1 /*
2 * Copyright (c) 2003, 2017, 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 PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC
40
41 // machine-dependent part of VtableStubs: create VtableStub of correct size and
42 // initialize its code
43
44 #define __ masm->
45
46 #ifndef PRODUCT
47 extern "C" void bad_compiled_vtable_index(JavaThread* thread,
48 oop receiver,
49 int index);
50 #endif
51
52 VtableStub* VtableStubs::create_vtable_stub(int vtable_index) {
53 const int amd64_code_length = VtableStub::pd_code_size_limit(true);
54 VtableStub* s = new(amd64_code_length) VtableStub(true, vtable_index);
55 // Can be NULL if there is no free space in the code cache.
56 if (s == NULL) {
57 return NULL;
58 }
59
60 ResourceMark rm;
61 CodeBuffer cb(s->entry_point(), amd64_code_length);
62 MacroAssembler* masm = new MacroAssembler(&cb);
63
64 #ifndef PRODUCT
65 if (CountCompiledCalls) {
66 __ incrementl(ExternalAddress((address) SharedRuntime::nof_megamorphic_calls_addr()));
67 }
68 #endif
69
70 // get receiver (need to skip return address on top of stack)
71 assert(VtableStub::receiver_location() == j_rarg0->as_VMReg(), "receiver expected in j_rarg0");
72
73 // Free registers (non-args) are rax, rbx
74
75 // get receiver klass
76 address npe_addr = __ pc();
77 __ load_klass(rax, j_rarg0);
78
79 #ifndef PRODUCT
80 if (DebugVtables) {
81 Label L;
82 // check offset vs vtable length
83 __ cmpl(Address(rax, InstanceKlass::vtable_length_offset() * wordSize),
84 vtable_index * vtableEntry::size());
85 __ jcc(Assembler::greater, L);
86 __ movl(rbx, vtable_index);
87 __ call_VM(noreg,
88 CAST_FROM_FN_PTR(address, bad_compiled_vtable_index), j_rarg0, rbx);
89 __ bind(L);
90 }
91 #endif // PRODUCT
92
93 // load Method* and target address
94 const Register method = rbx;
95
96 __ lookup_virtual_method(rax, vtable_index, method);
97
98 if (DebugVtables) {
99 Label L;
100 __ cmpptr(method, (int32_t)NULL_WORD);
101 __ jcc(Assembler::equal, L);
102 __ cmpptr(Address(method, Method::from_compiled_offset()), (int32_t)NULL_WORD);
103 __ jcc(Assembler::notZero, L);
104 __ stop("Vtable entry is NULL");
105 __ bind(L);
106 }
107 // rax: receiver klass
108 // rbx: Method*
109 // rcx: receiver
110 address ame_addr = __ pc();
111 __ jmp( Address(rbx, Method::from_compiled_offset()));
112
113 __ flush();
114
115 if (PrintMiscellaneous && (WizardMode || Verbose)) {
116 tty->print_cr("vtable #%d at "PTR_FORMAT"[%d] left over: %d",
117 vtable_index, s->entry_point(),
118 (int)(s->code_end() - s->entry_point()),
119 (int)(s->code_end() - __ pc()));
120 }
121 guarantee(__ pc() <= s->code_end(), "overflowed buffer");
122 // shut the door on sizing bugs
123 int slop = 3; // 32-bit offset is this much larger than an 8-bit one
124 assert(vtable_index > 10 || __ pc() + slop <= s->code_end(), "room for 32-bit offset");
125
126 s->set_exception_points(npe_addr, ame_addr);
127 return s;
128 }
129
130
131 VtableStub* VtableStubs::create_itable_stub(int itable_index) {
132 // Note well: pd_code_size_limit is the absolute minimum we can get
133 // away with. If you add code here, bump the code stub size
134 // returned by pd_code_size_limit!
135 const int amd64_code_length = VtableStub::pd_code_size_limit(false);
136 VtableStub* s = new(amd64_code_length) VtableStub(false, itable_index);
137 // Can be NULL if there is no free space in the code cache.
138 if (s == NULL) {
139 return NULL;
140 }
141
142 ResourceMark rm;
143 CodeBuffer cb(s->entry_point(), amd64_code_length);
144 MacroAssembler* masm = new MacroAssembler(&cb);
145
146 #ifndef PRODUCT
147 if (CountCompiledCalls) {
148 __ incrementl(ExternalAddress((address) SharedRuntime::nof_megamorphic_calls_addr()));
149 }
150 #endif
151
152 // Entry arguments:
153 // rax: CompiledICHolder
154 // j_rarg0: Receiver
155
156 // Most registers are in use; we'll use rax, rbx, r10, r11
157 // (various calling sequences use r[cd]x, r[sd]i, r[89]; stay away from them)
158 const Register recv_klass_reg = r10;
159 const Register holder_klass_reg = rax; // declaring interface klass (DECC)
160 const Register resolved_klass_reg = rbx; // resolved interface klass (REFC)
161 const Register temp_reg = r11;
162
163 Label L_no_such_interface;
164
165 const Register icholder_reg = rax;
166 __ movptr(resolved_klass_reg, Address(icholder_reg, CompiledICHolder::holder_klass_offset()));
167 __ movptr(holder_klass_reg, Address(icholder_reg, CompiledICHolder::holder_metadata_offset()));
168
169 // get receiver klass (also an implicit null-check)
170 assert(VtableStub::receiver_location() == j_rarg0->as_VMReg(), "receiver expected in j_rarg0");
171 address npe_addr = __ pc();
172 __ load_klass(recv_klass_reg, j_rarg0);
173
174 // Receiver subtype check against REFC.
175 // Destroys recv_klass_reg value.
176 __ lookup_interface_method(// inputs: rec. class, interface
177 recv_klass_reg, resolved_klass_reg, noreg,
178 // outputs: scan temp. reg1, scan temp. reg2
179 recv_klass_reg, temp_reg,
180 L_no_such_interface,
181 /*return_method=*/false);
182
183 // Get selected method from declaring class and itable index
184 const Register method = rbx;
185 __ load_klass(recv_klass_reg, j_rarg0); // restore recv_klass_reg
186 __ lookup_interface_method(// inputs: rec. class, interface, itable index
187 recv_klass_reg, holder_klass_reg, itable_index,
188 // outputs: method, scan temp. reg
189 method, temp_reg,
190 L_no_such_interface);
191
192 // If we take a trap while this arg is on the stack we will not
193 // be able to walk the stack properly. This is not an issue except
194 // when there are mistakes in this assembly code that could generate
195 // a spurious fault. Ask me how I know...
196
197 // method (rbx): Method*
198 // j_rarg0: receiver
199
200 #ifdef ASSERT
201 if (DebugVtables) {
202 Label L2;
203 __ cmpptr(method, (int32_t)NULL_WORD);
204 __ jcc(Assembler::equal, L2);
205 __ cmpptr(Address(method, Method::from_compiled_offset()), (int32_t)NULL_WORD);
206 __ jcc(Assembler::notZero, L2);
207 __ stop("compiler entrypoint is null");
208 __ bind(L2);
209 }
210 #endif // ASSERT
211
212 // rbx: Method*
213 // j_rarg0: receiver
214 address ame_addr = __ pc();
215 __ jmp(Address(method, Method::from_compiled_offset()));
216
217 __ bind(L_no_such_interface);
218 __ jump(RuntimeAddress(StubRoutines::throw_IncompatibleClassChangeError_entry()));
219
220 __ flush();
221
222 if (PrintMiscellaneous && (WizardMode || Verbose)) {
223 tty->print_cr("itable #%d at "PTR_FORMAT"[%d] left over: %d",
224 itable_index, s->entry_point(),
225 (int)(s->code_end() - s->entry_point()),
226 (int)(s->code_end() - __ pc()));
227 }
228 guarantee(__ pc() <= s->code_end(), "overflowed buffer");
229 // shut the door on sizing bugs
230 int slop = 3; // 32-bit offset is this much larger than an 8-bit one
231 assert(itable_index > 10 || __ pc() + slop <= s->code_end(), "room for 32-bit offset");
232
233 s->set_exception_points(npe_addr, ame_addr);
234 return s;
235 }
236
237 int VtableStub::pd_code_size_limit(bool is_vtable_stub) {
238 if (is_vtable_stub) {
239 // Vtable stub size
240 return (DebugVtables ? 512 : 24) + (CountCompiledCalls ? 13 : 0) +
241 (UseCompressedClassPointers ? MacroAssembler::instr_size_for_decode_klass_not_null() : 0);
242 } else {
243 // Itable stub size
244 return (DebugVtables ? 512 : 140) + (CountCompiledCalls ? 13 : 0) +
245 (UseCompressedClassPointers ? 2 * MacroAssembler::instr_size_for_decode_klass_not_null() : 0);
246 }
247 // In order to tune these parameters, run the JVM with VM options
248 // +PrintMiscellaneous and +WizardMode to see information about
249 // actual itable stubs. Look for lines like this:
250 // itable #1 at 0x5551212[71] left over: 3
251 // Reduce the constants so that the "left over" number is >=3
252 // for the common cases.
253 // Do not aim at a left-over number of zero, because a
254 // large vtable or itable index (>= 32) will require a 32-bit
255 // immediate displacement instead of an 8-bit one.
256 //
257 // The JVM98 app. _202_jess has a megamorphic interface call.
258 // The itable code looks like this:
259 // Decoding VtableStub itbl[1]@12
260 // mov 0x8(%rsi),%r10
261 // mov 0x198(%r10),%r11d
262 // lea 0x218(%r10,%r11,8),%r11
263 // lea 0x8(%r10),%r10
264 // mov (%r11),%rbx
265 // cmp %rbx,%rax
266 // je success
267 // loop:
268 // test %rbx,%rbx
269 // je throw_icce
270 // add $0x10,%r11
271 // mov (%r11),%rbx
272 // cmp %rbx,%rax
273 // jne loop
274 // success:
275 // mov 0x8(%r11),%r11d
276 // mov (%r10,%r11,1),%rbx
277 // jmpq *0x60(%rbx)
278 // throw_icce:
279 // jmpq throw_ICCE_entry
280 }
281
282 int VtableStub::pd_code_alignment() {
283 return wordSize;
284 }