1 /*
2 * Copyright (c) 1998, 2010, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25
26 #include "incls/_precompiled.incl"
27 #include "incls/_runtime_x86_32.cpp.incl"
28
29 #define __ masm->
30
31 ExceptionBlob* OptoRuntime::_exception_blob;
32
33 //------------------------------generate_exception_blob---------------------------
34 // creates exception blob at the end
35 // Using exception blob, this code is jumped from a compiled method.
36 //
37 // Given an exception pc at a call we call into the runtime for the
38 // handler in this method. This handler might merely restore state
39 // (i.e. callee save registers) unwind the frame and jump to the
40 // exception handler for the nmethod if there is no Java level handler
41 // for the nmethod.
42 //
43 // This code is entered with a jmp.
44 //
45 // Arguments:
46 // rax: exception oop
47 // rdx: exception pc
48 //
49 // Results:
50 // rax: exception oop
51 // rdx: exception pc in caller or ???
52 // destination: exception handler of caller
53 //
54 // Note: the exception pc MUST be at a call (precise debug information)
55 // Only register rax, rdx, rcx are not callee saved.
56 //
57
58 void OptoRuntime::generate_exception_blob() {
59
60 // Capture info about frame layout
61 enum layout {
62 thread_off, // last_java_sp
63 // The frame sender code expects that rbp will be in the "natural" place and
64 // will override any oopMap setting for it. We must therefore force the layout
65 // so that it agrees with the frame sender code.
66 rbp_off,
67 return_off, // slot for return address
68 framesize
69 };
70
71 // allocate space for the code
72 ResourceMark rm;
73 // setup code generation tools
74 CodeBuffer buffer("exception_blob", 512, 512);
75 MacroAssembler* masm = new MacroAssembler(&buffer);
76
77 OopMapSet *oop_maps = new OopMapSet();
78
79 address start = __ pc();
80
81 __ push(rdx);
82 __ subptr(rsp, return_off * wordSize); // Prolog!
83
84 // rbp, location is implicitly known
85 __ movptr(Address(rsp,rbp_off *wordSize), rbp);
86
87 // Store exception in Thread object. We cannot pass any arguments to the
88 // handle_exception call, since we do not want to make any assumption
89 // about the size of the frame where the exception happened in.
90 __ get_thread(rcx);
91 __ movptr(Address(rcx, JavaThread::exception_oop_offset()), rax);
92 __ movptr(Address(rcx, JavaThread::exception_pc_offset()), rdx);
93
94 // This call does all the hard work. It checks if an exception handler
95 // exists in the method.
96 // If so, it returns the handler address.
97 // If not, it prepares for stack-unwinding, restoring the callee-save
98 // registers of the frame being removed.
99 //
100 __ movptr(Address(rsp, thread_off * wordSize), rcx); // Thread is first argument
101 __ set_last_Java_frame(rcx, noreg, noreg, NULL);
102
103 __ call(RuntimeAddress(CAST_FROM_FN_PTR(address, OptoRuntime::handle_exception_C)));
104
105 // No registers to map, rbp is known implicitly
106 oop_maps->add_gc_map( __ pc() - start, new OopMap( framesize, 0 ));
107 __ get_thread(rcx);
108 __ reset_last_Java_frame(rcx, false, false);
109
110 // Restore callee-saved registers
111 __ movptr(rbp, Address(rsp, rbp_off * wordSize));
112
113 __ addptr(rsp, return_off * wordSize); // Epilog!
114 __ pop(rdx); // Exception pc
115
116 // rax: exception handler for given <exception oop/exception pc>
117
118 // Restore SP from BP if the exception PC is a MethodHandle call site.
119 __ cmpl(Address(rcx, JavaThread::is_method_handle_return_offset()), 0);
120 __ cmovptr(Assembler::notEqual, rsp, rbp_mh_SP_save);
121
122 // We have a handler in rax, (could be deopt blob)
123 // rdx - throwing pc, deopt blob will need it.
124
125 __ push(rax);
126
127 // Get the exception
128 __ movptr(rax, Address(rcx, JavaThread::exception_oop_offset()));
129 // Get the exception pc in case we are deoptimized
130 __ movptr(rdx, Address(rcx, JavaThread::exception_pc_offset()));
131 #ifdef ASSERT
132 __ movptr(Address(rcx, JavaThread::exception_handler_pc_offset()), NULL_WORD);
133 __ movptr(Address(rcx, JavaThread::exception_pc_offset()), NULL_WORD);
134 #endif
135 // Clear the exception oop so GC no longer processes it as a root.
136 __ movptr(Address(rcx, JavaThread::exception_oop_offset()), NULL_WORD);
137
138 __ pop(rcx);
139
140 // rax: exception oop
141 // rcx: exception handler
142 // rdx: exception pc
143 __ jmp (rcx);
144
145 // -------------
146 // make sure all code is generated
147 masm->flush();
148
149 _exception_blob = ExceptionBlob::create(&buffer, oop_maps, framesize);
150 }