1 /*
2 * Copyright (c) 1997, 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 #include "asm/macroAssembler.hpp"
27 #include "code/vtableStubs.hpp"
28 #include "interp_masm_x86.hpp"
29 #include "memory/resourceArea.hpp"
30 #include "oops/compiledICHolder.hpp"
31 #include "oops/instanceKlass.hpp"
32 #include "oops/klassVtable.hpp"
33 #include "runtime/sharedRuntime.hpp"
34 #include "vmreg_x86.inline.hpp"
35 #ifdef COMPILER2
36 #include "opto/runtime.hpp"
37 #endif
38
39 // machine-dependent part of VtableStubs: create VtableStub of correct size and
40 // initialize its code
41
42 #define __ masm->
43
44 #ifndef PRODUCT
45 extern "C" void bad_compiled_vtable_index(JavaThread* thread, oop receiver, int index);
46 #endif
47
48 // These stubs are used by the compiler only.
49 // Argument registers, which must be preserved:
50 // rcx - receiver (always first argument)
51 // rdx - second argument (if any)
52 // Other registers that might be usable:
53 // rax - inline cache register (is interface for itable stub)
54 // rbx - method (used when calling out to interpreter)
55 // Available now, but may become callee-save at some point:
56 // rsi, rdi
57 // Note that rax and rdx are also used for return values.
58 //
59 VtableStub* VtableStubs::create_vtable_stub(int vtable_index) {
60 const int i486_code_length = VtableStub::pd_code_size_limit(true);
61 VtableStub* s = new(i486_code_length) VtableStub(true, vtable_index);
62 // Can be NULL if there is no free space in the code cache.
63 if (s == NULL) {
64 return NULL;
65 }
66
67 ResourceMark rm;
68 CodeBuffer cb(s->entry_point(), i486_code_length);
69 MacroAssembler* masm = new MacroAssembler(&cb);
70
71 #ifndef PRODUCT
72
73 if (CountCompiledCalls) {
74 __ incrementl(ExternalAddress((address) SharedRuntime::nof_megamorphic_calls_addr()));
75 }
76 #endif /* PRODUCT */
77
78 // get receiver (need to skip return address on top of stack)
79 assert(VtableStub::receiver_location() == rcx->as_VMReg(), "receiver expected in rcx");
80
81 // get receiver klass
82 address npe_addr = __ pc();
83 __ movptr(rax, Address(rcx, oopDesc::klass_offset_in_bytes()));
84
85 #ifndef PRODUCT
86 if (DebugVtables) {
87 Label L;
88 // check offset vs vtable length
89 __ cmpl(Address(rax, Klass::vtable_length_offset()), vtable_index*vtableEntry::size());
90 __ jcc(Assembler::greater, L);
91 __ movl(rbx, vtable_index);
92 __ call_VM(noreg, CAST_FROM_FN_PTR(address, bad_compiled_vtable_index), rcx, rbx);
93 __ bind(L);
94 }
95 #endif // PRODUCT
96
97 const Register method = rbx;
98
99 // load Method* and target address
100 __ lookup_virtual_method(rax, vtable_index, method);
101
102 if (DebugVtables) {
103 Label L;
104 __ cmpptr(method, (int32_t)NULL_WORD);
105 __ jcc(Assembler::equal, L);
106 __ cmpptr(Address(method, Method::from_compiled_offset()), (int32_t)NULL_WORD);
107 __ jcc(Assembler::notZero, L);
108 __ stop("Vtable entry is NULL");
109 __ bind(L);
110 }
111
112 // rax,: receiver klass
113 // method (rbx): Method*
114 // rcx: receiver
115 address ame_addr = __ pc();
116 __ jmp( Address(method, Method::from_compiled_offset()));
117
118 masm->flush();
119
120 if (PrintMiscellaneous && (WizardMode || Verbose)) {
121 tty->print_cr("vtable #%d at " PTR_FORMAT "[%d] left over: %d",
122 vtable_index, p2i(s->entry_point()),
123 (int)(s->code_end() - s->entry_point()),
124 (int)(s->code_end() - __ pc()));
125 }
126 guarantee(__ pc() <= s->code_end(), "overflowed buffer");
127 // shut the door on sizing bugs
128 int slop = 3; // 32-bit offset is this much larger than an 8-bit one
129 assert(vtable_index > 10 || __ pc() + slop <= s->code_end(), "room for 32-bit offset");
130
131 s->set_exception_points(npe_addr, ame_addr);
132 return s;
133 }
134
135
136 VtableStub* VtableStubs::create_itable_stub(int itable_index) {
137 // Note well: pd_code_size_limit is the absolute minimum we can get away with. If you
138 // add code here, bump the code stub size returned by pd_code_size_limit!
139 const int i486_code_length = VtableStub::pd_code_size_limit(false);
140 VtableStub* s = new(i486_code_length) VtableStub(false, itable_index);
141 // Can be NULL if there is no free space in the code cache.
142 if (s == NULL) {
143 return NULL;
144 }
145
146 ResourceMark rm;
147 CodeBuffer cb(s->entry_point(), i486_code_length);
148 MacroAssembler* masm = new MacroAssembler(&cb);
149
150 // Entry arguments:
151 // rax: CompiledICHolder
152 // rcx: Receiver
153
154 #ifndef PRODUCT
155 if (CountCompiledCalls) {
156 __ incrementl(ExternalAddress((address) SharedRuntime::nof_megamorphic_calls_addr()));
157 }
158 #endif /* PRODUCT */
159
160 // Most registers are in use; we'll use rax, rbx, rsi, rdi
161 // (If we need to make rsi, rdi callee-save, do a push/pop here.)
162 const Register recv_klass_reg = rsi;
163 const Register holder_klass_reg = rax; // declaring interface klass (DECC)
164 const Register resolved_klass_reg = rbx; // resolved interface klass (REFC)
165 const Register temp_reg = rdi;
166
167 const Register icholder_reg = rax;
168 __ movptr(resolved_klass_reg, Address(icholder_reg, CompiledICHolder::holder_klass_offset()));
169 __ movptr(holder_klass_reg, Address(icholder_reg, CompiledICHolder::holder_metadata_offset()));
170
171 Label L_no_such_interface;
172
173 // get receiver klass (also an implicit null-check)
174 address npe_addr = __ pc();
175 assert(VtableStub::receiver_location() == rcx->as_VMReg(), "receiver expected in rcx");
176 __ load_klass(recv_klass_reg, rcx);
177
178 // Receiver subtype check against REFC.
179 // Destroys recv_klass_reg value.
180 __ lookup_interface_method(// inputs: rec. class, interface
181 recv_klass_reg, resolved_klass_reg, noreg,
182 // outputs: scan temp. reg1, scan temp. reg2
183 recv_klass_reg, temp_reg,
184 L_no_such_interface,
185 /*return_method=*/false);
186
187 // Get selected method from declaring class and itable index
188 const Register method = rbx;
189 __ load_klass(recv_klass_reg, rcx); // restore recv_klass_reg
190 __ lookup_interface_method(// inputs: rec. class, interface, itable index
191 recv_klass_reg, holder_klass_reg, itable_index,
192 // outputs: method, scan temp. reg
193 method, temp_reg,
194 L_no_such_interface);
195
196 // method (rbx): Method*
197 // rcx: receiver
198
199 #ifdef ASSERT
200 if (DebugVtables) {
201 Label L1;
202 __ cmpptr(method, (int32_t)NULL_WORD);
203 __ jcc(Assembler::equal, L1);
204 __ cmpptr(Address(method, Method::from_compiled_offset()), (int32_t)NULL_WORD);
205 __ jcc(Assembler::notZero, L1);
206 __ stop("Method* is null");
207 __ bind(L1);
208 }
209 #endif // ASSERT
210
211 address ame_addr = __ pc();
212 __ jmp(Address(method, Method::from_compiled_offset()));
213
214 __ bind(L_no_such_interface);
215 __ jump(RuntimeAddress(StubRoutines::throw_IncompatibleClassChangeError_entry()));
216
217 __ flush();
218
219 if (PrintMiscellaneous && (WizardMode || Verbose)) {
220 tty->print_cr("itable #%d at " PTR_FORMAT "[%d] left over: %d",
221 itable_index, p2i(s->entry_point()),
222 (int)(s->code_end() - s->entry_point()),
223 (int)(s->code_end() - __ pc()));
224 }
225 guarantee(__ pc() <= s->code_end(), "overflowed buffer");
226 // shut the door on sizing bugs
227 int slop = 3; // 32-bit offset is this much larger than an 8-bit one
228 assert(itable_index > 10 || __ pc() + slop <= s->code_end(), "room for 32-bit offset");
229
230 s->set_exception_points(npe_addr, ame_addr);
231 return s;
232 }
233
234
235
236 int VtableStub::pd_code_size_limit(bool is_vtable_stub) {
237 if (is_vtable_stub) {
238 // Vtable stub size
239 return (DebugVtables ? 210 : 16) + (CountCompiledCalls ? 6 : 0);
240 } else {
241 // Itable stub size
242 return (DebugVtables ? 256 : 110) + (CountCompiledCalls ? 6 : 0);
243 }
244 // In order to tune these parameters, run the JVM with VM options
245 // +PrintMiscellaneous and +WizardMode to see information about
246 // actual itable stubs. Look for lines like this:
247 // itable #1 at 0x5551212[65] left over: 3
248 // Reduce the constants so that the "left over" number is >=3
249 // for the common cases.
250 // Do not aim at a left-over number of zero, because a
251 // large vtable or itable index (> 16) will require a 32-bit
252 // immediate displacement instead of an 8-bit one.
253 //
254 // The JVM98 app. _202_jess has a megamorphic interface call.
255 // The itable code looks like this:
256 // Decoding VtableStub itbl[1]@1
257 // mov 0x4(%ecx),%esi
258 // mov 0xe8(%esi),%edi
259 // lea 0x130(%esi,%edi,4),%edi
260 // add $0x7,%edi
261 // and $0xfffffff8,%edi
262 // lea 0x4(%esi),%esi
263 // mov (%edi),%ebx
264 // cmp %ebx,%eax
265 // je success
266 // loop:
267 // test %ebx,%ebx
268 // je throw_icce
269 // add $0x8,%edi
270 // mov (%edi),%ebx
271 // cmp %ebx,%eax
272 // jne loop
273 // success:
274 // mov 0x4(%edi),%edi
275 // mov (%esi,%edi,1),%ebx
276 // jmp *0x44(%ebx)
277 // throw_icce:
278 // jmp throw_ICCE_entry
279 }
280
281 int VtableStub::pd_code_alignment() {
282 return wordSize;
283 }