/* * Copyright (c) 2016, 2021, Oracle and/or its affiliates. All rights reserved. * Copyright (c) 2016 SAP SE. 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. *
*/
//------------------------------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 s390.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 branch. // // Arguments: // Z_R2(=Z_ARG1): exception oop // Z_R3(=Z_ARG2): exception pc // // Results: // Z_R2: exception oop // Z_R3: exception pc in caller // 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 the code
ResourceMark rm; // Setup code generation tools
CodeBuffer buffer("exception_blob", 2048, 1024);
MacroAssembler* masm = new MacroAssembler(&buffer);
// Store issuing pc as return pc into // caller's frame. stack-walking needs it. R14 is not valid here, // because this code gets entered with a jump.
__ z_stg(Z_ARG2/*issuing pc*/, _z_abi(return_pc), Z_SP);
// The following call to function OptoRuntime::handle_exception_C // 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's // unpack_with_exception entry.
// push a C frame for the exception blob. it is needed for the // C call later on.
Register saved_sp = Z_R11;
__ z_lgr(saved_sp, Z_SP);
// push frame for blob. int frame_size = __ push_frame_abi160(0);
// This call can lead to deoptimization of the nmethod holding the handler.
__ z_lgr(Z_ARG1, Z_thread); // argument of C function
__ call_c(CAST_FROM_FN_PTR(address, OptoRuntime::handle_exception_C));
// Pop the exception blob's C frame that has been pushed before.
__ z_lgr(Z_SP, saved_sp);
// [Z_RET]!=NULL was possible in hotspot5 but not in sapjvm6. // C2I adapter extensions are now removed by a resize in the frame manager // (unwind_initial_activation_pending_exception). #ifdef ASSERT
__ z_ltgr(handle_exception, handle_exception);
__ asm_assert_ne("handler must not be NULL", 0x852); #endif
// Handle_exception contains the handler address. If the associated frame // has been deoptimized then the handler has been patched to jump to // the deoptimization blob.
// If the exception handler jumps to the deoptimization blob, the // exception pc will be read from there.
__ z_lg(Z_ARG2, Address(Z_thread, JavaThread::exception_pc_offset()));
// Clear the exception oop so GC no longer processes it as a root.
__ clear_mem(Address(Z_thread, JavaThread::exception_oop_offset()),sizeof(intptr_t)); #ifdef ASSERT
__ clear_mem(Address(Z_thread, JavaThread::exception_handler_pc_offset()), sizeof(intptr_t));
__ clear_mem(Address(Z_thread, JavaThread::exception_pc_offset()), sizeof(intptr_t)); #endif
__ z_br(handle_exception);
// Make sure all code is generated.
masm->flush();
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