/* * Copyright (c) 1998, 2021, Oracle and/or its affiliates. All rights reserved. * Copyright (c) 2012, 2018 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. // // 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: // R3_ARG1: exception oop // R4_ARG2: exception pc // // Results: // R3_ARG1: exception oop // R4_ARG2: 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);
InterpreterMacroAssembler* masm = new InterpreterMacroAssembler(&buffer);
address start = __ pc();
int frame_size_in_bytes = frame::abi_reg_args_size;
OopMap* map = new OopMap(frame_size_in_bytes / sizeof(jint), 0);
// Exception pc is 'return address' for stack walker.
__ std(R4_ARG2/*exception pc*/, _abi0(lr), R1_SP);
// Store the exception in the Thread object.
__ std(R3_ARG1/*exception oop*/, in_bytes(JavaThread::exception_oop_offset()), R16_thread);
__ std(R4_ARG2/*exception pc*/, in_bytes(JavaThread::exception_pc_offset()), R16_thread);
// Save callee-saved registers. // Push a C frame for the exception blob. It is needed for the C call later on.
__ push_frame_reg_args(0, R11_scratch1);
// This call does all the hard work. It checks if an exception handler // exists in the method. // If so, it returns the handler address. // If not, it prepares for stack-unwinding, restoring the callee-save // registers of the frame being removed.
__ set_last_Java_frame(/*sp=*/R1_SP, noreg);
// 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(calls_return_pc - start, map);
__ mtctr(R3_RET); // Move address of exception handler to SR_CTR.
__ reset_last_Java_frame();
__ pop_frame();
// We have a handler in register SR_CTR (could be deopt blob).
// Get the exception oop.
__ ld(R3_ARG1, in_bytes(JavaThread::exception_oop_offset()), R16_thread);
// Get the exception pc in case we are deoptimized.
__ ld(R4_ARG2, in_bytes(JavaThread::exception_pc_offset()), R16_thread);
// Reset thread values.
__ li(R0, 0); #ifdef ASSERT
__ std(R0, in_bytes(JavaThread::exception_handler_pc_offset()), R16_thread);
__ std(R0, in_bytes(JavaThread::exception_pc_offset()), R16_thread); #endif // Clear the exception oop so GC no longer processes it as a root.
__ std(R0, in_bytes(JavaThread::exception_oop_offset()), R16_thread);
// Move exception pc into SR_LR.
__ mtlr(R4_ARG2);
__ bctr();
// Make sure all code is generated.
masm->flush();
// Set exception blob.
_exception_blob = ExceptionBlob::create(&buffer, oop_maps,
frame_size_in_bytes/wordSize);
}
#endif// COMPILER2
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