FPU_CNTRL_WRD_MASK = 0xFFFF;
 // -------------------------------------------------------------------------------------------------------------------------
 // Stub Code definitions
 static address handle_unsafe_access() {
   JavaThread* thread = JavaThread::current();
   address pc  = thread->saved_exception_pc();
   // pc is the instruction which we must emulate
   // doing a no-op is fine:  return garbage from the load
   // therefore, compute npc
   address npc = Assembler::locate_next_instruction(pc);
   // request an async exception
   thread->set_pending_unsafe_access_error();
   // return address of next instruction to execute
   return npc;
 }
 class StubGenerator: public StubCodeGenerator {
  private:
 #ifdef PRODUCT
 #define inc_counter_np(counter) (0)
 #else
   void inc_counter_np_(int& counter) {
     __ incrementl(ExternalAddress((address)&counter));
   }
 #define inc_counter_np(counter) \
   BLOCK_COMMENT("inc_counter " #counter); \
   inc_counter_np_(counter);
 #endif //PRODUCT
   void inc_copy_counter_np(BasicType t) {
 #ifndef PRODUCT
     switch (t) {
     case T_BYTE:    inc_counter_np(SharedRuntime::_jbyte_array_copy_ctr); return;
     case T_SHORT:   inc_counter_np(SharedRuntime::_jshort_array_copy_ctr); return;
     case T_INT:     inc_counter_np(SharedRuntime::_jint_array_copy_ctr); return;
     case T_LONG:    inc_counter_np(SharedRuntime::_jlong_array_copy_ctr); return;
     case T_OBJECT:  inc_counter_np(SharedRuntime::_oop_array_copy_ctr); return;
     }
     ShouldNotReachHere();
 #endif //PRODUCT
   }
   //------------------------------------------------------------------------------------------------------------------------
   // Call stubs are used to call Java from C
   //
   //    [ return_from_Java     ] <--- rsp
   //    [ argument word n      ]
   //      ...
   // -N [ argument word 1      ]
   // -7 [ Possible padding for stack alignment ]
   // -6 [ Possible padding for stack alignment ]
   // -5 [ Possible padding for stack alignment ]
   // -4 [ mxcsr save           ] <--- rsp_after_call
   // -3 [ saved rbx,            ]
   // -2 [ saved rsi            ]
   // -1 [ saved rdi            ]
   //  0 [ saved rbp,            ] <--- rbp,
   //  1 [ return address       ]
   //  2 [ ptr. to call wrapper ]
   //  3 [ result               ]
   //  4 [ result_type          ]
   //  5 [ method               ]
   //  6 [ entry_point          ]
   //  7 [ parameters           ]
   //  8 [ parameter_size       ]
   //  9 [ thread               ]
   address generate_call_stub(address& return_address) {
     StubCodeMark mark(this, "StubRoutines", "call_stub");
     address start = __ pc();
     // stub code parameters / addresses
     assert(frame::entry_frame_call_wrapper_offset == 2, "adjust this code");
     bool  sse_save = false;
     const Address rsp_after_call(rbp, -4 * wordSize); // same as in generate_catch_exception()!
     const int     locals_count_in_bytes  (4*wordSize);
     const Address mxcsr_save    (rbp, -4 * wordSize);
     const Address saved_rbx     (rbp, -3 * wordSize);
     const Address saved_rsi     (rbp, -2 * wordSize);
     const Address saved_rdi     (rbp, -1 * wordSize);
     const Address result        (rbp,  3 * wordSize);
     const Address result_type   (rbp,  4 * wordSize);
     const Address method        (rbp,  5 * wordSize);
     const Address entry_point   (rbp,  6 * wordSize);
     const Address parameters    (rbp,  7 * wordSize);
     const Address parameter_size(rbp,  8 * wordSize);
     const Address thread        (rbp,  9 * wordSize); // same as in generate_catch_exception()!
     sse_save =  UseSSE > 0;
     // stub code
     __ enter();
     __ movptr(rcx, parameter_size);              // parameter counter
     __ shlptr(rcx, Interpreter::logStackElementSize); // convert parameter count to bytes
     __ addptr(rcx, locals_count_in_bytes);       // reserve space for register saves
     __ subptr(rsp, rcx);
     __ andptr(rsp, -(StackAlignmentInBytes));    // Align stack
     // save rdi, rsi, & rbx, according to C calling conventions
     __ movptr(saved_rdi, rdi);
     __ movptr(saved_rsi, rsi);
     __ movptr(saved_rbx, rbx);
     // save and initialize %mxcsr
     if (sse_save) {
       Label skip_ldmx;
       __ stmxcsr(mxcsr_save);
       __ movl(rax, mxcsr_save);
       __ andl(rax, MXCSR_MASK);    // Only check control and mask bits
       ExternalAddress mxcsr_std(StubRoutines::addr_mxcsr_std());
       __ cmp32(rax, mxcsr_std);
       __ jcc(Assembler::equal, skip_ldmx);
       __ ldmxcsr(mxcsr_std);
       __ bind(skip_ldmx);
     }
     // make sure the control word is correct.
     __ fldcw(ExternalAddress(StubRoutines::addr_fpu_cntrl_wrd_std()));
 #ifdef ASSERT
     // make sure we have no pending exceptions
     { Label L;
       __ movptr(rcx, thread);
       __ cmpptr(Address(rcx, Thread::pending_exception_offset()), (int32_t)NULL_WORD);
       __ jcc(Assembler::equal, L);
       __ stop("StubRoutines::call_stub: entered with pending exception");
       __ bind(L);
     }
 #endif
     // pass parameters if any
     BLOCK_COMMENT("pass parameters if any");
     Label parameters_done;
     __ movl(rcx, parameter_size);  // parameter counter
     __ testl(rcx, rcx);
     __ jcc(Assembler::zero, parameters_done);
     // parameter passing loop
     Label loop;
     // Copy Java parameters in reverse order (receiver last)
     // Note that the argument order is inverted in the process
     // source is rdx[rcx: N-1..0]
     // dest   is rsp[rbx: 0..N-1]
     __ movptr(rdx, parameters);          // parameter pointer
     __ xorptr(rbx, rbx);
     __ BIND(loop);
     // get parameter
     __ movptr(rax, Address(rdx, rcx, Interpreter::stackElementScale(), -wordSize));
     __ movptr(Address(rsp, rbx, Interpreter::stackElementScale(),
                     Interpreter::expr_offset_in_bytes(0)), rax);          // store parameter
     __ increment(rbx);
     __ decrement(rcx);
     __ jcc(Assembler::notZero, loop);
     // call Java function
     __ BIND(parameters_done);
     __ movptr(rbx, method);           // get methodOop
     __ movptr(rax, entry_point);      // get entry_point
     __ mov(rsi, rsp);                 // set sender sp
     BLOCK_COMMENT("call Java function");
     __ call(rax);
     BLOCK_COMMENT("call_stub_return_address:");
     return_address = __ pc();
 #ifdef COMPILER2
     {
       Label L_skip;
       if (UseSSE >= 2) {
         __ verify_FPU(0, "call_stub_return");
       } else {
         for (int i = 1; i < 8; i++) {
           __ ffree(i);
         }
         // UseSSE <= 1 so double result should be left on TOS
         __ movl(rsi, result_type);
         __ cmpl(rsi, T_DOUBLE);
         __ jcc(Assembler::equal, L_skip);
         if (UseSSE == 0) {
           // UseSSE == 0 so float result should be left on TOS
           __ cmpl(rsi, T_FLOAT);
           __ jcc(Assembler::equal, L_skip);
         }
         __ ffree(0);
       }
       __ BIND(L_skip);
     }
 #endif // COMPILER2
     // store result depending on type
     // (everything that is not T_LONG, T_FLOAT or T_DOUBLE is treated as T_INT)
     __ movptr(rdi, result);
     Label is_long, is_float, is_double, exit;
     __ movl(rsi, result_type);
     __ cmpl(rsi, T_LONG);
     __ jcc(Assembler::equal, is_long);
     __ cmpl(rsi, T_FLOAT);
     __ jcc(Assembler::equal, is_float);
     __ cmpl(rsi, T_DOUBLE);
     __ jcc(Assembler::equal, is_double);
     // handle T_INT case
     __ movl(Address(rdi, 0), rax);
     __ BIND(exit);
     // check that FPU stack is empty
     __ verify_FPU(0, "generate_call_stub");
     // pop parameters
     __ lea(rsp, rsp_after_call);
     // restore %mxcsr
     if (sse_save) {
       __ ldmxcsr(mxcsr_save);
     }
     // restore rdi, rsi and rbx,
     __ movptr(rbx, saved_rbx);
     __ movptr(rsi, saved_rsi);
     __ movptr(rdi, saved_rdi);
     __ addptr(rsp, 4*wordSize);
     // return
     __ pop(rbp);
     __ ret(0);
     // handle return types different from T_INT
     __ BIND(is_long);
     __ movl(Address(rdi, 0 * wordSize), rax);
     __ movl(Address(rdi, 1 * wordSize), rdx);
     __ jmp(exit);
     __ BIND(is_float);
     // interpreter uses xmm0 for return values
     if (UseSSE >= 1) {
       __ movflt(Address(rdi, 0), xmm0);
     } else {
       __ fstp_s(Address(rdi, 0));
     }
     __ jmp(exit);
     __ BIND(is_double);
     // interpreter uses xmm0 for return values
     if (UseSSE >= 2) {
       __ movdbl(Address(rdi, 0), xmm0);
     } else {
       __ fstp_d(Address(rdi, 0));
     }
     __ jmp(exit);
     return start;
   }
   //------------------------------------------------------------------------------------------------------------------------
   // Return point for a Java call if there's an exception thrown in Java code.
   // The exception is caught and transformed into a pending exception stored in
   // JavaThread that can be tested from within the VM.
   //
   // Note: Usually the parameters are removed by the callee. In case of an exception
   //       crossing an activation frame boundary, that is not the case if the callee
   //       is compiled code => need to setup the rsp.
   //
   // rax,: exception oop
   address generate_catch_exception() {
     StubCodeMark mark(this, "StubRoutines", "catch_exception");
     const Address rsp_after_call(rbp, -4 * wordSize); // same as in generate_call_stub()!
     const Address thread        (rbp,  9 * wordSize); // same as in generate_call_stub()!
     address start = __ pc();
     // get thread directly
     __ movptr(rcx, thread);
 #ifdef ASSERT
     // verify that threads correspond
     { Label L;
       __ get_thread(rbx);
       __ cmpptr(rbx, rcx);
       __ jcc(Assembler::equal, L);
       __ stop("StubRoutines::catch_exception: threads must correspond");
       __ bind(L);
     }
 #endif
     // set pending exception
     __ verify_oop(rax);
     __ movptr(Address(rcx, Thread::pending_exception_offset()), rax          );
     __ lea(Address(rcx, Thread::exception_file_offset   ()),
            ExternalAddress((address)__FILE__));
     __ movl(Address(rcx, Thread::exception_line_offset   ()), __LINE__ );
     // complete return to VM
     assert(StubRoutines::_call_stub_return_address != NULL, "_call_stub_return_address must have been generated before");
     __ jump(RuntimeAddress(StubRoutines::_call_stub_return_address));
     return start;
   }
   //------------------------------------------------------------------------------------------------------------------------
   // Continuation point for runtime calls returning with a pending exception.
   // The pending exception check happened in the runtime or native call stub.
   // The pending exception in Thread is converted into a Java-level exception.
   //
   // Contract with Java-level exception handlers:
   // rax: exception
   // rdx: throwing pc
   //
   // NOTE: At entry of this stub, exception-pc must be on stack !!
   address generate_forward_exception() {
     StubCodeMark mark(this, "StubRoutines", "forward exception");
     address start = __ pc();
     const Register thread = rcx;
     // other registers used in this stub
     const Register exception_oop = rax;
     const Register handler_addr  = rbx;
     const Register exception_pc  = rdx;
     // Upon entry, the sp points to the return address returning into Java
     // (interpreted or compiled) code; i.e., the return address becomes the
     // throwing pc.
     //
     // Arguments pushed before the runtime call are still on the stack but
     // the exception handler will reset the stack pointer -> ignore them.
     // A potential result in registers can be ignored as well.
 #ifdef ASSERT
     // make sure this code is only executed if there is a pending exception
     { Label L;
       __ get_thread(thread);
       __ cmpptr(Address(thread, Thread::pending_exception_offset()), (int32_t)NULL_WORD);
       __ jcc(Assembler::notEqual, L);
       __ stop("StubRoutines::forward exception: no pending exception (1)");
       __ bind(L);
     }
 #endif
     // compute exception handler into rbx,
     __ get_thread(thread);
     __ movptr(exception_pc, Address(rsp, 0));
     BLOCK_COMMENT("call exception_handler_for_return_address");
     __ call_VM_leaf(CAST_FROM_FN_PTR(address, SharedRuntime::exception_handler_for_return_address), thread, exception_pc);
     __ mov(handler_addr, rax);
     // setup rax & rdx, remove return address & clear pending exception
     __ get_thread(thread);
     __ pop(exception_pc);
     __ movptr(exception_oop, Address(thread, Thread::pending_exception_offset()));
     __ movptr(Address(thread, Thread::pending_exception_offset()), NULL_WORD);
 #ifdef ASSERT
     // make sure exception is set
     { Label L;
       __ testptr(exception_oop, exception_oop);
       __ jcc(Assembler::notEqual, L);
       __ stop("StubRoutines::forward exception: no pending exception (2)");
       __ bind(L);
     }
 #endif
     // Verify that there is really a valid exception in RAX.
     __ verify_oop(exception_oop);
     // continue at exception handler (return address removed)
     // rax: exception
     // rbx: exception handler
     // rdx: throwing pc
     __ jmp(handler_addr);
     return start;
   }
   //----------------------------------------------------------------------------------------------------
   // Support for jint Atomic::xchg(jint exchange_value, volatile jint* dest)
   //
   // xchg exists as far back as 8086, lock needed for MP only
   // Stack layout immediately after call:
   //
   // 0 [ret addr ] <--- rsp
   // 1 [  ex     ]
   // 2 [  dest   ]
   //
   // Result:   *dest <- ex, return (old *dest)
   //
   // Note: win32 does not currently use this code
   address generate_atomic_xchg() {
     StubCodeMark mark(this, "StubRoutines", "atomic_xchg");
     address start = __ pc();
     __ push(rdx);
     Address exchange(rsp, 2 * wordSize);
     Address dest_addr(rsp, 3 * wordSize);
     __ movl(rax, exchange);
     __ movptr(rdx, dest_addr);
     __ xchgl(rax, Address(rdx, 0));
     __ pop(rdx);
     __ ret(0);
     return start;
   }
   //----------------------------------------------------------------------------------------------------
   // Support for void verify_mxcsr()
   //
   // This routine is used with -Xcheck:jni to verify that native
   // JNI code does not return to Java code without restoring the
   // MXCSR register to our expected state.
   address generate_verify_mxcsr() {
     StubCodeMark mark(this, "StubRoutines", "verify_mxcsr");
     address start = __ pc();
     const Address mxcsr_save(rsp, 0);
     if (CheckJNICalls && UseSSE > 0 ) {
       Label ok_ret;
       ExternalAddress mxcsr_std(StubRoutines::addr_mxcsr_std());
       __ push(rax);
       __ subptr(rsp, wordSize);      // allocate a temp location
       __ stmxcsr(mxcsr_save);
       __ movl(rax, mxcsr_save);
       __ andl(rax, MXCSR_MASK);
       __ cmp32(rax, mxcsr_std);
       __ jcc(Assembler::equal, ok_ret);
       __ warn("MXCSR changed by native JNI code.");
       __ ldmxcsr(mxcsr_std);
       __ bind(ok_ret);
       __ addptr(rsp, wordSize);
       __ pop(rax);
     }
     __ ret(0);
     return start;
   }
   //---------------------------------------------------------------------------
   // Support for void verify_fpu_cntrl_wrd()
   //
   // This routine is used with -Xcheck:jni to verify that native
   // JNI code does not return to Java code without restoring the
   // FP control word to our expected state.
   address generate_verify_fpu_cntrl_wrd() {
     StubCodeMark mark(this, "StubRoutines", "verify_spcw");
     address start = __ pc();
     const Address fpu_cntrl_wrd_save(rsp, 0);
     if (CheckJNICalls) {
       Label ok_ret;
       __ push(rax);
       __ subptr(rsp, wordSize);      // allocate a temp location
       __ fnstcw(fpu_cntrl_wrd_save);
       __ movl(rax, fpu_cntrl_wrd_save);
       __ andl(rax, FPU_CNTRL_WRD_MASK);
       ExternalAddress fpu_std(StubRoutines::addr_fpu_cntrl_wrd_std());
       __ cmp32(rax, fpu_std);
       __ jcc(Assembler::equal, ok_ret);
       __ warn("Floating point control word changed by native JNI code.");
       __ fldcw(fpu_std);
       __ bind(ok_ret);
       __ addptr(rsp, wordSize);
       __ pop(rax);
     }
     __ ret(0);
     return start;
   }
   //---------------------------------------------------------------------------
   // Wrapper for slow-case handling of double-to-integer conversion
   // d2i or f2i fast case failed either because it is nan or because
   // of under/overflow.
   // Input:  FPU TOS: float value
   // Output: rax, (rdx): integer (long) result
   address generate_d2i_wrapper(BasicType t, address fcn) {
     StubCodeMark mark(this, "StubRoutines", "d2i_wrapper");
     address start = __ pc();
   // Capture info about frame layout
   enum layout { FPUState_off         = 0,
                 rbp_off              = FPUStateSizeInWords,
                 rdi_off,
                 rsi_off,
                 rcx_off,
                 rbx_off,
                 saved_argument_off,
                 saved_argument_off2, // 2nd half of double
                 framesize
   };
   assert(FPUStateSizeInWords == 27, "update stack layout");
     // Save outgoing argument to stack across push_FPU_state()
     __ subptr(rsp, wordSize * 2);
     __ fstp_d(Address(rsp, 0));
     // Save CPU & FPU state
     __ push(rbx);
     __ push(rcx);
     __ push(rsi);
     __ push(rdi);
     __ push(rbp);
     __ push_FPU_state();
     // push_FPU_state() resets the FP top of stack
     // Load original double into FP top of stack
     __ fld_d(Address(rsp, saved_argument_off * wordSize));
     // Store double into stack as outgoing argument
     __ subptr(rsp, wordSize*2);
     __ fst_d(Address(rsp, 0));
     // Prepare FPU for doing math in C-land
     __ empty_FPU_stack();
     // Call the C code to massage the double.  Result in EAX
     if (t == T_INT)
       { BLOCK_COMMENT("SharedRuntime::d2i"); }
     else if (t == T_LONG)
       { BLOCK_COMMENT("SharedRuntime::d2l"); }
     __ call_VM_leaf( fcn, 2 );
     // Restore CPU & FPU state
     __ pop_FPU_state();
     __ pop(rbp);
     __ pop(rdi);
     __ pop(rsi);
     __ pop(rcx);
     __ pop(rbx);
     __ addptr(rsp, wordSize * 2);
     __ ret(0);
     return start;
   }
   //---------------------------------------------------------------------------
   // The following routine generates a subroutine to throw an asynchronous
   // UnknownError when an unsafe access gets a fault that could not be
   // reasonably prevented by the programmer.  (Example: SIGBUS/OBJERR.)
   address generate_handler_for_unsafe_access() {
     StubCodeMark mark(this, "StubRoutines", "handler_for_unsafe_access");
     address start = __ pc();
     __ push(0);                       // hole for return address-to-be
     __ pusha();                       // push registers
     Address next_pc(rsp, RegisterImpl::number_of_registers * BytesPerWord);
     BLOCK_COMMENT("call handle_unsafe_access");
     __ call(RuntimeAddress(CAST_FROM_FN_PTR(address, handle_unsafe_access)));
     __ movptr(next_pc, rax);          // stuff next address
     __ popa();
     __ ret(0);                        // jump to next address
     return start;
   }
   //----------------------------------------------------------------------------------------------------
   // Non-destructive plausibility checks for oops
   address generate_verify_oop() {
     StubCodeMark mark(this, "StubRoutines", "verify_oop");
     address start = __ pc();
     // Incoming arguments on stack after saving rax,:
     //
     // [tos    ]: saved rdx
     // [tos + 1]: saved EFLAGS
     // [tos + 2]: return address
     // [tos + 3]: char* error message
     // [tos + 4]: oop   object to verify
     // [tos + 5]: saved rax, - saved by caller and bashed
     Label exit, error;
     __ pushf();
     __ incrementl(ExternalAddress((address) StubRoutines::verify_oop_count_addr()));
     __ push(rdx);                                // save rdx
     // make sure object is 'reasonable'
     __ movptr(rax, Address(rsp, 4 * wordSize));    // get object
     __ testptr(rax, rax);
     __ jcc(Assembler::zero, exit);               // if obj is NULL it is ok
     // Check if the oop is in the right area of memory
     const int oop_mask = Universe::verify_oop_mask();
     const int oop_bits = Universe::verify_oop_bits();
     __ mov(rdx, rax);
     __ andptr(rdx, oop_mask);
     __ cmpptr(rdx, oop_bits);
     __ jcc(Assembler::notZero, error);
     // make sure klass is 'reasonable'
     __ movptr(rax, Address(rax, oopDesc::klass_offset_in_bytes())); // get klass
     __ testptr(rax, rax);
     __ jcc(Assembler::zero, error);              // if klass is NULL it is broken
     // Check if the klass is in the right area of memory
     const int klass_mask = Universe::verify_klass_mask();
     const int klass_bits = Universe::verify_klass_bits();
     __ mov(rdx, rax);
     __ andptr(rdx, klass_mask);
     __ cmpptr(rdx, klass_bits);
     __ jcc(Assembler::notZero, error);
     // make sure klass' klass is 'reasonable'
     __ movptr(rax, Address(rax, oopDesc::klass_offset_in_bytes())); // get klass' klass
     __ testptr(rax, rax);
     __ jcc(Assembler::zero, error);              // if klass' klass is NULL it is broken
     __ mov(rdx, rax);
     __ andptr(rdx, klass_mask);
     __ cmpptr(rdx, klass_bits);
     __ jcc(Assembler::notZero, error);           // if klass not in right area
                                                  // of memory it is broken too.
     // return if everything seems ok
     __ bind(exit);
     __ movptr(rax, Address(rsp, 5 * wordSize));  // get saved rax, back
     __ pop(rdx);                                 // restore rdx
     __ popf();                                   // restore EFLAGS
     __ ret(3 * wordSize);                        // pop arguments
     // handle errors
     __ bind(error);
     __ movptr(rax, Address(rsp, 5 * wordSize));  // get saved rax, back
     __ pop(rdx);                                 // get saved rdx back
     __ popf();                                   // get saved EFLAGS off stack -- will be ignored
     __ pusha();                                  // push registers (eip = return address & msg are already pushed)
     BLOCK_COMMENT("call MacroAssembler::debug");
     __ call(RuntimeAddress(CAST_FROM_FN_PTR(address, MacroAssembler::debug32)));
     __ popa();
     __ ret(3 * wordSize);                        // pop arguments
     return start;
   }
   //
   //  Generate pre-barrier for array stores
   //
   //  Input:
   //     start   -  starting address
   //     count   -  element count
   void  gen_write_ref_array_pre_barrier(Register start, Register count, bool uninitialized_target) {
     assert_different_registers(start, count);
     BarrierSet* bs = Universe::heap()->barrier_set();
     switch (bs->kind()) {
       case BarrierSet::G1SATBCT:
       case BarrierSet::G1SATBCTLogging:
         // With G1, don't generate the call if we statically know that the target in uninitialized
         if (!uninitialized_target) {
            __ pusha();                      // push registers
            __ call_VM_leaf(CAST_FROM_FN_PTR(address, BarrierSet::static_write_ref_array_pre),
                            start, count);
            __ popa();
          }
         break;
       case BarrierSet::CardTableModRef:
       case BarrierSet::CardTableExtension:
       case BarrierSet::ModRef:
         break;
       default      :
         ShouldNotReachHere();
     }
   }
   //
   // Generate a post-barrier for an array store
   //
   //     start    -  starting address
   //     count    -  element count
   //
   //  The two input registers are overwritten.
   //
   void  gen_write_ref_array_post_barrier(Register start, Register count) {
     BarrierSet* bs = Universe::heap()->barrier_set();
     assert_different_registers(start, count);
     switch (bs->kind()) {
       case BarrierSet::G1SATBCT:
       case BarrierSet::G1SATBCTLogging:
         {
           __ pusha();                      // push registers
           __ call_VM_leaf(CAST_FROM_FN_PTR(address, BarrierSet::static_write_ref_array_post),
                           start, count);
           __ popa();
         }
         break;
       case BarrierSet::CardTableModRef:
       case BarrierSet::CardTableExtension:
         {
           CardTableModRefBS* ct = (CardTableModRefBS*)bs;
           assert(sizeof(*ct->byte_map_base) == sizeof(jbyte), "adjust this code");
           Label L_loop;
           const Register end = count;  // elements count; end == start+count-1
           assert_different_registers(start, end);
           __ lea(end,  Address(start, count, Address::times_ptr, -wordSize));
           __ shrptr(start, CardTableModRefBS::card_shift);
           __ shrptr(end,   CardTableModRefBS::card_shift);
           __ subptr(end, start); // end --> count
         __ BIND(L_loop);
           intptr_t disp = (intptr_t) ct->byte_map_base;
           Address cardtable(start, count, Address::times_1, disp);
           __ movb(cardtable, 0);
           __ decrement(count);
           __ jcc(Assembler::greaterEqual, L_loop);
         }
         break;
       case BarrierSet::ModRef:
         break;
       default      :
         ShouldNotReachHere();
     }
   }
   // Copy 64 bytes chunks
   //
   // Inputs:
   //   from        - source array address
   //   to_from     - destination array address - from
   //   qword_count - 8-bytes element count, negative
   //
   void xmm_copy_forward(Register from, Register to_from, Register qword_count) {
     assert( UseSSE >= 2, "supported cpu only" );
     Label L_copy_64_bytes_loop, L_copy_64_bytes, L_copy_8_bytes, L_exit;
     // Copy 64-byte chunks
     __ jmpb(L_copy_64_bytes);
     __ align(OptoLoopAlignment);
   __ BIND(L_copy_64_bytes_loop);
     if(UseUnalignedLoadStores) {
       __ movdqu(xmm0, Address(from, 0));
       __ movdqu(Address(from, to_from, Address::times_1, 0), xmm0);
       __ movdqu(xmm1, Address(from, 16));
       __ movdqu(Address(from, to_from, Address::times_1, 16), xmm1);
       __ movdqu(xmm2, Address(from, 32));
       __ movdqu(Address(from, to_from, Address::times_1, 32), xmm2);
       __ movdqu(xmm3, Address(from, 48));
       __ movdqu(Address(from, to_from, Address::times_1, 48), xmm3);
     } else {
       __ movq(xmm0, Address(from, 0));
       __ movq(Address(from, to_from, Address::times_1, 0), xmm0);
       __ movq(xmm1, Address(from, 8));
       __ movq(Address(from, to_from, Address::times_1, 8), xmm1);
       __ movq(xmm2, Address(from, 16));
       __ movq(Address(from, to_from, Address::times_1, 16), xmm2);
       __ movq(xmm3, Address(from, 24));
       __ movq(Address(from, to_from, Address::times_1, 24), xmm3);
       __ movq(xmm4, Address(from, 32));
       __ movq(Address(from, to_from, Address::times_1, 32), xmm4);
       __ movq(xmm5, Address(from, 40));
       __ movq(Address(from, to_from, Address::times_1, 40), xmm5);
       __ movq(xmm6, Address(from, 48));
       __ movq(Address(from, to_from, Address::times_1, 48), xmm6);
       __ movq(xmm7, Address(from, 56));
       __ movq(Address(from, to_from, Address::times_1, 56), xmm7);
     }
     __ addl(from, 64);
   __ BIND(L_copy_64_bytes);
     __ subl(qword_count, 8);
     __ jcc(Assembler::greaterEqual, L_copy_64_bytes_loop);
     __ addl(qword_count, 8);
     __ jccb(Assembler::zero, L_exit);
     //
     // length is too short, just copy qwords
     //
   __ BIND(L_copy_8_bytes);
     __ movq(xmm0, Address(from, 0));
     __ movq(Address(from, to_from, Address::times_1), xmm0);
     __ addl(from, 8);
     __ decrement(qword_count);
     __ jcc(Assembler::greater, L_copy_8_bytes);
   __ BIND(L_exit);
   }
   // Copy 64 bytes chunks
   //
   // Inputs:
   //   from        - source array address
   //   to_from     - destination array address - from
   //   qword_count - 8-bytes element count, negative
   //
   void mmx_copy_forward(Register from, Register to_from, Register qword_count) {
     assert( VM_Version::supports_mmx(), "supported cpu only" );
     Label L_copy_64_bytes_loop, L_copy_64_bytes, L_copy_8_bytes, L_exit;
     // Copy 64-byte chunks
     __ jmpb(L_copy_64_bytes);
     __ align(OptoLoopAlignment);
   __ BIND(L_copy_64_bytes_loop);
     __ movq(mmx0, Address(from, 0));
     __ movq(mmx1, Address(from, 8));
     __ movq(mmx2, Address(from, 16));
     __ movq(Address(from, to_from, Address::times_1, 0), mmx0);
     __ movq(mmx3, Address(from, 24));
     __ movq(Address(from, to_from, Address::times_1, 8), mmx1);
     __ movq(mmx4, Address(from, 32));
     __ movq(Address(from, to_from, Address::times_1, 16), mmx2);
     __ movq(mmx5, Address(from, 40));
     __ movq(Address(from, to_from, Address::times_1, 24), mmx3);
     __ movq(mmx6, Address(from, 48));
     __ movq(Address(from, to_from, Address::times_1, 32), mmx4);
     __ movq(mmx7, Address(from, 56));
     __ movq(Address(from, to_from, Address::times_1, 40), mmx5);
     __ movq(Address(from, to_from, Address::times_1, 48), mmx6);
     __ movq(Address(from, to_from, Address::times_1, 56), mmx7);
     __ addptr(from, 64);
   __ BIND(L_copy_64_bytes);
     __ subl(qword_count, 8);
     __ jcc(Assembler::greaterEqual, L_copy_64_bytes_loop);
     __ addl(qword_count, 8);
     __ jccb(Assembler::zero, L_exit);
     //
     // length is too short, just copy qwords
     //
   __ BIND(L_copy_8_bytes);
     __ movq(mmx0, Address(from, 0));
     __ movq(Address(from, to_from, Address::times_1), mmx0);
     __ addptr(from, 8);
     __ decrement(qword_count);
     __ jcc(Assembler::greater, L_copy_8_bytes);
   __ BIND(L_exit);
     __ emms();
   }
   address generate_disjoint_copy(BasicType t, bool aligned,
                                  Address::ScaleFactor sf,
                                  address* entry, const char *name,
                                  bool dest_uninitialized = false) {
     __ align(CodeEntryAlignment);
     StubCodeMark mark(this, "StubRoutines", name);
     address start = __ pc();
     Label L_0_count, L_exit, L_skip_align1, L_skip_align2, L_copy_byte;
     Label L_copy_2_bytes, L_copy_4_bytes, L_copy_64_bytes;
     int shift = Address::times_ptr - sf;
     const Register from     = rsi;  // source array address
     const Register to       = rdi;  // destination array address
     const Register count    = rcx;  // elements count
     const Register to_from  = to;   // (to - from)
     const Register saved_to = rdx;  // saved destination array address
     __ enter(); // required for proper stackwalking of RuntimeStub frame
     __ push(rsi);
     __ push(rdi);
     __ movptr(from , Address(rsp, 12+ 4));
     __ movptr(to   , Address(rsp, 12+ 8));
     __ movl(count, Address(rsp, 12+ 12));
     if (entry != NULL) {
       *entry = __ pc(); // Entry point from conjoint arraycopy stub.
       BLOCK_COMMENT("Entry:");
     }
     if (t == T_OBJECT) {
       __ testl(count, count);
       __ jcc(Assembler::zero, L_0_count);
       gen_write_ref_array_pre_barrier(to, count, dest_uninitialized);
       __ mov(saved_to, to);          // save 'to'
     }
     __ subptr(to, from); // to --> to_from
     __ cmpl(count, 2<<shift); // Short arrays (< 8 bytes) copy by element
     __ jcc(Assembler::below, L_copy_4_bytes); // use unsigned cmp
     if (!UseUnalignedLoadStores && !aligned && (t == T_BYTE || t == T_SHORT)) {
       // align source address at 4 bytes address boundary
       if (t == T_BYTE) {
         // One byte misalignment happens only for byte arrays
         __ testl(from, 1);
         __ jccb(Assembler::zero, L_skip_align1);
         __ movb(rax, Address(from, 0));
         __ movb(Address(from, to_from, Address::times_1, 0), rax);
         __ increment(from);
         __ decrement(count);
       __ BIND(L_skip_align1);
       }
       // Two bytes misalignment happens only for byte and short (char) arrays
       __ testl(from, 2);
       __ jccb(Assembler::zero, L_skip_align2);
       __ movw(rax, Address(from, 0));
       __ movw(Address(from, to_from, Address::times_1, 0), rax);
       __ addptr(from, 2);
       __ subl(count, 1<<(shift-1));
     __ BIND(L_skip_align2);
     }
     if (!VM_Version::supports_mmx()) {
       __ mov(rax, count);      // save 'count'
       __ shrl(count, shift); // bytes count
       __ addptr(to_from, from);// restore 'to'
       __ rep_mov();
       __ subptr(to_from, from);// restore 'to_from'
       __ mov(count, rax);      // restore 'count'
       __ jmpb(L_copy_2_bytes); // all dwords were copied
     } else {
       if (!UseUnalignedLoadStores) {
         // align to 8 bytes, we know we are 4 byte aligned to start
         __ testptr(from, 4);
         __ jccb(Assembler::zero, L_copy_64_bytes);
         __ movl(rax, Address(from, 0));
         __ movl(Address(from, to_from, Address::times_1, 0), rax);
         __ addptr(from, 4);
         __ subl(count, 1<<shift);
       }
     __ BIND(L_copy_64_bytes);
       __ mov(rax, count);
       __ shrl(rax, shift+1);  // 8 bytes chunk count
       //
       // Copy 8-byte chunks through MMX registers, 8 per iteration of the loop
       //
       if (UseXMMForArrayCopy) {
         xmm_copy_forward(from, to_from, rax);
       } else {
         mmx_copy_forward(from, to_from, rax);
       }
     }
     // copy tailing dword
   __ BIND(L_copy_4_bytes);
     __ testl(count, 1<<shift);
     __ jccb(Assembler::zero, L_copy_2_bytes);
     __ movl(rax, Address(from, 0));
     __ movl(Address(from, to_from, Address::times_1, 0), rax);
     if (t == T_BYTE || t == T_SHORT) {
       __ addptr(from, 4);
     __ BIND(L_copy_2_bytes);
       // copy tailing word
       __ testl(count, 1<<(shift-1));
       __ jccb(Assembler::zero, L_copy_byte);
       __ movw(rax, Address(from, 0));
       __ movw(Address(from, to_from, Address::times_1, 0), rax);
       if (t == T_BYTE) {
         __ addptr(from, 2);
       __ BIND(L_copy_byte);
         // copy tailing byte
         __ testl(count, 1);
         __ jccb(Assembler::zero, L_exit);
         __ movb(rax, Address(from, 0));
         __ movb(Address(from, to_from, Address::times_1, 0), rax);
       __ BIND(L_exit);
       } else {
       __ BIND(L_copy_byte);
       }
     } else {
     __ BIND(L_copy_2_bytes);
     }
     if (t == T_OBJECT) {
       __ movl(count, Address(rsp, 12+12)); // reread 'count'
       __ mov(to, saved_to); // restore 'to'
       gen_write_ref_array_post_barrier(to, count);
     __ BIND(L_0_count);
     }
     inc_copy_counter_np(t);
     __ pop(rdi);
     __ pop(rsi);
     __ leave(); // required for proper stackwalking of RuntimeStub frame
     __ xorptr(rax, rax); // return 0
     __ ret(0);
     return start;
   }
   address generate_fill(BasicType t, bool aligned, const char *name) {
     __ align(CodeEntryAlignment);
     StubCodeMark mark(this, "StubRoutines", name);
     address start = __ pc();
     BLOCK_COMMENT("Entry:");
     const Register to       = rdi;  // source array address
     const Register value    = rdx;  // value
     const Register count    = rsi;  // elements count
     __ enter(); // required for proper stackwalking of RuntimeStub frame
     __ push(rsi);
     __ push(rdi);
     __ movptr(to   , Address(rsp, 12+ 4));
     __ movl(value, Address(rsp, 12+ 8));
     __ movl(count, Address(rsp, 12+ 12));
     __ generate_fill(t, aligned, to, value, count, rax, xmm0);
     __ pop(rdi);
     __ pop(rsi);
     __ leave(); // required for proper stackwalking of RuntimeStub frame
     __ ret(0);
     return start;
   }
   address generate_conjoint_copy(BasicType t, bool aligned,
                                  Address::ScaleFactor sf,
                                  address nooverlap_target,
                                  address* entry, const char *name,
                                  bool dest_uninitialized = false) {
     __ align(CodeEntryAlignment);
     StubCodeMark mark(this, "StubRoutines", name);
     address start = __ pc();
     Label L_0_count, L_exit, L_skip_align1, L_skip_align2, L_copy_byte;
     Label L_copy_2_bytes, L_copy_4_bytes, L_copy_8_bytes, L_copy_8_bytes_loop;
     int shift = Address::times_ptr - sf;
     const Register src   = rax;  // source array address
     const Register dst   = rdx;  // destination array address
     const Register from  = rsi;  // source array address
     const Register to    = rdi;  // destination array address
     const Register count = rcx;  // elements count
     const Register end   = rax;  // array end address
     __ enter(); // required for proper stackwalking of RuntimeStub frame
     __ push(rsi);
     __ push(rdi);
     __ movptr(src  , Address(rsp, 12+ 4));   // from
     __ movptr(dst  , Address(rsp, 12+ 8));   // to
     __ movl2ptr(count, Address(rsp, 12+12)); // count
     if (entry != NULL) {
       *entry = __ pc(); // Entry point from generic arraycopy stub.
       BLOCK_COMMENT("Entry:");
     }
     // nooverlap_target expects arguments in rsi and rdi.
     __ mov(from, src);
     __ mov(to  , dst);
     // arrays overlap test: dispatch to disjoint stub if necessary.
     RuntimeAddress nooverlap(nooverlap_target);
     __ cmpptr(dst, src);
     __ lea(end, Address(src, count, sf, 0)); // src + count * elem_size
     __ jump_cc(Assembler::belowEqual, nooverlap);
     __ cmpptr(dst, end);
     __ jump_cc(Assembler::aboveEqual, nooverlap);
     if (t == T_OBJECT) {
       __ testl(count, count);
       __ jcc(Assembler::zero, L_0_count);
       gen_write_ref_array_pre_barrier(dst, count, dest_uninitialized);
     }
     // copy from high to low
     __ cmpl(count, 2<<shift); // Short arrays (< 8 bytes) copy by element
     __ jcc(Assembler::below, L_copy_4_bytes); // use unsigned cmp
     if (t == T_BYTE || t == T_SHORT) {
       // Align the end of destination array at 4 bytes address boundary
       __ lea(end, Address(dst, count, sf, 0));
       if (t == T_BYTE) {
         // One byte misalignment happens only for byte arrays
         __ testl(end, 1);
         __ jccb(Assembler::zero, L_skip_align1);
         __ decrement(count);
         __ movb(rdx, Address(from, count, sf, 0));
         __ movb(Address(to, count, sf, 0), rdx);
       __ BIND(L_skip_align1);
       }
       // Two bytes misalignment happens only for byte and short (char) arrays
       __ testl(end, 2);
       __ jccb(Assembler::zero, L_skip_align2);
       __ subptr(count, 1<<(shift-1));
       __ movw(rdx, Address(from, count, sf, 0));
       __ movw(Address(to, count, sf, 0), rdx);
     __ BIND(L_skip_align2);
       __ cmpl(count, 2<<shift); // Short arrays (< 8 bytes) copy by element
       __ jcc(Assembler::below, L_copy_4_bytes);
     }
     if (!VM_Version::supports_mmx()) {
       __ std();
       __ mov(rax, count); // Save 'count'
       __ mov(rdx, to);    // Save 'to'
       __ lea(rsi, Address(from, count, sf, -4));
       __ lea(rdi, Address(to  , count, sf, -4));
       __ shrptr(count, shift); // bytes count
       __ rep_mov();
       __ cld();
       __ mov(count, rax); // restore 'count'
       __ andl(count, (1<<shift)-1);      // mask the number of rest elements
       __ movptr(from, Address(rsp, 12+4)); // reread 'from'
       __ mov(to, rdx);   // restore 'to'
       __ jmpb(L_copy_2_bytes); // all dword were copied
    } else {
       // Align to 8 bytes the end of array. It is aligned to 4 bytes already.
       __ testptr(end, 4);
       __ jccb(Assembler::zero, L_copy_8_bytes);
       __ subl(count, 1<<shift);
       __ movl(rdx, Address(from, count, sf, 0));
       __ movl(Address(to, count, sf, 0), rdx);
       __ jmpb(L_copy_8_bytes);
       __ align(OptoLoopAlignment);
       // Move 8 bytes
     __ BIND(L_copy_8_bytes_loop);
       if (UseXMMForArrayCopy) {
         __ movq(xmm0, Address(from, count, sf, 0));
         __ movq(Address(to, count, sf, 0), xmm0);
       } else {
         __ movq(mmx0, Address(from, count, sf, 0));
         __ movq(Address(to, count, sf, 0), mmx0);
       }
     __ BIND(L_copy_8_bytes);
       __ subl(count, 2<<shift);
       __ jcc(Assembler::greaterEqual, L_copy_8_bytes_loop);
       __ addl(count, 2<<shift);
       if (!UseXMMForArrayCopy) {
         __ emms();
       }
     }
   __ BIND(L_copy_4_bytes);
     // copy prefix qword
     __ testl(count, 1<<shift);
     __ jccb(Assembler::zero, L_copy_2_bytes);
     __ movl(rdx, Address(from, count, sf, -4));
     __ movl(Address(to, count, sf, -4), rdx);
     if (t == T_BYTE || t == T_SHORT) {
         __ subl(count, (1<<shift));
       __ BIND(L_copy_2_bytes);
         // copy prefix dword
         __ testl(count, 1<<(shift-1));
         __ jccb(Assembler::zero, L_copy_byte);
         __ movw(rdx, Address(from, count, sf, -2));
         __ movw(Address(to, count, sf, -2), rdx);
         if (t == T_BYTE) {
           __ subl(count, 1<<(shift-1));
         __ BIND(L_copy_byte);
           // copy prefix byte
           __ testl(count, 1);
           __ jccb(Assembler::zero, L_exit);
           __ movb(rdx, Address(from, 0));
           __ movb(Address(to, 0), rdx);
         __ BIND(L_exit);
         } else {
         __ BIND(L_copy_byte);
         }
     } else {
     __ BIND(L_copy_2_bytes);
     }
     if (t == T_OBJECT) {
       __ movl2ptr(count, Address(rsp, 12+12)); // reread count
       gen_write_ref_array_post_barrier(to, count);
     __ BIND(L_0_count);
     }
     inc_copy_counter_np(t);
     __ pop(rdi);
     __ pop(rsi);
     __ leave(); // required for proper stackwalking of RuntimeStub frame
     __ xorptr(rax, rax); // return 0
     __ ret(0);
     return start;
   }
   address generate_disjoint_long_copy(address* entry, const char *name) {
     __ align(CodeEntryAlignment);
     StubCodeMark mark(this, "StubRoutines", name);
     address start = __ pc();
     Label L_copy_8_bytes, L_copy_8_bytes_loop;
     const Register from       = rax;  // source array address
     const Register to         = rdx;  // destination array address
     const Register count      = rcx;  // elements count
     const Register to_from    = rdx;  // (to - from)
     __ enter(); // required for proper stackwalking of RuntimeStub frame
     __ movptr(from , Address(rsp, 8+0));       // from
     __ movptr(to   , Address(rsp, 8+4));       // to
     __ movl2ptr(count, Address(rsp, 8+8));     // count
     *entry = __ pc(); // Entry point from conjoint arraycopy stub.
     BLOCK_COMMENT("Entry:");
     __ subptr(to, from); // to --> to_from
     if (VM_Version::supports_mmx()) {
       if (UseXMMForArrayCopy) {
         xmm_copy_forward(from, to_from, count);
       } else {
         mmx_copy_forward(from, to_from, count);
       }
     } else {
       __ jmpb(L_copy_8_bytes);
       __ align(OptoLoopAlignment);
     __ BIND(L_copy_8_bytes_loop);
       __ fild_d(Address(from, 0));
       __ fistp_d(Address(from, to_from, Address::times_1));
       __ addptr(from, 8);
     __ BIND(L_copy_8_bytes);
       __ decrement(count);
       __ jcc(Assembler::greaterEqual, L_copy_8_bytes_loop);
     }
     inc_copy_counter_np(T_LONG);
     __ leave(); // required for proper stackwalking of RuntimeStub frame
     __ xorptr(rax, rax); // return 0
     __ ret(0);
     return start;
   }
   address generate_conjoint_long_copy(address nooverlap_target,
                                       address* entry, const char *name) {
     __ align(CodeEntryAlignment);
     StubCodeMark mark(this, "StubRoutines", name);
     address start = __ pc();
     Label L_copy_8_bytes, L_copy_8_bytes_loop;
     const Register from       = rax;  // source array address
     const Register to         = rdx;  // destination array address
     const Register count      = rcx;  // elements count
     const Register end_from   = rax;  // source array end address
     __ enter(); // required for proper stackwalking of RuntimeStub frame
     __ movptr(from , Address(rsp, 8+0));       // from
     __ movptr(to   , Address(rsp, 8+4));       // to
     __ movl2ptr(count, Address(rsp, 8+8));     // count
     *entry = __ pc(); // Entry point from generic arraycopy stub.
     BLOCK_COMMENT("Entry:");
     // arrays overlap test
     __ cmpptr(to, from);
     RuntimeAddress nooverlap(nooverlap_target);
     __ jump_cc(Assembler::belowEqual, nooverlap);
     __ lea(end_from, Address(from, count, Address::times_8, 0));
     __ cmpptr(to, end_from);
     __ movptr(from, Address(rsp, 8));  // from
     __ jump_cc(Assembler::aboveEqual, nooverlap);
     __ jmpb(L_copy_8_bytes);
     __ align(OptoLoopAlignment);
   __ BIND(L_copy_8_bytes_loop);
     if (VM_Version::supports_mmx()) {
       if (UseXMMForArrayCopy) {
         __ movq(xmm0, Address(from, count, Address::times_8));
         __ movq(Address(to, count, Address::times_8), xmm0);
       } else {
         __ movq(mmx0, Address(from, count, Address::times_8));
         __ movq(Address(to, count, Address::times_8), mmx0);
       }
     } else {
       __ fild_d(Address(from, count, Address::times_8));
       __ fistp_d(Address(to, count, Address::times_8));
     }
   __ BIND(L_copy_8_bytes);
     __ decrement(count);
     __ jcc(Assembler::greaterEqual, L_copy_8_bytes_loop);
     if (VM_Version::supports_mmx() && !UseXMMForArrayCopy) {
       __ emms();
     }
     inc_copy_counter_np(T_LONG);
     __ leave(); // required for proper stackwalking of RuntimeStub frame
     __ xorptr(rax, rax); // return 0
     __ ret(0);
     return start;
   }
   // Helper for generating a dynamic type check.
   // The sub_klass must be one of {rbx, rdx, rsi}.
   // The temp is killed.
   void generate_type_check(Register sub_klass,
                            Address& super_check_offset_addr,
                            Address& super_klass_addr,
                            Register temp,
                            Label* L_success, Label* L_failure) {
     BLOCK_COMMENT("type_check:");
     Label L_fallthrough;
 #define LOCAL_JCC(assembler_con, label_ptr)                             \
     if (label_ptr != NULL)  __ jcc(assembler_con, *(label_ptr));        \
     else                    __ jcc(assembler_con, L_fallthrough) /*omit semi*/
     // The following is a strange variation of the fast path which requires
     // one less register, because needed values are on the argument stack.
     // __ check_klass_subtype_fast_path(sub_klass, *super_klass*, temp,
     //                                  L_success, L_failure, NULL);
     assert_different_registers(sub_klass, temp);
     int sc_offset = (klassOopDesc::header_size() * HeapWordSize +
                      Klass::secondary_super_cache_offset_in_bytes());
     // if the pointers are equal, we are done (e.g., String[] elements)
     __ cmpptr(sub_klass, super_klass_addr);
     LOCAL_JCC(Assembler::equal, L_success);
     // check the supertype display:
     __ movl2ptr(temp, super_check_offset_addr);
     Address super_check_addr(sub_klass, temp, Address::times_1, 0);
     __ movptr(temp, super_check_addr); // load displayed supertype
     __ cmpptr(temp, super_klass_addr); // test the super type
     LOCAL_JCC(Assembler::equal, L_success);
     // if it was a primary super, we can just fail immediately
     __ cmpl(super_check_offset_addr, sc_offset);
     LOCAL_JCC(Assembler::notEqual, L_failure);
     // The repne_scan instruction uses fixed registers, which will get spilled.
     // We happen to know this works best when super_klass is in rax.
     Register super_klass = temp;
     __ movptr(super_klass, super_klass_addr);
     __ check_klass_subtype_slow_path(sub_klass, super_klass, noreg, noreg,
                                      L_success, L_failure);
     __ bind(L_fallthrough);
     if (L_success == NULL) { BLOCK_COMMENT("L_success:"); }
     if (L_failure == NULL) { BLOCK_COMMENT("L_failure:"); }
 #undef LOCAL_JCC
   }
   //
   //  Generate checkcasting array copy stub
   //
   //  Input:
   //    4(rsp)   - source array address
   //    8(rsp)   - destination array address
   //   12(rsp)   - element count, can be zero
   //   16(rsp)   - size_t ckoff (super_check_offset)
   //   20(rsp)   - oop ckval (super_klass)
   //
   //  Output:
   //    rax, ==  0  -  success
   //    rax, == -1^K - failure, where K is partial transfer count
   //
   address generate_checkcast_copy(const char *name, address* entry, bool dest_uninitialized = false) {
     __ align(CodeEntryAlignment);
     StubCodeMark mark(this, "StubRoutines", name);
     address start = __ pc();
     Label L_load_element, L_store_element, L_do_card_marks, L_done;
     // register use:
     //  rax, rdx, rcx -- loop control (end_from, end_to, count)
     //  rdi, rsi      -- element access (oop, klass)
     //  rbx,           -- temp
     const Register from       = rax;    // source array address
     const Register to         = rdx;    // destination array address
     const Register length     = rcx;    // elements count
     const Register elem       = rdi;    // each oop copied
     const Register elem_klass = rsi;    // each elem._klass (sub_klass)
     const Register temp       = rbx;    // lone remaining temp
     __ enter(); // required for proper stackwalking of RuntimeStub frame
     __ push(rsi);
     __ push(rdi);
     __ push(rbx);
     Address   from_arg(rsp, 16+ 4);     // from
     Address     to_arg(rsp, 16+ 8);     // to
     Address length_arg(rsp, 16+12);     // elements count
     Address  ckoff_arg(rsp, 16+16);     // super_check_offset
     Address  ckval_arg(rsp, 16+20);     // super_klass
     // Load up:
     __ movptr(from,     from_arg);
     __ movptr(to,         to_arg);
     __ movl2ptr(length, length_arg);
     if (entry != NULL) {
       *entry = __ pc(); // Entry point from generic arraycopy stub.
       BLOCK_COMMENT("Entry:");
     }
     //---------------------------------------------------------------
     // Assembler stub will be used for this call to arraycopy
     // if the two arrays are subtypes of Object[] but the
     // destination array type is not equal to or a supertype
     // of the source type.  Each element must be separately
     // checked.
     // Loop-invariant addresses.  They are exclusive end pointers.
     Address end_from_addr(from, length, Address::times_ptr, 0);
     Address   end_to_addr(to,   length, Address::times_ptr, 0);
     Register end_from = from;           // re-use
     Register end_to   = to;             // re-use
     Register count    = length;         // re-use
     // Loop-variant addresses.  They assume post-incremented count < 0.
     Address from_element_addr(end_from, count, Address::times_ptr, 0);
     Address   to_element_addr(end_to,   count, Address::times_ptr, 0);
     Address elem_klass_addr(elem, oopDesc::klass_offset_in_bytes());
     // Copy from low to high addresses, indexed from the end of each array.
     gen_write_ref_array_pre_barrier(to, count, dest_uninitialized);
     __ lea(end_from, end_from_addr);
     __ lea(end_to,   end_to_addr);
     assert(length == count, "");        // else fix next line:
     __ negptr(count);                   // negate and test the length
     __ jccb(Assembler::notZero, L_load_element);
     // Empty array:  Nothing to do.
     __ xorptr(rax, rax);                  // return 0 on (trivial) success
     __ jmp(L_done);
     // ======== begin loop ========
     // (Loop is rotated; its entry is L_load_element.)
     // Loop control:
     //   for (count = -count; count != 0; count++)
     // Base pointers src, dst are biased by 8*count,to last element.
     __ align(OptoLoopAlignment);
     __ BIND(L_store_element);
     __ movptr(to_element_addr, elem);     // store the oop
     __ increment(count);                // increment the count toward zero
     __ jccb(Assembler::zero, L_do_card_marks);
     // ======== loop entry is here ========
     __ BIND(L_load_element);
     __ movptr(elem, from_element_addr);   // load the oop
     __ testptr(elem, elem);
     __ jccb(Assembler::zero, L_store_element);
     // (Could do a trick here:  Remember last successful non-null
     // element stored and make a quick oop equality check on it.)
     __ movptr(elem_klass, elem_klass_addr); // query the object klass
     generate_type_check(elem_klass, ckoff_arg, ckval_arg, temp,
                         &L_store_element, NULL);
       // (On fall-through, we have failed the element type check.)
     // ======== end loop ========
     // It was a real error; we must depend on the caller to finish the job.
     // Register "count" = -1 * number of *remaining* oops, length_arg = *total* oops.
     // Emit GC store barriers for the oops we have copied (length_arg + count),
     // and report their number to the caller.
     __ addl(count, length_arg);         // transfers = (length - remaining)
     __ movl2ptr(rax, count);            // save the value
     __ notptr(rax);                     // report (-1^K) to caller
     __ movptr(to, to_arg);              // reload
     assert_different_registers(to, count, rax);
     gen_write_ref_array_post_barrier(to, count);
     __ jmpb(L_done);
     // Come here on success only.
     __ BIND(L_do_card_marks);
     __ movl2ptr(count, length_arg);
     __ movptr(to, to_arg);                // reload
     gen_write_ref_array_post_barrier(to, count);
     __ xorptr(rax, rax);                  // return 0 on success
     // Common exit point (success or failure).
     __ BIND(L_done);
     __ pop(rbx);
     __ pop(rdi);
     __ pop(rsi);
     inc_counter_np(SharedRuntime::_checkcast_array_copy_ctr);
     __ leave(); // required for proper stackwalking of RuntimeStub frame
     __ ret(0);
     return start;
   }
   //
   //  Generate 'unsafe' array copy stub
   //  Though just as safe as the other stubs, it takes an unscaled
   //  size_t argument instead of an element count.
   //
   //  Input:
   //    4(rsp)   - source array address
   //    8(rsp)   - destination array address
   //   12(rsp)   - byte count, can be zero
   //
   //  Output:
   //    rax, ==  0  -  success
   //    rax, == -1  -  need to call System.arraycopy
   //
   // Examines the alignment of the operands and dispatches
   // to a long, int, short, or byte copy loop.
   //
   address generate_unsafe_copy(const char *name,
                                address byte_copy_entry,
                                address short_copy_entry,
                                address int_copy_entry,
                                address long_copy_entry) {
     Label L_long_aligned, L_int_aligned, L_short_aligned;
     __ align(CodeEntryAlignment);
     StubCodeMark mark(this, "StubRoutines", name);
     address start = __ pc();
     const Register from       = rax;  // source array address
     const Register to         = rdx;  // destination array address
     const Register count      = rcx;  // elements count
     __ enter(); // required for proper stackwalking of RuntimeStub frame
     __ push(rsi);
     __ push(rdi);
     Address  from_arg(rsp, 12+ 4);      // from
     Address    to_arg(rsp, 12+ 8);      // to
     Address count_arg(rsp, 12+12);      // byte count
     // Load up:
     __ movptr(from ,  from_arg);
     __ movptr(to   ,    to_arg);
     __ movl2ptr(count, count_arg);
     // bump this on entry, not on exit:
     inc_counter_np(SharedRuntime::_unsafe_array_copy_ctr);
     const Register bits = rsi;
     __ mov(bits, from);
     __ orptr(bits, to);
     __ orptr(bits, count);
     __ testl(bits, BytesPerLong-1);
     __ jccb(Assembler::zero, L_long_aligned);
     __ testl(bits, BytesPerInt-1);
     __ jccb(Assembler::zero, L_int_aligned);
     __ testl(bits, BytesPerShort-1);
     __ jump_cc(Assembler::notZero, RuntimeAddress(byte_copy_entry));
     __ BIND(L_short_aligned);
     __ shrptr(count, LogBytesPerShort); // size => short_count
     __ movl(count_arg, count);          // update 'count'
     __ jump(RuntimeAddress(short_copy_entry));
     __ BIND(L_int_aligned);
     __ shrptr(count, LogBytesPerInt); // size => int_count
     __ movl(count_arg, count);          // update 'count'
     __ jump(RuntimeAddress(int_copy_entry));
     __ BIND(L_long_aligned);
     __ shrptr(count, LogBytesPerLong); // size => qword_count
     __ movl(count_arg, count);          // update 'count'
     __ pop(rdi); // Do pops here since jlong_arraycopy stub does not do it.
     __ pop(rsi);
     __ jump(RuntimeAddress(long_copy_entry));
     return start;
   }
   // Perform range checks on the proposed arraycopy.
   // Smashes src_pos and dst_pos.  (Uses them up for temps.)
   void arraycopy_range_checks(Register src,
                               Register src_pos,
                               Register dst,
                               Register dst_pos,
                               Address& length,
                               Label& L_failed) {
     BLOCK_COMMENT("arraycopy_range_checks:");
     const Register src_end = src_pos;   // source array end position
     const Register dst_end = dst_pos;   // destination array end position
     __ addl(src_end, length); // src_pos + length
     __ addl(dst_end, length); // dst_pos + length
     //  if (src_pos + length > arrayOop(src)->length() ) FAIL;
     __ cmpl(src_end, Address(src, arrayOopDesc::length_offset_in_bytes()));
     __ jcc(Assembler::above, L_failed);
     //  if (dst_pos + length > arrayOop(dst)->length() ) FAIL;
     __ cmpl(dst_end, Address(dst, arrayOopDesc::length_offset_in_bytes()));
     __ jcc(Assembler::above, L_failed);
     BLOCK_COMMENT("arraycopy_range_checks done");
   }
   //
   //  Generate generic array copy stubs
   //
   //  Input:
   //     4(rsp)    -  src oop
   //     8(rsp)    -  src_pos
   //    12(rsp)    -  dst oop
   //    16(rsp)    -  dst_pos
   //    20(rsp)    -  element count
   //
   //  Output:
   //    rax, ==  0  -  success
   //    rax, == -1^K - failure, where K is partial transfer count
   //
   address generate_generic_copy(const char *name,
                                 address entry_jbyte_arraycopy,
                                 address entry_jshort_arraycopy,
                                 address entry_jint_arraycopy,
                                 address entry_oop_arraycopy,
                                 address entry_jlong_arraycopy,
                                 address entry_checkcast_arraycopy) {
     Label L_failed, L_failed_0, L_objArray;
     { int modulus = CodeEntryAlignment;
       int target  = modulus - 5; // 5 = sizeof jmp(L_failed)
       int advance = target - (__ offset() % modulus);
       if (advance < 0)  advance += modulus;
       if (advance > 0)  __ nop(advance);
     }
     StubCodeMark mark(this, "StubRoutines", name);
     // Short-hop target to L_failed.  Makes for denser prologue code.
     __ BIND(L_failed_0);
     __ jmp(L_failed);
     assert(__ offset() % CodeEntryAlignment == 0, "no further alignment needed");
     __ align(CodeEntryAlignment);
     address start = __ pc();
     __ enter(); // required for proper stackwalking of RuntimeStub frame
     __ push(rsi);
     __ push(rdi);
     // bump this on entry, not on exit:
     inc_counter_np(SharedRuntime::_generic_array_copy_ctr);
     // Input values
     Address SRC     (rsp, 12+ 4);
     Address SRC_POS (rsp, 12+ 8);
     Address DST     (rsp, 12+12);
     Address DST_POS (rsp, 12+16);
     Address LENGTH  (rsp, 12+20);
     //-----------------------------------------------------------------------
     // Assembler stub will be used for this call to arraycopy
     // if the following conditions are met:
     //
     // (1) src and dst must not be null.
     // (2) src_pos must not be negative.
     // (3) dst_pos must not be negative.
     // (4) length  must not be negative.
     // (5) src klass and dst klass should be the same and not NULL.
     // (6) src and dst should be arrays.
     // (7) src_pos + length must not exceed length of src.
     // (8) dst_pos + length must not exceed length of dst.
     //
     const Register src     = rax;       // source array oop
     const Register src_pos = rsi;
     const Register dst     = rdx;       // destination array oop
     const Register dst_pos = rdi;
     const Register length  = rcx;       // transfer count
     //  if (src == NULL) return -1;
     __ movptr(src, SRC);      // src oop
     __ testptr(src, src);
     __ jccb(Assembler::zero, L_failed_0);
     //  if (src_pos < 0) return -1;
     __ movl2ptr(src_pos, SRC_POS);  // src_pos
     __ testl(src_pos, src_pos);
     __ jccb(Assembler::negative, L_failed_0);
     //  if (dst == NULL) return -1;
     __ movptr(dst, DST);      // dst oop
     __ testptr(dst, dst);
     __ jccb(Assembler::zero, L_failed_0);
     //  if (dst_pos < 0) return -1;
     __ movl2ptr(dst_pos, DST_POS);  // dst_pos
     __ testl(dst_pos, dst_pos);
     __ jccb(Assembler::negative, L_failed_0);
     //  if (length < 0) return -1;
     __ movl2ptr(length, LENGTH);   // length
     __ testl(length, length);
     __ jccb(Assembler::negative, L_failed_0);
     //  if (src->klass() == NULL) return -1;
     Address src_klass_addr(src, oopDesc::klass_offset_in_bytes());
     Address dst_klass_addr(dst, oopDesc::klass_offset_in_bytes());
     const Register rcx_src_klass = rcx;    // array klass
     __ movptr(rcx_src_klass, Address(src, oopDesc::klass_offset_in_bytes()));
 #ifdef ASSERT
     //  assert(src->klass() != NULL);
     BLOCK_COMMENT("assert klasses not null");
     { Label L1, L2;
       __ testptr(rcx_src_klass, rcx_src_klass);
       __ jccb(Assembler::notZero, L2);   // it is broken if klass is NULL
       __ bind(L1);
       __ stop("broken null klass");
       __ bind(L2);
       __ cmpptr(dst_klass_addr, (int32_t)NULL_WORD);
       __ jccb(Assembler::equal, L1);      // this would be broken also
       BLOCK_COMMENT("assert done");
     }
 #endif //ASSERT
     // Load layout helper (32-bits)
     //
     //  |array_tag|     | header_size | element_type |     |log2_element_size|
     // 32        30    24            16              8     2                 0
     //
     //   array_tag: typeArray = 0x3, objArray = 0x2, non-array = 0x0
     //
     int lh_offset = klassOopDesc::header_size() * HeapWordSize +
                     Klass::layout_helper_offset_in_bytes();
     Address src_klass_lh_addr(rcx_src_klass, lh_offset);
     // Handle objArrays completely differently...
     jint objArray_lh = Klass::array_layout_helper(T_OBJECT);
     __ cmpl(src_klass_lh_addr, objArray_lh);
     __ jcc(Assembler::equal, L_objArray);
     //  if (src->klass() != dst->klass()) return -1;
     __ cmpptr(rcx_src_klass, dst_klass_addr);
     __ jccb(Assembler::notEqual, L_failed_0);
     const Register rcx_lh = rcx;  // layout helper
     assert(rcx_lh == rcx_src_klass, "known alias");
     __ movl(rcx_lh, src_klass_lh_addr);
     //  if (!src->is_Array()) return -1;
     __ cmpl(rcx_lh, Klass::_lh_neutral_value);
     __ jcc(Assembler::greaterEqual, L_failed_0); // signed cmp
     // At this point, it is known to be a typeArray (array_tag 0x3).
 #ifdef ASSERT
     { Label L;
       __ cmpl(rcx_lh, (Klass::_lh_array_tag_type_value << Klass::_lh_array_tag_shift));
       __ jcc(Assembler::greaterEqual, L); // signed cmp
       __ stop("must be a primitive array");
       __ bind(L);
     }
 #endif
     assert_different_registers(src, src_pos, dst, dst_pos, rcx_lh);
     arraycopy_range_checks(src, src_pos, dst, dst_pos, LENGTH, L_failed);
     // typeArrayKlass
     //
     // src_addr = (src + array_header_in_bytes()) + (src_pos << log2elemsize);
     // dst_addr = (dst + array_header_in_bytes()) + (dst_pos << log2elemsize);
     //
     const Register rsi_offset = rsi; // array offset
     const Register src_array  = src; // src array offset
     const Register dst_array  = dst; // dst array offset
     const Register rdi_elsize = rdi; // log2 element size
     __ mov(rsi_offset, rcx_lh);
     __ shrptr(rsi_offset, Klass::_lh_header_size_shift);
     __ andptr(rsi_offset, Klass::_lh_header_size_mask);   // array_offset
     __ addptr(src_array, rsi_offset);  // src array offset
     __ addptr(dst_array, rsi_offset);  // dst array offset
     __ andptr(rcx_lh, Klass::_lh_log2_element_size_mask); // log2 elsize
     // next registers should be set before the jump to corresponding stub
     const Register from       = src; // source array address
     const Register to         = dst; // destination array address
     const Register count      = rcx; // elements count
     // some of them should be duplicated on stack
 #define FROM   Address(rsp, 12+ 4)
 #define TO     Address(rsp, 12+ 8)   // Not used now
 #define COUNT  Address(rsp, 12+12)   // Only for oop arraycopy
     BLOCK_COMMENT("scale indexes to element size");
     __ movl2ptr(rsi, SRC_POS);  // src_pos
     __ shlptr(rsi);             // src_pos << rcx (log2 elsize)
     assert(src_array == from, "");
     __ addptr(from, rsi);       // from = src_array + SRC_POS << log2 elsize
     __ movl2ptr(rdi, DST_POS);  // dst_pos
     __ shlptr(rdi);             // dst_pos << rcx (log2 elsize)
     assert(dst_array == to, "");
     __ addptr(to,  rdi);        // to   = dst_array + DST_POS << log2 elsize
     __ movptr(FROM, from);      // src_addr
     __ mov(rdi_elsize, rcx_lh); // log2 elsize
     __ movl2ptr(count, LENGTH); // elements count
     BLOCK_COMMENT("choose copy loop based on element size");
     __ cmpl(rdi_elsize, 0);
     __ jump_cc(Assembler::equal, RuntimeAddress(entry_jbyte_arraycopy));
     __ cmpl(rdi_elsize, LogBytesPerShort);
     __ jump_cc(Assembler::equal, RuntimeAddress(entry_jshort_arraycopy));
     __ cmpl(rdi_elsize, LogBytesPerInt);
     __ jump_cc(Assembler::equal, RuntimeAddress(entry_jint_arraycopy));
 #ifdef ASSERT
     __ cmpl(rdi_elsize, LogBytesPerLong);
     __ jccb(Assembler::notEqual, L_failed);
 #endif
     __ pop(rdi); // Do pops here since jlong_arraycopy stub does not do it.
     __ pop(rsi);
     __ jump(RuntimeAddress(entry_jlong_arraycopy));
   __ BIND(L_failed);
     __ xorptr(rax, rax);
     __ notptr(rax); // return -1
     __ pop(rdi);
     __ pop(rsi);
     __ leave(); // required for proper stackwalking of RuntimeStub frame
     __ ret(0);
     // objArrayKlass
   __ BIND(L_objArray);
     // live at this point:  rcx_src_klass, src[_pos], dst[_pos]
     Label L_plain_copy, L_checkcast_copy;
     //  test array classes for subtyping
     __ cmpptr(rcx_src_klass, dst_klass_addr); // usual case is exact equality
     __ jccb(Assembler::notEqual, L_checkcast_copy);
     // Identically typed arrays can be copied without element-wise checks.
     assert_different_registers(src, src_pos, dst, dst_pos, rcx_src_klass);
     arraycopy_range_checks(src, src_pos, dst, dst_pos, LENGTH, L_failed);
   __ BIND(L_plain_copy);
     __ movl2ptr(count, LENGTH); // elements count
     __ movl2ptr(src_pos, SRC_POS);  // reload src_pos
     __ lea(from, Address(src, src_pos, Address::times_ptr,
                  arrayOopDesc::base_offset_in_bytes(T_OBJECT))); // src_addr
     __ movl2ptr(dst_pos, DST_POS);  // reload dst_pos
     __ lea(to,   Address(dst, dst_pos, Address::times_ptr,
                  arrayOopDesc::base_offset_in_bytes(T_OBJECT))); // dst_addr
     __ movptr(FROM,  from);   // src_addr
     __ movptr(TO,    to);     // dst_addr
     __ movl(COUNT, count);  // count
     __ jump(RuntimeAddress(entry_oop_arraycopy));
   __ BIND(L_checkcast_copy);
     // live at this point:  rcx_src_klass, dst[_pos], src[_pos]
     {
       // Handy offsets:
       int  ek_offset = (klassOopDesc::header_size() * HeapWordSize +
                         objArrayKlass::element_klass_offset_in_bytes());
       int sco_offset = (klassOopDesc::header_size() * HeapWordSize +
                         Klass::super_check_offset_offset_in_bytes());
       Register rsi_dst_klass = rsi;
       Register rdi_temp      = rdi;
       assert(rsi_dst_klass == src_pos, "expected alias w/ src_pos");
       assert(rdi_temp      == dst_pos, "expected alias w/ dst_pos");
       Address dst_klass_lh_addr(rsi_dst_klass, lh_offset);
       // Before looking at dst.length, make sure dst is also an objArray.
       __ movptr(rsi_dst_klass, dst_klass_addr);
       __ cmpl(dst_klass_lh_addr, objArray_lh);
       __ jccb(Assembler::notEqual, L_failed);
       // It is safe to examine both src.length and dst.length.
       __ movl2ptr(src_pos, SRC_POS);        // reload rsi
       arraycopy_range_checks(src, src_pos, dst, dst_pos, LENGTH, L_failed);
       // (Now src_pos and dst_pos are killed, but not src and dst.)
       // We'll need this temp (don't forget to pop it after the type check).
       __ push(rbx);
       Register rbx_src_klass = rbx;
       __ mov(rbx_src_klass, rcx_src_klass); // spill away from rcx
       __ movptr(rsi_dst_klass, dst_klass_addr);
       Address super_check_offset_addr(rsi_dst_klass, sco_offset);
       Label L_fail_array_check;
       generate_type_check(rbx_src_klass,
                           super_check_offset_addr, dst_klass_addr,
                           rdi_temp, NULL, &L_fail_array_check);
       // (On fall-through, we have passed the array type check.)
       __ pop(rbx);
       __ jmp(L_plain_copy);
       __ BIND(L_fail_array_check);
       // Reshuffle arguments so we can call checkcast_arraycopy:
       // match initial saves for checkcast_arraycopy
       // push(rsi);    // already done; see above
       // push(rdi);    // already done; see above
       // push(rbx);    // already done; see above
       // Marshal outgoing arguments now, freeing registers.
       Address   from_arg(rsp, 16+ 4);   // from
       Address     to_arg(rsp, 16+ 8);   // to
       Address length_arg(rsp, 16+12);   // elements count
       Address  ckoff_arg(rsp, 16+16);   // super_check_offset
       Address  ckval_arg(rsp, 16+20);   // super_klass
       Address SRC_POS_arg(rsp, 16+ 8);
       Address DST_POS_arg(rsp, 16+16);
       Address  LENGTH_arg(rsp, 16+20);
       // push rbx, changed the incoming offsets (why not just use rbp,??)
       // assert(SRC_POS_arg.disp() == SRC_POS.disp() + 4, "");
       __ movptr(rbx, Address(rsi_dst_klass, ek_offset));
       __ movl2ptr(length, LENGTH_arg);    // reload elements count
       __ movl2ptr(src_pos, SRC_POS_arg);  // reload src_pos
       __ movl2ptr(dst_pos, DST_POS_arg);  // reload dst_pos
       __ movptr(ckval_arg, rbx);          // destination element type
       __ movl(rbx, Address(rbx, sco_offset));
       __ movl(ckoff_arg, rbx);          // corresponding class check offset
       __ movl(length_arg, length);      // outgoing length argument
       __ lea(from, Address(src, src_pos, Address::times_ptr,
                             arrayOopDesc::base_offset_in_bytes(T_OBJECT)));
       __ movptr(from_arg, from);
       __ lea(to, Address(dst, dst_pos, Address::times_ptr,
                           arrayOopDesc::base_offset_in_bytes(T_OBJECT)));
       __ movptr(to_arg, to);
       __ jump(RuntimeAddress(entry_checkcast_arraycopy));
     }
     return start;
   }
   void generate_arraycopy_stubs() {
     address entry;
     address entry_jbyte_arraycopy;
     address entry_jshort_arraycopy;
     address entry_jint_arraycopy;
     address entry_oop_arraycopy;
     address entry_jlong_arraycopy;
     address entry_checkcast_arraycopy;
     StubRoutines::_arrayof_jbyte_disjoint_arraycopy =
         generate_disjoint_copy(T_BYTE,  true, Address::times_1, &entry,
                                "arrayof_jbyte_disjoint_arraycopy");
     StubRoutines::_arrayof_jbyte_arraycopy =
         generate_conjoint_copy(T_BYTE,  true, Address::times_1,  entry,
                                NULL, "arrayof_jbyte_arraycopy");
     StubRoutines::_jbyte_disjoint_arraycopy =
         generate_disjoint_copy(T_BYTE, false, Address::times_1, &entry,
                                "jbyte_disjoint_arraycopy");
     StubRoutines::_jbyte_arraycopy =
         generate_conjoint_copy(T_BYTE, false, Address::times_1,  entry,
                                &entry_jbyte_arraycopy, "jbyte_arraycopy");
     StubRoutines::_arrayof_jshort_disjoint_arraycopy =
         generate_disjoint_copy(T_SHORT,  true, Address::times_2, &entry,
                                "arrayof_jshort_disjoint_arraycopy");
     StubRoutines::_arrayof_jshort_arraycopy =
         generate_conjoint_copy(T_SHORT,  true, Address::times_2,  entry,
                                NULL, "arrayof_jshort_arraycopy");
     StubRoutines::_jshort_disjoint_arraycopy =
         generate_disjoint_copy(T_SHORT, false, Address::times_2, &entry,
                                "jshort_disjoint_arraycopy");
     StubRoutines::_jshort_arraycopy =
         generate_conjoint_copy(T_SHORT, false, Address::times_2,  entry,
                                &entry_jshort_arraycopy, "jshort_arraycopy");
     // Next arrays are always aligned on 4 bytes at least.
     StubRoutines::_jint_disjoint_arraycopy =
         generate_disjoint_copy(T_INT, true, Address::times_4, &entry,
                                "jint_disjoint_arraycopy");
     StubRoutines::_jint_arraycopy =
         generate_conjoint_copy(T_INT, true, Address::times_4,  entry,
                                &entry_jint_arraycopy, "jint_arraycopy");
     StubRoutines::_oop_disjoint_arraycopy =
         generate_disjoint_copy(T_OBJECT, true, Address::times_ptr, &entry,
                                "oop_disjoint_arraycopy");
     StubRoutines::_oop_arraycopy =
         generate_conjoint_copy(T_OBJECT, true, Address::times_ptr,  entry,
                                &entry_oop_arraycopy, "oop_arraycopy");
     StubRoutines::_oop_disjoint_arraycopy_uninit =
         generate_disjoint_copy(T_OBJECT, true, Address::times_ptr, &entry,
                                "oop_disjoint_arraycopy_uninit",
                                /*dest_uninitialized*/true);
     StubRoutines::_oop_arraycopy_uninit =
         generate_conjoint_copy(T_OBJECT, true, Address::times_ptr,  entry,
                                NULL, "oop_arraycopy_uninit",
                                /*dest_uninitialized*/true);
     StubRoutines::_jlong_disjoint_arraycopy =
         generate_disjoint_long_copy(&entry, "jlong_disjoint_arraycopy");
     StubRoutines::_jlong_arraycopy =
         generate_conjoint_long_copy(entry, &entry_jlong_arraycopy,
                                     "jlong_arraycopy");
     StubRoutines::_jbyte_fill = generate_fill(T_BYTE, false, "jbyte_fill");
     StubRoutines::_jshort_fill = generate_fill(T_SHORT, false, "jshort_fill");
     StubRoutines::_jint_fill = generate_fill(T_INT, false, "jint_fill");
     StubRoutines::_arrayof_jbyte_fill = generate_fill(T_BYTE, true, "arrayof_jbyte_fill");
     StubRoutines::_arrayof_jshort_fill = generate_fill(T_SHORT, true, "arrayof_jshort_fill");
     StubRoutines::_arrayof_jint_fill = generate_fill(T_INT, true, "arrayof_jint_fill");
     StubRoutines::_arrayof_jint_disjoint_arraycopy       = StubRoutines::_jint_disjoint_arraycopy;
     StubRoutines::_arrayof_oop_disjoint_arraycopy        = StubRoutines::_oop_disjoint_arraycopy;
     StubRoutines::_arrayof_oop_disjoint_arraycopy_uninit = StubRoutines::_oop_disjoint_arraycopy_uninit;
     StubRoutines::_arrayof_jlong_disjoint_arraycopy      = StubRoutines::_jlong_disjoint_arraycopy;
     StubRoutines::_arrayof_jint_arraycopy       = StubRoutines::_jint_arraycopy;
     StubRoutines::_arrayof_oop_arraycopy        = StubRoutines::_oop_arraycopy;
     StubRoutines::_arrayof_oop_arraycopy_uninit = StubRoutines::_oop_arraycopy_uninit;
     StubRoutines::_arrayof_jlong_arraycopy      = StubRoutines::_jlong_arraycopy;
     StubRoutines::_checkcast_arraycopy =
         generate_checkcast_copy("checkcast_arraycopy", &entry_checkcast_arraycopy);
     StubRoutines::_checkcast_arraycopy_uninit =
         generate_checkcast_copy("checkcast_arraycopy_uninit", NULL, /*dest_uninitialized*/true);
     StubRoutines::_unsafe_arraycopy =
         generate_unsafe_copy("unsafe_arraycopy",
                                entry_jbyte_arraycopy,
                                entry_jshort_arraycopy,
                                entry_jint_arraycopy,
                                entry_jlong_arraycopy);
     StubRoutines::_generic_arraycopy =
         generate_generic_copy("generic_arraycopy",
                                entry_jbyte_arraycopy,
                                entry_jshort_arraycopy,
                                entry_jint_arraycopy,
                                entry_oop_arraycopy,
                                entry_jlong_arraycopy,
                                entry_checkcast_arraycopy);
   }
   void generate_math_stubs() {
     {
       StubCodeMark mark(this, "StubRoutines", "log");
       StubRoutines::_intrinsic_log = (double (*)(double)) __ pc();
       __ fld_d(Address(rsp, 4));
       __ flog();
       __ ret(0);
     }
     {
       StubCodeMark mark(this, "StubRoutines", "log10");
       StubRoutines::_intrinsic_log10 = (double (*)(double)) __ pc();
       __ fld_d(Address(rsp, 4));
       __ flog10();
       __ ret(0);
     }
     {
       StubCodeMark mark(this, "StubRoutines", "sin");
       StubRoutines::_intrinsic_sin = (double (*)(double))  __ pc();
       __ fld_d(Address(rsp, 4));
       __ trigfunc('s');
       __ ret(0);
     }
     {
       StubCodeMark mark(this, "StubRoutines", "cos");
       StubRoutines::_intrinsic_cos = (double (*)(double)) __ pc();
       __ fld_d(Address(rsp, 4));
       __ trigfunc('c');
       __ ret(0);
     }
     {
       StubCodeMark mark(this, "StubRoutines", "tan");
       StubRoutines::_intrinsic_tan = (double (*)(double)) __ pc();
       __ fld_d(Address(rsp, 4));
       __ trigfunc('t');
       __ ret(0);
     }
     // The intrinsic version of these seem to return the same value as
     // the strict version.
     StubRoutines::_intrinsic_exp = SharedRuntime::dexp;
     StubRoutines::_intrinsic_pow = SharedRuntime::dpow;
   }
  public:
   // Information about frame layout at time of blocking runtime call.
   // Note that we only have to preserve callee-saved registers since
   // the compilers are responsible for supplying a continuation point
   // if they expect all registers to be preserved.
   enum layout {
     thread_off,    // last_java_sp
     arg1_off,
     arg2_off,
     rbp_off,       // callee saved register
     ret_pc,
     framesize
   };
  private:
 #undef  __
 #define __ masm->
   //------------------------------------------------------------------------------------------------------------------------
   // Continuation point for throwing of implicit exceptions that are not handled in
   // the current activation. Fabricates an exception oop and initiates normal
   // exception dispatching in this frame.
   //
   // Previously the compiler (c2) allowed for callee save registers on Java calls.
   // This is no longer true after adapter frames were removed but could possibly
   // be brought back in the future if the interpreter code was reworked and it
   // was deemed worthwhile. The comment below was left to describe what must
   // happen here if callee saves were resurrected. As it stands now this stub
   // could actually be a vanilla BufferBlob and have now oopMap at all.
   // Since it doesn't make much difference we've chosen to leave it the
   // way it was in the callee save days and keep the comment.
   // If we need to preserve callee-saved values we need a callee-saved oop map and
   // therefore have to make these stubs into RuntimeStubs rather than BufferBlobs.
   // If the compiler needs all registers to be preserved between the fault
   // point and the exception handler then it must assume responsibility for that in
   // AbstractCompiler::continuation_for_implicit_null_exception or
   // continuation_for_implicit_division_by_zero_exception. All other implicit
   // exceptions (e.g., NullPointerException or AbstractMethodError on entry) are
   // either at call sites or otherwise assume that stack unwinding will be initiated,
   // so caller saved registers were assumed volatile in the compiler.
   address generate_throw_exception(const char* name, address runtime_entry,
                                    Register arg1 = noreg, Register arg2 = noreg) {
     int insts_size = 256;
     int locs_size  = 32;
     CodeBuffer code(name, insts_size, locs_size);
     OopMapSet* oop_maps  = new OopMapSet();
     MacroAssembler* masm = new MacroAssembler(&code);
     address start = __ pc();
     // This is an inlined and slightly modified version of call_VM
     // which has the ability to fetch the return PC out of
     // thread-local storage and also sets up last_Java_sp slightly
     // differently than the real call_VM
     Register java_thread = rbx;
     __ get_thread(java_thread);
     __ enter(); // required for proper stackwalking of RuntimeStub frame
     // pc and rbp, already pushed
     __ subptr(rsp, (framesize-2) * wordSize); // prolog
     // Frame is now completed as far as size and linkage.
     int frame_complete = __ pc() - start;
     // push java thread (becomes first argument of C function)
     __ movptr(Address(rsp, thread_off * wordSize), java_thread);
     if (arg1 != noreg) {
       __ movptr(Address(rsp, arg1_off * wordSize), arg1);
     }
     if (arg2 != noreg) {
       assert(arg1 != noreg, "missing reg arg");
       __ movptr(Address(rsp, arg2_off * wordSize), arg2);
     }
     // Set up last_Java_sp and last_Java_fp
     __ set_last_Java_frame(java_thread, rsp, rbp, NULL);
     // Call runtime
     BLOCK_COMMENT("call runtime_entry");
     __ call(RuntimeAddress(runtime_entry));
     // Generate oop map
     OopMap* map =  new OopMap(framesize, 0);
     oop_maps->add_gc_map(__ pc() - start, map);
     // restore the thread (cannot use the pushed argument since arguments
     // may be overwritten by C code generated by an optimizing compiler);
     // however can use the register value directly if it is callee saved.
     __ get_thread(java_thread);
     __ reset_last_Java_frame(java_thread, true, false);
     __ leave(); // required for proper stackwalking of RuntimeStub frame
     // check for pending exceptions
 #ifdef ASSERT
     Label L;
     __ cmpptr(Address(java_thread, Thread::pending_exception_offset()), (int32_t)NULL_WORD);
     __ jcc(Assembler::notEqual, L);
     __ should_not_reach_here();
     __ bind(L);
 #endif /* ASSERT */
     __ jump(RuntimeAddress(StubRoutines::forward_exception_entry()));
     RuntimeStub* stub = RuntimeStub::new_runtime_stub(name, &code, frame_complete, framesize, oop_maps, false);
     return stub->entry_point();
   }
   void create_control_words() {
     // Round to nearest, 53-bit mode, exceptions masked
     StubRoutines::_fpu_cntrl_wrd_std   = 0x027F;
     // Round to zero, 53-bit mode, exception mased
     StubRoutines::_fpu_cntrl_wrd_trunc = 0x0D7F;
     // Round to nearest, 24-bit mode, exceptions masked
     StubRoutines::_fpu_cntrl_wrd_24    = 0x007F;
     // Round to nearest, 64-bit mode, exceptions masked
     StubRoutines::_fpu_cntrl_wrd_64    = 0x037F;
     // Round to nearest, 64-bit mode, exceptions masked
     StubRoutines::_mxcsr_std           = 0x1F80;
     // Note: the following two constants are 80-bit values
     //       layout is critical for correct loading by FPU.
     // Bias for strict fp multiply/divide
     StubRoutines::_fpu_subnormal_bias1[0]= 0x00000000; // 2^(-15360) == 0x03ff 8000 0000 0000 0000
     StubRoutines::_fpu_subnormal_bias1[1]= 0x80000000;
     StubRoutines::_fpu_subnormal_bias1[2]= 0x03ff;
     // Un-Bias for strict fp multiply/divide
     StubRoutines::_fpu_subnormal_bias2[0]= 0x00000000; // 2^(+15360) == 0x7bff 8000 0000 0000 0000
     StubRoutines::_fpu_subnormal_bias2[1]= 0x80000000;
     StubRoutines::_fpu_subnormal_bias2[2]= 0x7bff;
   }
   //---------------------------------------------------------------------------
   // Initialization
   void generate_initial() {
     // Generates all stubs and initializes the entry points
     //------------------------------------------------------------------------------------------------------------------------
     // entry points that exist in all platforms
     // Note: This is code that could be shared among different platforms - however the benefit seems to be smaller than
     //       the disadvantage of having a much more complicated generator structure. See also comment in stubRoutines.hpp.
     StubRoutines::_forward_exception_entry      = generate_forward_exception();
     StubRoutines::_call_stub_entry              =
       generate_call_stub(StubRoutines::_call_stub_return_address);
     // is referenced by megamorphic call
     StubRoutines::_catch_exception_entry        = generate_catch_exception();
     // These are currently used by Solaris/Intel
     StubRoutines::_atomic_xchg_entry            = generate_atomic_xchg();
     StubRoutines::_handler_for_unsafe_access_entry =
       generate_handler_for_unsafe_access();
     // platform dependent
     create_control_words();
     StubRoutines::x86::_verify_mxcsr_entry                 = generate_verify_mxcsr();
     StubRoutines::x86::_verify_fpu_cntrl_wrd_entry         = generate_verify_fpu_cntrl_wrd();
     StubRoutines::_d2i_wrapper                              = generate_d2i_wrapper(T_INT,
                                                                                    CAST_FROM_FN_PTR(address, SharedRuntime::d2i));
     StubRoutines::_d2l_wrapper                              = generate_d2i_wrapper(T_LONG,
                                                                                    CAST_FROM_FN_PTR(address, SharedRuntime::d2l));
     // Build this early so it's available for the interpreter
     StubRoutines::_throw_WrongMethodTypeException_entry =
       generate_throw_exception("WrongMethodTypeException throw_exception",
                                CAST_FROM_FN_PTR(address, SharedRuntime::throw_WrongMethodTypeException),
                                rax, rcx);
     // Build this early so it's available for the interpreter
     StubRoutines::_throw_StackOverflowError_entry          = generate_throw_exception("StackOverflowError throw_exception",           CAST_FROM_FN_PTR(address, SharedRuntime::throw_StackOverflowError));
   }
   void generate_all() {
     // Generates all stubs and initializes the entry points
     // These entry points require SharedInfo::stack0 to be set up in non-core builds
     // and need to be relocatable, so they each fabricate a RuntimeStub internally.
     StubRoutines::_throw_AbstractMethodError_entry         = generate_throw_exception("AbstractMethodError throw_exception",          CAST_FROM_FN_PTR(address, SharedRuntime::throw_AbstractMethodError));
     StubRoutines::_throw_IncompatibleClassChangeError_entry= generate_throw_exception("IncompatibleClassChangeError throw_exception", CAST_FROM_FN_PTR(address, SharedRuntime::throw_IncompatibleClassChangeError));
     StubRoutines::_throw_NullPointerException_at_call_entry= generate_throw_exception("NullPointerException at call throw_exception", CAST_FROM_FN_PTR(address, SharedRuntime::throw_NullPointerException_at_call));
     //------------------------------------------------------------------------------------------------------------------------
     // entry points that are platform specific
     // support for verify_oop (must happen after universe_init)
     StubRoutines::_verify_oop_subroutine_entry     = generate_verify_oop();
     // arraycopy stubs used by compilers
     generate_arraycopy_stubs();
     generate_math_stubs();
   }
  public:
   StubGenerator(CodeBuffer* code, bool all) : StubCodeGenerator(code) {
     if (all) {
       generate_all();
     } else {
       generate_initial();
     }
   }
 }; // end class declaration
 void StubGenerator_generate(CodeBuffer* code, bool all) {
   StubGenerator g(code, all);
 }

Mercurial > jdk8-mips64-public > hotspot / annotate

src/cpu/x86/vm/stubGenerator_x86_32.cpp@dca455dea3a7 (annotated)

src/cpu/x86/vm/stubGenerator_x86_32.cpp