1 #ifdef USE_PRAGMA_IDENT_SRC
2 #pragma ident "@(#)runtime_x86_32.cpp 1.113 07/09/17 09:26:02 JVM"
3 #endif
4 /*
5 * Copyright 1998-2006 Sun Microsystems, Inc. All Rights Reserved.
6 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
7 *
8 * This code is free software; you can redistribute it and/or modify it
9 * under the terms of the GNU General Public License version 2 only, as
10 * published by the Free Software Foundation.
11 *
12 * This code is distributed in the hope that it will be useful, but WITHOUT
13 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
14 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
15 * version 2 for more details (a copy is included in the LICENSE file that
16 * accompanied this code).
17 *
18 * You should have received a copy of the GNU General Public License version
19 * 2 along with this work; if not, write to the Free Software Foundation,
20 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
21 *
22 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
23 * CA 95054 USA or visit www.sun.com if you need additional information or
24 * have any questions.
25 *
26 */
27
28
29 #include "incls/_precompiled.incl"
30 #include "incls/_runtime_x86_32.cpp.incl"
31
32 #define __ masm->
33
34 ExceptionBlob* OptoRuntime::_exception_blob;
35
36 //------------------------------generate_exception_blob---------------------------
37 // creates exception blob at the end
38 // Using exception blob, this code is jumped from a compiled method.
39 //
40 // Given an exception pc at a call we call into the runtime for the
41 // handler in this method. This handler might merely restore state
42 // (i.e. callee save registers) unwind the frame and jump to the
43 // exception handler for the nmethod if there is no Java level handler
44 // for the nmethod.
45 //
46 // This code is entered with a jmp.
47 //
48 // Arguments:
49 // rax,: exception oop
50 // rdx: exception pc
51 //
52 // Results:
53 // rax,: exception oop
54 // rdx: exception pc in caller or ???
55 // destination: exception handler of caller
56 //
57 // Note: the exception pc MUST be at a call (precise debug information)
58 // Only register rax, rdx, rcx are not callee saved.
59 //
60
61 void OptoRuntime::generate_exception_blob() {
62
63 // Capture info about frame layout
64 enum layout {
65 thread_off, // last_java_sp
66 // The frame sender code expects that rbp will be in the "natural" place and
67 // will override any oopMap setting for it. We must therefore force the layout
68 // so that it agrees with the frame sender code.
69 rbp_off,
70 return_off, // slot for return address
71 framesize
72 };
73
74 // allocate space for the code
75 ResourceMark rm;
76 // setup code generation tools
77 CodeBuffer buffer("exception_blob", 512, 512);
78 MacroAssembler* masm = new MacroAssembler(&buffer);
79
80 OopMapSet *oop_maps = new OopMapSet();
81
82 address start = __ pc();
83
84 __ pushl(rdx);
85 __ subl(rsp, return_off * wordSize); // Prolog!
86
87 // rbp, location is implicitly known
88 __ movl(Address(rsp,rbp_off *wordSize),rbp);
89
90 // Store exception in Thread object. We cannot pass any arguments to the
91 // handle_exception call, since we do not want to make any assumption
92 // about the size of the frame where the exception happened in.
93 __ get_thread(rcx);
94 __ movl(Address(rcx, JavaThread::exception_oop_offset()), rax);
95 __ movl(Address(rcx, JavaThread::exception_pc_offset()), rdx);
96
97 // This call does all the hard work. It checks if an exception handler
98 // exists in the method.
99 // If so, it returns the handler address.
100 // If not, it prepares for stack-unwinding, restoring the callee-save
101 // registers of the frame being removed.
102 //
103 __ movl(Address(rsp, thread_off * wordSize), rcx); // Thread is first argument
104 __ set_last_Java_frame(rcx, noreg, noreg, NULL);
105
106 __ call(RuntimeAddress(CAST_FROM_FN_PTR(address, OptoRuntime::handle_exception_C)));
107
108 // No registers to map, rbp is known implicitly
109 oop_maps->add_gc_map( __ pc() - start, new OopMap( framesize, 0 ));
110 __ get_thread(rcx);
111 __ reset_last_Java_frame(rcx, false, false);
112
113 // Restore callee-saved registers
114 __ movl(rbp, Address(rsp, rbp_off * wordSize));
115
116 __ addl(rsp, return_off * wordSize); // Epilog!
117 __ popl(rdx); // Exception pc
118
119
120 // rax,: exception handler for given <exception oop/exception pc>
121
122 // We have a handler in rax, (could be deopt blob)
123 // rdx - throwing pc, deopt blob will need it.
124
125 __ pushl(rax);
126
127 // rcx contains handler address
128
129 __ get_thread(rcx); // TLS
130 // Get the exception
131 __ movl(rax, Address(rcx, JavaThread::exception_oop_offset()));
132 // Get the exception pc in case we are deoptimized
133 __ movl(rdx, Address(rcx, JavaThread::exception_pc_offset()));
134 #ifdef ASSERT
135 __ movl(Address(rcx, JavaThread::exception_handler_pc_offset()), 0);
136 __ movl(Address(rcx, JavaThread::exception_pc_offset()), 0);
137 #endif
138 // Clear the exception oop so GC no longer processes it as a root.
139 __ movl(Address(rcx, JavaThread::exception_oop_offset()), 0);
140
141 __ popl(rcx);
142
143 // rax,: exception oop
144 // rcx: exception handler
145 // rdx: exception pc
146 __ jmp (rcx);
147
148 // -------------
149 // make sure all code is generated
150 masm->flush();
151
152 _exception_blob = ExceptionBlob::create(&buffer, oop_maps, framesize);
153 }