1 /*
2 * Copyright (c) 1997, 2009, 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 "incls/_precompiled.incl"
26 #include "incls/_vtableStubs_x86_32.cpp.incl"
27
28 // machine-dependent part of VtableStubs: create VtableStub of correct size and
29 // initialize its code
30
31 #define __ masm->
32
33 #ifndef PRODUCT
34 extern "C" void bad_compiled_vtable_index(JavaThread* thread, oop receiver, int index);
35 #endif
36
37 // These stubs are used by the compiler only.
38 // Argument registers, which must be preserved:
39 // rcx - receiver (always first argument)
40 // rdx - second argument (if any)
41 // Other registers that might be usable:
42 // rax - inline cache register (is interface for itable stub)
43 // rbx - method (used when calling out to interpreter)
44 // Available now, but may become callee-save at some point:
45 // rsi, rdi
46 // Note that rax and rdx are also used for return values.
47 //
48 VtableStub* VtableStubs::create_vtable_stub(int vtable_index) {
49 const int i486_code_length = VtableStub::pd_code_size_limit(true);
50 VtableStub* s = new(i486_code_length) VtableStub(true, vtable_index);
51 ResourceMark rm;
52 CodeBuffer cb(s->entry_point(), i486_code_length);
53 MacroAssembler* masm = new MacroAssembler(&cb);
54
55 #ifndef PRODUCT
56
57 if (CountCompiledCalls) {
58 __ incrementl(ExternalAddress((address) SharedRuntime::nof_megamorphic_calls_addr()));
59 }
60 #endif /* PRODUCT */
61
62 // get receiver (need to skip return address on top of stack)
63 assert(VtableStub::receiver_location() == rcx->as_VMReg(), "receiver expected in rcx");
64
65 // get receiver klass
66 address npe_addr = __ pc();
67 __ movptr(rax, Address(rcx, oopDesc::klass_offset_in_bytes()));
68 // compute entry offset (in words)
69 int entry_offset = instanceKlass::vtable_start_offset() + vtable_index*vtableEntry::size();
70 #ifndef PRODUCT
71 if (DebugVtables) {
72 Label L;
73 // check offset vs vtable length
74 __ cmpl(Address(rax, instanceKlass::vtable_length_offset()*wordSize), vtable_index*vtableEntry::size());
75 __ jcc(Assembler::greater, L);
76 __ movl(rbx, vtable_index);
77 __ call_VM(noreg, CAST_FROM_FN_PTR(address, bad_compiled_vtable_index), rcx, rbx);
78 __ bind(L);
79 }
80 #endif // PRODUCT
81
82 const Register method = rbx;
83
84 // load methodOop and target address
85 __ movptr(method, Address(rax, entry_offset*wordSize + vtableEntry::method_offset_in_bytes()));
86 if (DebugVtables) {
87 Label L;
88 __ cmpptr(method, (int32_t)NULL_WORD);
89 __ jcc(Assembler::equal, L);
90 __ cmpptr(Address(method, methodOopDesc::from_compiled_offset()), (int32_t)NULL_WORD);
91 __ jcc(Assembler::notZero, L);
92 __ stop("Vtable entry is NULL");
93 __ bind(L);
94 }
95
96 // rax,: receiver klass
97 // method (rbx): methodOop
98 // rcx: receiver
99 address ame_addr = __ pc();
100 __ jmp( Address(method, methodOopDesc::from_compiled_offset()));
101
102 masm->flush();
103
104 if (PrintMiscellaneous && (WizardMode || Verbose)) {
105 tty->print_cr("vtable #%d at "PTR_FORMAT"[%d] left over: %d",
106 vtable_index, s->entry_point(),
107 (int)(s->code_end() - s->entry_point()),
108 (int)(s->code_end() - __ pc()));
109 }
110 guarantee(__ pc() <= s->code_end(), "overflowed buffer");
111 // shut the door on sizing bugs
112 int slop = 3; // 32-bit offset is this much larger than an 8-bit one
113 assert(vtable_index > 10 || __ pc() + slop <= s->code_end(), "room for 32-bit offset");
114
115 s->set_exception_points(npe_addr, ame_addr);
116 return s;
117 }
118
119
120 VtableStub* VtableStubs::create_itable_stub(int itable_index) {
121 // Note well: pd_code_size_limit is the absolute minimum we can get away with. If you
122 // add code here, bump the code stub size returned by pd_code_size_limit!
123 const int i486_code_length = VtableStub::pd_code_size_limit(false);
124 VtableStub* s = new(i486_code_length) VtableStub(false, itable_index);
125 ResourceMark rm;
126 CodeBuffer cb(s->entry_point(), i486_code_length);
127 MacroAssembler* masm = new MacroAssembler(&cb);
128
129 // Entry arguments:
130 // rax,: Interface
131 // rcx: Receiver
132
133 #ifndef PRODUCT
134 if (CountCompiledCalls) {
135 __ incrementl(ExternalAddress((address) SharedRuntime::nof_megamorphic_calls_addr()));
136 }
137 #endif /* PRODUCT */
138 // get receiver (need to skip return address on top of stack)
139
140 assert(VtableStub::receiver_location() == rcx->as_VMReg(), "receiver expected in rcx");
141
142 // get receiver klass (also an implicit null-check)
143 address npe_addr = __ pc();
144 __ movptr(rsi, Address(rcx, oopDesc::klass_offset_in_bytes()));
145
146 // Most registers are in use; we'll use rax, rbx, rsi, rdi
147 // (If we need to make rsi, rdi callee-save, do a push/pop here.)
148 const Register method = rbx;
149 Label throw_icce;
150
151 // Get methodOop and entrypoint for compiler
152 __ lookup_interface_method(// inputs: rec. class, interface, itable index
153 rsi, rax, itable_index,
154 // outputs: method, scan temp. reg
155 method, rdi,
156 throw_icce);
157
158 // method (rbx): methodOop
159 // rcx: receiver
160
161 #ifdef ASSERT
162 if (DebugVtables) {
163 Label L1;
164 __ cmpptr(method, (int32_t)NULL_WORD);
165 __ jcc(Assembler::equal, L1);
166 __ cmpptr(Address(method, methodOopDesc::from_compiled_offset()), (int32_t)NULL_WORD);
167 __ jcc(Assembler::notZero, L1);
168 __ stop("methodOop is null");
169 __ bind(L1);
170 }
171 #endif // ASSERT
172
173 address ame_addr = __ pc();
174 __ jmp(Address(method, methodOopDesc::from_compiled_offset()));
175
176 __ bind(throw_icce);
177 __ jump(RuntimeAddress(StubRoutines::throw_IncompatibleClassChangeError_entry()));
178 masm->flush();
179
180 if (PrintMiscellaneous && (WizardMode || Verbose)) {
181 tty->print_cr("itable #%d at "PTR_FORMAT"[%d] left over: %d",
182 itable_index, s->entry_point(),
183 (int)(s->code_end() - s->entry_point()),
184 (int)(s->code_end() - __ pc()));
185 }
186 guarantee(__ pc() <= s->code_end(), "overflowed buffer");
187 // shut the door on sizing bugs
188 int slop = 3; // 32-bit offset is this much larger than an 8-bit one
189 assert(itable_index > 10 || __ pc() + slop <= s->code_end(), "room for 32-bit offset");
190
191 s->set_exception_points(npe_addr, ame_addr);
192 return s;
193 }
194
195
196
197 int VtableStub::pd_code_size_limit(bool is_vtable_stub) {
198 if (is_vtable_stub) {
199 // Vtable stub size
200 return (DebugVtables ? 210 : 16) + (CountCompiledCalls ? 6 : 0);
201 } else {
202 // Itable stub size
203 return (DebugVtables ? 256 : 66) + (CountCompiledCalls ? 6 : 0);
204 }
205 // In order to tune these parameters, run the JVM with VM options
206 // +PrintMiscellaneous and +WizardMode to see information about
207 // actual itable stubs. Look for lines like this:
208 // itable #1 at 0x5551212[65] left over: 3
209 // Reduce the constants so that the "left over" number is >=3
210 // for the common cases.
211 // Do not aim at a left-over number of zero, because a
212 // large vtable or itable index (> 16) will require a 32-bit
213 // immediate displacement instead of an 8-bit one.
214 //
215 // The JVM98 app. _202_jess has a megamorphic interface call.
216 // The itable code looks like this:
217 // Decoding VtableStub itbl[1]@1
218 // mov 0x4(%ecx),%esi
219 // mov 0xe8(%esi),%edi
220 // lea 0x130(%esi,%edi,4),%edi
221 // add $0x7,%edi
222 // and $0xfffffff8,%edi
223 // lea 0x4(%esi),%esi
224 // mov (%edi),%ebx
225 // cmp %ebx,%eax
226 // je success
227 // loop:
228 // test %ebx,%ebx
229 // je throw_icce
230 // add $0x8,%edi
231 // mov (%edi),%ebx
232 // cmp %ebx,%eax
233 // jne loop
234 // success:
235 // mov 0x4(%edi),%edi
236 // mov (%esi,%edi,1),%ebx
237 // jmp *0x44(%ebx)
238 // throw_icce:
239 // jmp throw_ICCE_entry
240 }
241
242 int VtableStub::pd_code_alignment() {
243 return wordSize;
244 }