1 /*
2 * Copyright (c) 1998, 2016, 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 #include "precompiled.hpp"
26 #ifdef COMPILER2
27 #include "asm/macroAssembler.hpp"
28 #include "asm/macroAssembler.inline.hpp"
29 #include "classfile/systemDictionary.hpp"
30 #include "code/vmreg.hpp"
31 #include "interpreter/interpreter.hpp"
32 #include "memory/resourceArea.hpp"
33 #include "opto/runtime.hpp"
34 #include "runtime/sharedRuntime.hpp"
35 #include "runtime/stubRoutines.hpp"
36 #include "runtime/vframeArray.hpp"
37 #include "utilities/globalDefinitions.hpp"
38 #include "vmreg_x86.inline.hpp"
39 #endif
40
41
42 #define __ masm->
43
44 //------------------------------generate_exception_blob---------------------------
45 // creates exception blob at the end
46 // Using exception blob, this code is jumped from a compiled method.
47 //
48 // Given an exception pc at a call we call into the runtime for the
49 // handler in this method. This handler might merely restore state
50 // (i.e. callee save registers) unwind the frame and jump to the
51 // exception handler for the nmethod if there is no Java level handler
52 // for the nmethod.
53 //
54 // This code is entered with a jmp.
55 //
56 // Arguments:
57 // rax: exception oop
58 // rdx: exception pc
59 //
60 // Results:
61 // rax: exception oop
62 // rdx: exception pc in caller or ???
63 // destination: exception handler of caller
64 //
65 // Note: the exception pc MUST be at a call (precise debug information)
66 // Only register rax, rdx, rcx are not callee saved.
67 //
68
generate_exception_blob()69 void OptoRuntime::generate_exception_blob() {
70
71 // Capture info about frame layout
72 enum layout {
73 thread_off, // last_java_sp
74 // The frame sender code expects that rbp will be in the "natural" place and
75 // will override any oopMap setting for it. We must therefore force the layout
76 // so that it agrees with the frame sender code.
77 rbp_off,
78 return_off, // slot for return address
79 framesize
80 };
81
82 // allocate space for the code
83 ResourceMark rm;
84 // setup code generation tools
85 CodeBuffer buffer("exception_blob", 512, 512);
86 MacroAssembler* masm = new MacroAssembler(&buffer);
87
88 OopMapSet *oop_maps = new OopMapSet();
89
90 address start = __ pc();
91
92 __ push(rdx);
93 __ subptr(rsp, return_off * wordSize); // Prolog!
94
95 // rbp, location is implicitly known
96 __ movptr(Address(rsp,rbp_off *wordSize), rbp);
97
98 // Store exception in Thread object. We cannot pass any arguments to the
99 // handle_exception call, since we do not want to make any assumption
100 // about the size of the frame where the exception happened in.
101 __ get_thread(rcx);
102 __ movptr(Address(rcx, JavaThread::exception_oop_offset()), rax);
103 __ movptr(Address(rcx, JavaThread::exception_pc_offset()), rdx);
104
105 // This call does all the hard work. It checks if an exception handler
106 // exists in the method.
107 // If so, it returns the handler address.
108 // If not, it prepares for stack-unwinding, restoring the callee-save
109 // registers of the frame being removed.
110 //
111 __ movptr(Address(rsp, thread_off * wordSize), rcx); // Thread is first argument
112 __ set_last_Java_frame(rcx, noreg, noreg, NULL);
113
114 __ call(RuntimeAddress(CAST_FROM_FN_PTR(address, OptoRuntime::handle_exception_C)));
115
116 // No registers to map, rbp is known implicitly
117 oop_maps->add_gc_map( __ pc() - start, new OopMap( framesize, 0 ));
118 __ get_thread(rcx);
119 __ reset_last_Java_frame(rcx, false);
120
121 // Restore callee-saved registers
122 __ movptr(rbp, Address(rsp, rbp_off * wordSize));
123
124 __ addptr(rsp, return_off * wordSize); // Epilog!
125 __ pop(rdx); // Exception pc
126
127 // rax: exception handler for given <exception oop/exception pc>
128
129 // We have a handler in rax, (could be deopt blob)
130 // rdx - throwing pc, deopt blob will need it.
131
132 __ push(rax);
133
134 // Get the exception
135 __ movptr(rax, Address(rcx, JavaThread::exception_oop_offset()));
136 // Get the exception pc in case we are deoptimized
137 __ movptr(rdx, Address(rcx, JavaThread::exception_pc_offset()));
138 #ifdef ASSERT
139 __ movptr(Address(rcx, JavaThread::exception_handler_pc_offset()), NULL_WORD);
140 __ movptr(Address(rcx, JavaThread::exception_pc_offset()), NULL_WORD);
141 #endif
142 // Clear the exception oop so GC no longer processes it as a root.
143 __ movptr(Address(rcx, JavaThread::exception_oop_offset()), NULL_WORD);
144
145 __ pop(rcx);
146
147 // rax: exception oop
148 // rcx: exception handler
149 // rdx: exception pc
150 __ jmp (rcx);
151
152 // -------------
153 // make sure all code is generated
154 masm->flush();
155
156 _exception_blob = ExceptionBlob::create(&buffer, oop_maps, framesize);
157 }
158