/*

 * Copyright (c) 1998, 2010, 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.

 *

 */

#define __ masm->

ExceptionBlob      *OptoRuntime::_exception_blob;

//------------------------------ generate_exception_blob ---------------------------

// creates exception blob at the end

// Using exception blob, this code is jumped from a compiled method.

// (see emit_exception_handler in sparc.ad file)

//

// Given an exception pc at a call we call into the runtime for the

// handler in this method. This handler might merely restore state

// (i.e. callee save registers) unwind the frame and jump to the

// exception handler for the nmethod if there is no Java level handler

// for the nmethod.

//

// This code is entered with a jmp.

//

// Arguments:

//   O0: exception oop

//   O1: exception pc

//

// Results:

//   O0: exception oop

//   O1: exception pc in caller or ???

//   destination: exception handler of caller

//

// Note: the exception pc MUST be at a call (precise debug information)

//

void OptoRuntime::generate_exception_blob() {

  // allocate space for code

  ResourceMark rm;

  int pad = VerifyThread ? 256 : 0;// Extra slop space for more verify code

  // setup code generation tools

  // Measured 8/7/03 at 256 in 32bit debug build (no VerifyThread)

  // Measured 8/7/03 at 528 in 32bit debug build (VerifyThread)

  CodeBuffer buffer("exception_blob", 600+pad, 512);

  MacroAssembler* masm     = new MacroAssembler(&buffer);

  int framesize_in_bytes = __ total_frame_size_in_bytes(0);

  int framesize_in_words = framesize_in_bytes / wordSize;

  int framesize_in_slots = framesize_in_bytes / sizeof(jint);

  Label L;

  int start = __ offset();

  __ verify_thread();

  __ st_ptr(Oexception,  G2_thread, JavaThread::exception_oop_offset());

  __ st_ptr(Oissuing_pc, G2_thread, JavaThread::exception_pc_offset());

  // This call does all the hard work. It checks if an exception catch

  // exists in the method.

  // If so, it returns the handler address.

  // If the nmethod has been deoptimized and it had a handler the handler

  // address is the deopt blob unpack_with_exception entry.

  //

  // If no handler exists it prepares for stack-unwinding, restoring the callee-save

  // registers of the frame being removed.

  //

  __ save_frame(0);

  __ mov(G2_thread, O0);

  __ set_last_Java_frame(SP, noreg);

  __ save_thread(L7_thread_cache);

  // This call can block at exit and nmethod can be deoptimized at that

  // point. If the nmethod had a catch point we would jump to the

  // now deoptimized catch point and fall thru the vanilla deopt

  // path and lose the exception

  // Sure would be simpler if this call didn't block!

  __ call(CAST_FROM_FN_PTR(address, OptoRuntime::handle_exception_C), relocInfo::runtime_call_type);

  __ delayed()->mov(L7_thread_cache, O0);

  // Set an oopmap for the call site.  This oopmap will only be used if we

  // are unwinding the stack.  Hence, all locations will be dead.

  // Callee-saved registers will be the same as the frame above (i.e.,

  // handle_exception_stub), since they were restored when we got the

  // exception.

  OopMapSet *oop_maps = new OopMapSet();

  oop_maps->add_gc_map( __ offset()-start, new OopMap(framesize_in_slots, 0));

  __ bind(L);

  __ restore_thread(L7_thread_cache);

  __ reset_last_Java_frame();

  __ mov(O0, G3_scratch);             // Move handler address to temp

  __ restore();

  // Restore SP from L7 if the exception PC is a MethodHandle call site.

  __ lduw(Address(G2_thread, JavaThread::is_method_handle_return_offset()), O7);

  __ tst(O7);

  __ movcc(Assembler::notZero, false, Assembler::icc, L7_mh_SP_save, SP);

  // G3_scratch contains handler address

  // Since this may be the deopt blob we must set O7 to look like we returned

  // from the original pc that threw the exception

  __ ld_ptr(G2_thread, JavaThread::exception_pc_offset(), O7);

  __ sub(O7, frame::pc_return_offset, O7);

  assert(Assembler::is_simm13(in_bytes(JavaThread::exception_oop_offset())), "exception offset overflows simm13, following ld instruction cannot be in delay slot");

  __ ld_ptr(G2_thread, JavaThread::exception_oop_offset(), Oexception); // O0

#ifdef ASSERT

  __ st_ptr(G0, G2_thread, JavaThread::exception_handler_pc_offset());

  __ st_ptr(G0, G2_thread, JavaThread::exception_pc_offset());

#endif

  __ JMP(G3_scratch, 0);

  // Clear the exception oop so GC no longer processes it as a root.

  __ delayed()->st_ptr(G0, G2_thread, JavaThread::exception_oop_offset());

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

  // make sure all code is generated

  masm->flush();

  _exception_blob = ExceptionBlob::create(&buffer, oop_maps, framesize_in_words);

}